A. Rapports Reports Ponencias

Transcription

C O N F É R E N C E REGIONALE
O.I.E. - F.A.O.
S U R LES É P I Z O O T I E S EN ASIE
EN
EXTRÊME-ORIENT
ET EN
Canberra
OCEANIE
(Australie), 20-28 octobre 1969.
A. Rapports
Reports
Ponencias
Point 4 . — Brucellose. Epizootologie, Diagnostic, Prophylaxie.
Item 4 . — Brucellosis. Epizootiology, Diagnosis, Control.
Punto 4 . — Brucelosis. Epizootología, Diagnóstico, Profilaxis.
Bull.
Off. int. Epiz.,
1 9 7 0 , 73 ( 1 - 2 ) , 3 - 7 .
Epizootiology, Diagnosis and Control
of Brucellosis in India
by
C. Krishna RAO (*).
Cases of contagious abortion in cattle were first noticed
in India in some military dairy farms in 1 9 1 6 . However,
systematic work on this disease began only in 1 9 3 9 , when
POLDING ( 1 9 4 7 ) carried out an extensive serological survey
involving 5 , 9 9 6 cattle and 1 , 8 8 0 buffaloes. Since then, work
on the epizootiology of the disease has been confined mostly
to finding out the incidence of the disease in m a n , cattle,
sheep, goats and other domestic animals in different parts
of the country, by agglutination tests and determining
the species and types of Brucella affecting the different
host species. The results of serological surveys carried out
by different workers to determine the incidence of t h e
disease among cattle and buffaloes are given in Table I :
It will be observed from the Table that Brucellosis in
cattle and buffaloes is widespread in the country. However,
as the result of repeated testing and the removal of reactors
from organised farms, the incidence of t h e disease in m a n y
of the farms has been considerably reduced. Even in t h e
village herds, calfhood vaccination with Strain 1 9 vaccine
has reduced considerably the n u m b e r of abortions.
Brucellosis
in sheep,
goats and
pigs.
Serological evidence of infection has also been observed
in goats, sheep, pigs and even horses. In Table II, the
(*) A n i m a l H u s b a n d r y C o m m i s s i o n e r w i t h t h e G o v e r n m e n t o f I n d i a
(New Delhi).
—
4
—
TABLE I
Incidence
of
Brucellosis
in
cattle
and
NUMBER
REACTION
NUMBER
REACTION
TESTED
%
TESTED
%
India
(39
Bihar
Maharashtra
Gujarat
Madhya
Pradesh
Tamil Nadu
Mysore
Punjab
(a)
(b)
Orissa
Uttar Pradesh
POSITIVE
POSITIVE
STATE
All India
Assam
Bengal
aloes.
BUFFALOES
CATTLE
All
huff
5,994
herds)
4,778
160
674
7.6
(15
11.0
8.1
26.4
(13 d a i r y
23.5
18.1
6.8
1,880
herds)
8,787
5.8
9.8
65
herds)
24.6
619
14.7
3,784
9,716
13.47
41,207
3.5
(1,162 i u l l a g e s )
160
29.4
2.63
1,404
501
(Villages)
1,902
15-25
(Livestock Farms)
1,968
22.5
5.6
i n 1956-57
0.18 i n 1 9 6 1 - 6 2
3.7
81
1,947
631
2.59
(Livestock
Farms)
results of limited serological studies carried out in animals
other than cattle and buffaloes are given :
Individual milk samples from 15,568 goats in 1,231 villages
and from 14,937 sheep in 1,167 villages were subjected
to the milk ring test in one of the northern States of the
country. It was found that 6.54 percent of the goat and
5.06 percent of the sheep samples proved positive. Abortion
was recorded in 4,14 percent of the goats and 6.68 percent
of the sheep. W h e n the incidence of the disease was deter
mined flockwise, 29.06 percent of goat and 22.16 percent
of sheep flocks had positive reactors and 26.16 percent
of goat and 22.80 percent of sheep flocks had animals which
aborted.
— 5 —
TABLE
Incidence
of
Brucellosis
in
II
goats,
sheep
and
pigs.
SHEEP
GOATS
PIGS
STATE
NUMBER
POSITIVE
NUMBER
POSITIVE
NUMBER
POSITIVE
(District)
TESTED
REACTION
TESTED
REACTION
TESTED
REACTION
%
%
%
Haryana
(Hissar)
922
6.0
Madhya Pradesh
(Jabalpur)
959
3.9
Uttar Pradesh
(Bareilly and
Aligarh)
336
5.4
1,639
0.8
537
4.8
West Bengal
(Calcutta)
193
1.6
228
2.2
227
2.6
2,410
4.7
1,867
1.02
764
4.2
Total
Insolation
and typing
of
Brucellosis.
Various species of Brucella have been isolated from dif
ferent sources. POLDING (1947) isolated 48 cultures of
Brucella from different sources and found that 26 conformed
to the characteristics of Br. abortus, 20 from Tillage cattle
were intermediate between Br. abortus and Br.
melitensis,
and two were Br. melitensis. NILAKANTAN and PANDE (1948)
isolated Br. abortus (bio type 1) from goat's milk. Recently,
MATHUR (1968) studied the distribution of different types
of Brucella in m a n , cattle, sheep and goats in Haryana
and Punjab. He isolated Br. abortus type 1 and Brucella
melitensis type 3 from goats, Br. abortus type 1 and Br.
melitensis types 1 and 3 from sheep and all the three Br.
melitensis types from m a n . Recent work done at the Indian
Veterinary Research Institute on typing Brucella isolates
is dealt with in Table III :
Analysis of the data on Brucella infection in different
species of animals, including m a n shows that 96.5 percent
of Brucella infection in man in India has been found
—
6
TABLE
Distribution
of different
III
types
of Brucella
(SEN et al. 1 9 6 9 )
LOCALITY
STATE
—
in man
BRUCELLA
and
animals.
HOST
TYPES
Orissa
Cuttack
Bhubneslrwar
Bhubneshwar
B.
B.
B.
abortus
abortus
abortus
type 1
type 9
type 3
Cattle
Cattle
Cattle
Bihar
Uttar
Pradesh
Patria
B.
abortus
type 1
Cattle
Mathura
Izatnagar
Izatnagar
Izatnagar
Pantnagar
B.
B.
B.
B.
B.
abortus
type 1
abortus
type 3
melitensis
type
melitensis
type
abortus
type 1
B.
melitensis
type
3
Human
B.
B.
B.
B.
B.
B.
B.
B.
B.
B.
melitensis
abortus
abortus
abortus
abortus
abortus
melitensis
melitensis
melitensis
abortus
type
type 1
type 1
type 3
type 4
type 6
type
type
type
type 1
1
Human
Human
Cattle
Cattle
Cattle
Cattle
Cattle
Goat
Human
Human
Ranipet
B.
melitensis
type
1
Cattle
Kurnool
Aurangabad
Poona
B.
B.
B.
melitensis
type
melitensis
type
abortus
type 1
1
Sheep
Sheep
Goat
Delhi
Tamil
Nadu
Andhra
Pradesh
Maharashtra
West Bengal
Vellore
Vellore
Ranipet
Ranipet
Ranipet
Ranipet
Ranipet
Ranipet
Ranipet
Ranipet
1
1
2
1
1
1
Cattle
Cattle
Sheep
Goat
Cattle
to be due to Br. melitensis, white in cattle and buffaloes,
9 7 . 8 2 percent is due to Brucella abortus and in sheep and
goats, 8 2 . 1 1 percent is due to Brucella melitensis.
MATHUR
( 1 9 6 8 ) reported that out of 53 positive cultures isolated
by h i m from h u m a n beings 2 2 were from shepherds and
7 from persons who kept goats. In 7 instances, two members
of the same family contracted the disease.
Diagnosis.
The standard
standardised Br.
tube agglutination test (S.T.T.), using
abortus Strain 9 9 antigen, is commonly
—7—
used for determining incidences of Brucellosis. The plate
agglutination test and milk ring test are also used for
screening herds. It was observed that in herds where a
policy of regular testing and segregation of reactors was
strictly practised, the heat inactivation test (H.I.T.) proved
to be a useful adjunct to S.T.T. in the elimination of
low-titre and non-specific reactors.
Agglutination tests in sheep and goats, which species
usually suffer from Br. melitensis type of infection does
not give reliable results in individual animals. However,
it has been observed that Br. melitensis antigen for this
purpose would be more useful as this method would detect
a greater n u m b e r of reactors.
Control.
The test-and-segregation method is generally adopted to
control the disease on farms where the incidence is less
than 5 percent. In the second category of farms where
the incidence is more than 5 percent, in addition to the
test-and-segregation method a n d / o r the disposal of infected
animals, calfhood vaccination of heifers with Br. abortus
strain 19 is practised. Vaccination of adult cows, combined
with other methods, has been used on farms with a h i g h
rate of abortion and a rate of incidence shown b y tests
to be more than 20 percent. Adoption of these methods
has resulted in a considerable reduction in the incidence
of the disease in m a n y of the organised farms in the country.
In one of the States in the country (Tamil Nadu), control
of Brucellosis in village herds was undertaken. An extensive
survey was first undertaken involving 1,162 villages and
41,207 cattle, when an overall infection rate of 3.5 percent
was found. There were some herds where there were
20-30 percent reactors a m o n g the animals tested. As m a n y
as 46,127 animals in 414 villages have been vaccinated
with strain 19 during the last seven or eight years.
Trials are also being carried out to find out the efficacy
of « Duphavac », a killed adjuvant vaccine claimed to be
non-agglutinogenic, in comparison with Strain 19 and killed
adjuvant Br. melitensis H 38 vaccines. Results so far obtained
indicate that the « Duphavac » is not completely nonagglutinogenic.
Bull. Off. int. Epiz., 1970, 73 (1-2),
9-16.
Brucellosis in Thailand
by
Siri S U B H A R N G K A S E N
(*).
The first recognition of Brucellosis was reported in
imported swine and cattle in 1951. Not much research
work had been undertaken up to that time as the country
was confronted with a more economically important disease,
viz. Rinderpest. Bovine Brucellosis is most frequently caused
by Br. abortus. Br. suis and Br. melitensis have been reported
occasionally to be the cause of Brucellosis in bovine animals,
which, however, are relatively resistant to these two species,
the infections being infrequently associated with clinical
signs and usually transient.
A survey of Brucellosis was started in 1959 and the
incidence of the disease is shown in the attached Tables.
Diagnosis.
Brucellosis is suspected in a herd when abortions are
frequent and appear to be spreading. There are no specific
symptoms or physical signs whereby the presence or absence
of Brucellosis can be established. It is generally impossible
to differentiate abortions due to Brucellosis from those
caused by other infections, except that they do not take
place during the first few months of pregnancy. A positive
blood test or the recovery of the organism from the animal
will establish a definite diagnosis.
(*) Deputy Director General, Department
Bangkok (Thailand).
of Livestock
Development,
— 10 —
The isolation of Brucella organisms is the most desirable
but often the most impractical method of diagnosis. Isolation
attempts have been made occasionally in guineapigs with
fairly satisfactory results. Brucellae isolated locally were
confirmed by courtesy of Walter Reed Army Institute of
Research (U.S.A.).
The tube and plate sero-agglutination tests are the most
practical methods of diagnosis.
1. Tube or slow agglutination test. The blood serum
(unheated) is mixed with a specially selected strain of
Br. abortus (provided through the courtesy of Animal Health
Div. US Dept. of Agrie.) in a series of several tubes beginning
with a.dilution of 1 : 50 and doubling the dilution in each
successive tube, 1 : 100, 1 : 200. The interpretations are
as follows :
1. No agglutination at 1 : 50
= negative
2. Reactions at dilution 1 : 50 and
no reactions in higher dilutions . .
= suspicious
3. Agglutination complete at dilution
1 : 100 and higher
= positive
2. Plate or rapid agglutination test. W h o l e blood
(unheated) is used. With a 0.2 ml. pipette graduated to
0.01 ml., the following amounts of the undiluted serum
under test are pipetted on the glass plate (the plate is pre
viously marked off in squares, for convenience), each amount
being placed into a different square : 0.08 c . c , 0.04 c . c ,
0.02 c . c , 0.01 c.c. and 0.005 c.c. Immediately afterwards,
one drop of concentrated antigen is added to each lot of
serum and thoroughly mixed with it. Such of the dilutions
will give results' comparable to those of 1 : 25, 1 : 50,
1 : 100, 1 : 200, 1 : 400 respectively in the standard tube
test. The reactions can be read immediately, but it is
advisable not to draw conclusions until 8 minutes have
elapsed.
The readings are interpreted as follows :
Swine.
=
negative
— 11 —
2. Agglutination at 1 : 25
suspacious
3. Agglutination at 1 : 50 and higher
positive
Bovine.
negative
2. Agglutination at 1 : 25 - 1 : 50 . .
suspicious
3. Agglutination at 1 :100 and higher
positive
Control.
Brucellosis has not yet been scheduled under the Infec
tious Animal Disease Act B.E. 2499 (1956). It is listed,
however, under the Ministerial law, and strict control
measures, such as slaughter of affected animals with com
pensation, as well as condemnation of the carcases, cannot
be enforced. Voluntary control measures, nowadays, are
used.
Calfhood vaccination at the age of 4-6 months in the
government breeding stations has been put into practice.
Artificial insemination is provided by the Government to
livestock owners free-of-charge for both bull semen and
insemination on condition that the cow is brucellosis-free
as shown by tests. Through this policy, we certainly hope
that the voluntary control measures will be strengthened
to a great extent.
«
T—1
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12 —
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OATTLE
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PROVINCES
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POSITIVE I PERCENT
BUFFALOES
ANIMALS
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1
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0.56
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^ POSITIVE j PERCENT
CATTLE
THE INCIDENCE OF BRUCELLOSIS IN THE EAST REGION
POSITIVE
PIGS
1.54
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— 15 —
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Bull.
Off.
int.
Epiz.,
1970, 73 ( 1 - 2 ) ,
17-27.
Present Situation of Brucellosis
in J a p a n
by
Kenzo NOBUTO (*) and Koji SUTO (**).
In 1913, Brucellosis became the object of public attention
when the Brucella organism was isolated from diseased
cattle. Since then, a campaign has been launched to control
the disease and killed and live vaccines were used in 19231950 and 1928-1946 respectively. From 1930, antigen has
been utilized to diagnose this disease. In general, the size
of dairy farming of Japan was then so small that the disease
very rarely spread over a wide region.
From 1950, Japan's animal industry began to emerge
as a very important and growing sector of her agriculture
and in order to meet the increasing demand for milk and
milk products, Jersey cattle have been imported regularly
from the United States, Australia and New Zealand from 1953.
Because of this impetus, the incidence of Brucellosis and
the n u m b e r of isolations of Brucella organism have increased
since 1956.
To meet this, the Domestic Animal Infectious Disease
Control Law was amended in 1956. There is now compulsory
inspection of dairy cattle for Brucellosis, to be carried out
throughout the country at least once a year and to ensure
(*) A n i m a l H e a l t h D i v i s i o n , B u r e a u of A n i m a l
of A g r i c u l t u r e a n d F o r e s t r y , T o k y o ( J a p a n ) .
(**) N a t i o n a l I n s t i t u t e of
and Forestry, Tokyo (Japan).
Animal
Health,
Industry,
Ministry
of
Ministry
Agriculture
— 18 —
eradication by early discovery, the slaughter of infected
cattle with the payment of compensation, is enforced.
Up to 1964, from 200 to TOO cattle have been exposed each
year.
Because of the decrease in the n u m b e r of cases since 1960
in which Brucella organisms were isolated from agglutinationreactors, a special investigation scheme has been imple
mented from 1964 in 13 prefectures to ensure the effective
criteria of Brucellosis diagnosis. Based upon the findings
of this investigation, in order to increase the accuracy of the
agglutination test and the isolation of Brucellae, the standard
method for diagnosis was amended in 1966.
Because of this amendment concerning diagnosis and
because of the progress in eradication throughout the country,
the morbidity of Brucellosis declined from 0.07 percent in
1964 to 0.004 percent in 1968. Since the incidence is now
confined to a very limited area, it can be reasonably assumed
that the disease in Japan is nearly cleaned u p . The incidence
of Brucellosis during 1961-1967 is shown in Table I.
TABLE I
The
yearly
incidence
of
Brucellosis.
No.
No.
YEAR
OF
36
37
38
39
40
41
42
43
DAIRY
No.
CATTLE
884,940
1,001,690
1,145,370
1,238,300
1,288,950
1,309,970
1,376,652
1,489,000
OF
INSPECTED
820,319
856,382
986,028
1,019,290
1,030,966
1,008,057
1,094,652
1,235,222
No.
OF
DISEASED
MORBIDITY
OF PREF-
CATTLE
(%)
30
32
35
40
37
22
19
19
245
261
517
703
596
134
64
51
0.03
0.03
0.05
0.07
0.06
0.01
0.006
0.004
Diagnosis.
The method of examination for bovine Brucellosis in
the past was based on the detection of the agglutinin,
using the plate agglutination test. The diagnosis, however,
was finally decided by the application of the tube agglu-
— 19 —
tination test. As the examination work progressed and the
number of cows examined increased, the discrepancy
between the results of the plate test and those of the tube
test cropped up. The most important problem was that
Brucella could not be isolated from many cattle which
were definitely positive to agglutination tests, when they
were examined after slaughtering.
F I G . 1 . —• P o t e n c y D i s t r i b u t i o n
of
7 , 1 9 8 Bovine
Sera.
— 20 —
During about the past ten years, we have collected many
samples of serum from cattle slaughtered because of their
positive reaction to the Brucella agglutination tests. We
examined them serologically and tried to evaluate the results
with the bacteriological findings. Furthermore, a special
survey over a period of three years was planned to obtain
data for improvement of the examination technique.
Part of the results of the 1965 survey is shown in Fig. 1.
From these conclusions, it is apparently impossible to
consider that the results of the plate agglutination test
will correspond to those of the tube test. According to the
tube agglutination test results, a considerable n u m b e r of
cows should be diagnosed as affected with Brucellosis when
83 IU is used as the minimal positive limit for agglutinin
content. A similar tendency was observed in the next year's
survey.
Most of the agglutinin-positive sera were negative with
the complement fixation (C.F.) test, and the cows in question
were observed during the following several months. A definite
increase of the agglutinin titre was not observed in their
sera and there was a decrease in the sera of most of them.
Some of the cows were slaughtered, b u t Brucella could
not be isolated from them.
Cows which were known to have come into contact with
contaminated ones or cows positive to the C . F . test were
slaughtered. From most of them Brucellae were isolated
and they were all identified as Br. abortus type I, whereas
until that time all Brucella isolated in Japan had been
regarded as belonging to type II.
From these results, it.was concluded that in Japan, it is
not adequate to diagnose bovine Brucellosis simply by the
agglutination results. Before the adaptation of the inter
national unitage system of the agglutinin as the diagnostic
standard, the American style agglutination method was used
and at that time, KAWASHIMA et al. suggested that the C . F .
test was a beneficial supplemental test, which had been
applied in our Institute.
Washed Br. abortus St. 544 cells are extracted with 2 percent
phenol-saline in an incubator at 22° C . for two weeks.
— 21 —
The suspension is centrifuged and the supernatant is used
as the antigen.
Afterwards, the extract from St. 99 or St. 125 was shown
to have the same potency as St. 544. We compared the
results obtained by the different antigens in this survey.
The C.F. (S) curve in Fig. 1 shows the results obtained
by our soluble antigen, and C.F. (G) shows those with
the diluted agglutination antigen. The curves are similar
to each other but are different from that of the agglutination.
More sera are positive with the C.F. test, using the cellular
antigen.
The results of both C.F. tests, arranged according to
the origins of the sera, are summarized in Table II. In the
noninfected herds, the rate of C.F. (S) reactors is less than
in the infected herds, and all but one are suspicious reactors,
whereas those in the infected herds are mostly high titre
reactors. The results of the C.F. (G) test in the infected
herds are not very different from those of the C.F. (S) test,
but in the noninfected herds, the positive reactors increase
in the C.F. (C) test.
T A B L E II
CF Tests,
using
different
antigens.
REACTION
ORIGIN
OF
SERUM
Neg.
X
5
X 10
or
Non-infected
Infected
Herd
Herd
X 20
more
Soluble
Cellular
6,726
6,687
1
14
0
32
Soluble
Cellular
454
452
2
3
1
8
2
8
6
Some of the sera of the slaughtered cows which contained
50 I.U. or 100 I . U . / m l . of the agglutinin and were negative
with the C.F. (S) test, gave positive reactions with the
C.F. (C) test.
0
— 22 —
On the other hand, TANAKA examined the nature of the
soluble antigen and demonstrated that it resembled chemi
cally and biologically Boivin's antigen of the bacteria of
Enterobacteriaceae. The antibody against the soluble antigen
appeared several days later than the agglutinin in the sera
of the inoculated cows.
The C.F. antibody in the sera of the cows which had
been infected for a long time with the virulent strain could
be absorbed completely by the cells, b u t the agglutinin
was absorbed incompletely by the soluble antigen. From
these results, it can be concluded that the soluble antigen
may be a part of the surface antigens of Brucella.
The cows which had been diagnosed as being infected
with Brucellosis were examined bacteriologically and sero
logically. The relation between the agglutination titres and
the Brucella positiveness is shown as a sigmoid curve, and,
on the contrary, that of C.F. (S) titres is an exponential
one (Fig. 2).
From these results, it might be thought that the natures
of the antibodies which are detected with both tests respec
tively are somewhat different from each other. Brucellae
are isolated from one-third of the cows which contain
150 I.U. of the agglutinin in the sera. On the other h a n d ,
from about a half of the cows which are positive at one-fifth
dilution in the C.F. (S) test, the organisms are isolated,
and this titre is generally accepted as suspicious.
The antigen for the plate agglutination test is made from
Br. abortus St. 125. The concentration is one hundredfold
the McFarland standard No. 1. The cells are suspended in
2 percent saline. It has been demonstrated that when 0.04 m l .
of the antigen is mixed with 0.02 ml. of a s e r u m which
contains more than about 30 I.U. per ml. of the agglutinin,
some agglutination is observed. If the agglutination is
observed when 0.04 ml. of a serum is mixed, the serum
contains more than 15. I.U. and less than 30 I.U. per m l .
To distribute such a small amount of liquid, a dropping
pipette, a drop from which is 0.02 ml. has been adopted.
About 500 of the sera collected were examined, using
the modified plate agglutination method. The results are
shown in Fig. 3. A dot represents one serum sample.
— 23 —
F I G . 2. —
A n t i b o d y T i t r e a n d Brucella
Positiveness.
— 24 —
The dots in the first and third quadrants represent the sera
in which both tests give similar results. The rate of coin
cidence is about 76 percent. There are only about 2 percent
of sera which contain less than 30 I.U. of the agglutinin
per ml. and give positive results with the plate test.
The sera which give negative results with the plate test,
irrespective of the demonstration of more than 30 I.U. of
the agglutinin in the tube test, amount to about 21 percent.
However, about 85 percent of the escaped ones contain
less than 50 I.U. of the agglutinin per m l . and the sera
of more than 100 I.U. do not escape. Subsequently, it was
concluded that the plate test is to be used as a screening
method. But as it takes much time to handle a n u m b e r
of the sera by this method, some m o r e time-saving method
is to be designed in the future.
From the above results, we designed and proposed the
following diagnostic system, and this has been accepted
by the Ministry and was made public from the beginning
of 1968. The system is that the sera of all dairy cows are
examined by the plate test. All sera which have been found
to contain more than 30 I.U. of the agglutinin per m l .
are further examined by the tube test. The concentration
of the tube antigen is increased to show 50 percent agglu
tination in 20-fold diluted serum, which contains 50 I.U.
of the agglutinin per m l .
The sera containing more than 50 I.U. are examined
by the C.F. test, using the soluble antigen. The cows raised
in the same herd with the positively diagnosed one are
all regarded as heing suspicious and their sera are examined
by the C.F. test, irrespective of the agglutinin content.
The diagnostic standard of the results is shown in Table III.
Sera which inhibit more than 50 percent of the haemolysis
in five-fold dilution in the C.F. test are diagnosed as Brucel
losis-positive, irrespective of the agglutinin content. Cows
negative by the C.F. test and containing less than 100 I.U.
of the agglutinin in the sera are diagnosed as negative.
Cows containing 100 I.U. of the agglutinin in the sera
are diagnosed as suspicious and are to be observed for
several months. Cows containing more than 200 I.U. of
— 25 —
TABLE
Serodiagnostic
Standard
CF
AGGLUTININ
X
III
of Bovine
Brucellosis.
TEST
5 Dilution
DIAGNOSIS
200 L U .
or m o r e
+
Positive
100 L U .
+
Positive
Suspicious
50 I.U.
+
Positive
Negative
* Less t h a n
50 I.U.
Positive
Negative
+
—
* From the cows in the same herd with the positive
one.
the agglutinin in the sera are diagnosed as Brucellosispositive, without reserve. However, it is expected that the
accumulation - of the data on such cows may be a cause
for changing their designation.
Three years ago, some cows in several herds in a village
where about 20,000 cows were raised, were found to be
infected with Brucella. All the cows in the village were
examined according to the above system and the reactors
were removed. After three years consecutive examination,
there were no cows which could be diagnosed as apparently
infected. In this case, the diagnosis standard was increased
and the cows which were in the same herds with the sus
picious ones were all examined, but no positive animals
were detected.
Method of
Control.
Since the incidence of Brucellosis is very low in Japan,
the test-and-slaughter method is adopted. Periodical inspec
tion is regularly enforced under the Domestic Animal Infeclious Diseases Control Law and its Enforcement Regulations
— 26 —
and diseased cattle are diagnosed and slaughtered. The live
vaccine widely used abroad has not been used in Japan
since 1946.
Regular inspection is carried out at least once a year
under the order issued by the prefectural governor to farmers
rearing cattle, and the cattle subjected to inspection are
dairy cattle and breeding bulls as well as cattle raised in
the same establishment with them.
Diseased cattle delected at such a regular inspection are
slaughtered. The owner of the slaughtered cattle receives
compensation equal to four-fifths of the value of the animals.
However, maximum compensation is set and when a carcase
has some value, the amount is deducted from the com
pensation.
In 1968, a nationwide investigation was carried out on
the scope and extent of Brucellosis in cattle not subjected
to duly enforced regular inspection (mainly beef cattle).
The findings have shown that the reactor distribution of
Brucellosis in these cattle is lower in comparison to that,
in cattle subjected to the present inspection (mainly dairy
cattle). However, in order completely to eradicate the disease
from Japan, the enforcement of cattle inspection is strongly
advocated.
*
SUMMARY
In Japan, the incidence of Brucellosis has increased in
conjunction with the importation of Jersey cattle from
abroad in 1953 ; the incidence of cases from which the
Brucella organism is isolated has also gone u p . Since then,
the enforcement of slrict control measures in the districts
where Jersey cattle were introduced and in the infected
areas, has brought about a great decrease of diseased cattle
and the incidence is now confined to limited areas. Japan
is now strengthening the control of the disease in infected
areas and the whole of the structure of the control, with
the eradication of this nationwide Brucellosis as the ultimate
objective.
— 27 —
However, Japan has been importing domestic animals
from abroad frequently in recent years ; thus, the risk
of the introduction of the disease from overseas is ever
increasing. In order to exclude such a risk, our animal
quarantine service is being intensified, but it is very dif
ficult completely to keep out this chronic disease. Moreover,
complications have arisen concerning the inspection conduc
ted at the port of entry, when live vaccine was used. In
conjunction with the marked progress toward achieving the
ultimate eradication of Brucellosis, the most vital problem
confronting Japan in the control of Brucellosis is to stop
completely the introduction of this disease from abroad.
Bull.
Off.
int.
Epiz.,
1970, 73 ( 1 - 2 ) ,
29-32.
Control of Bovine Brucelosis
in New-Zealand
by
R. M. DAVIDSON (*).
INTRODUCTION
It is fortunate that only a very few of the animal diseases
dealt with in the International Zoo-Sanitary Code of the
Office International des Epizooties are to be found in New
Zealand. None of the major epizootic diseases exist, but
bovine Tuberculosis and Brucellosis are present. All dairy
herds are now subjected to regular tuberculin testing and
eradication of bovine Tuberculosis from the national dairy
herds should be complete by the early 1970's. Beef cattle
are now being brought under test, and it is expected
that all herds will be tested by 1975.
BRUCELLOSIS IN NEW ZEALAND
Of the three classical species of Brucella affecting livestock,
only Brucella abortus is to be found in New Zealand.
Vaccination with S 19 vaccine has been a common practice
in dairy herds for many years. Prior to 1966, it was estimated
that about 80 percent of all female dairy-type calves, and
many beef heifers, were vaccinated on a voluntary basis. As
a first step in the official control of bovine Brucellosis, vacci
nation of all female calves between the ages of 4 months and
8 months (dairy-type animals) and 4 and 10 months (beet
(*) V e t e r i n a r y A d v i s o r y Officer ( I n f e c t i o u s D i s e a s e s ) , A n i m a l H e a l t h
D i v i s i o n , D e p a r t m e n t of A g r i c u l t u r e , P.O. B o x 2 2 9 8 , W e l l i n g t o n . N.Z.
— 30 —
breeds) was made compulsory at owners' expense in 1966.
The higher m a x i m u m age for beef calves was adopted as
this enabled vaccination to be carried out at the time of
weaning. This is an important practical consideration in large;
beef herds.
However, with the publication of the International Code
in 1968, it has become necessary for New Zealand to move
faster towards a policy of eradication. To reduce the problem
of S 19 vaccination affecting diagnostic tests for Brucellosis,
legislation will shortly be introduced altering the m a x i m u m
age for vaccination to six months, and allowing a reduction
in m i n i m u m age to three months. Though the period over
which the annual total of 650,000 dairy calves can be vacci
nated will be reduced, no problem is anticipated in com
pleting the work. W i t h the reduction in the m i n i m u m age
to three m o n t h s , beef calves can be vaccinated at the time
of the marketing muster when most calves are about that
age. Late calves, less than three months old at the marketing
muster, can be vaccinated at weaning and still be under six
months of age.
A test and slaughter scheme will commence this year
(1969). Initially, it will start as a voluntary scheme, and all
owners of cattle in a prescribed area may apply to have
their herds tested. The first area opened for testing is mainly
a dairy-farming area, though there are a few beef herds. All
cows, and also bulls six months and older, will be eligible
for testing.
Examination of bovine sera by the serum agglutination
test (S.A.T.) and complement fixation test (C.F.T.) for the
presence of Brucella abortus antibodies requires highly train
ed technicians, and extensive laboratory facilities are neces
sary when large numbers of sera have to be processed in the
course of a national control scheme. A simple test which
can be carried out in the field with a m i n i m u m of equipment,
and which is easy to perform and read, will reduce the work
load on laboratories which would otherwise be necessary.
Such a test, the Brucellosis Card Test (B.C.T.) (*) has been
developed in the U.S.A.
(*) B r e w e r D i a g n o s t i c Kit, B r u c e l l o s i s C a r d T e s t . M a n u f a c t u r e d
H y n s o n , W e s t c o t t a n d D u n n i n g Inc., B a l t i m o r e , M.D., 2 1 . 2 0 1 .
by
— 31 —
This technique has been evaluated in 5,504 animals in
73 dairy herds, in various parts of New Zealand, which were
positive to the r i n g test on bulk milk. In 93 percent of ani
mals there was agreement between the B.C.T. and standard
serological tests. Because of this good correlation, it has been
decided to use the B.C.T. as a screening test in the New Zea
land scheme.
Blood will be collected by technicians mostly by puncture
of the middle coccygeal artery or vein, using evacuated glass
tubes and fine-gauge needles. This method is relatively fast
and simple under New Zealand conditions of cattle husbandry
compared with conventional jugular bleeding. The B.C.T.
on sera will be undertaken in the field by these technicians.
In this test, 0.03 ml of serum is mixed with two drops
(0.03 ml) of stained antigen in a tear-shaped cup impressed
on a card, and rocked for four minutes. To standardise the
amount of mixing, automatic oscillators will be employed.
The test is read on a positive or negative basis only, positive
reactions being evidenced by agglutination of the stained
antigen.
Sera which are positive to this test will be forwarded to a
central laboratory for confirmation by the S.A.T. and C.F.T.
according to the following formula :
Positive
. . (a) S.A.T. of more than 80 I.U.
or (b) S.A.T. of 30 I.U. or more but not more
but not more than 80 I.U.
with the C.F.T. being positive.
Negative . . (a) S.A.T. of less than 30 I.U.
or (b) S.A.T. of 30 I.U. or more but not more
than 80 I.U.
with the C.F.T. being negative.
The S.A.T. to be used is the Weybridge test, and the
C.F.T. will be carried out as described by ALTON and JONES
(1967).
Confirmed reactors will be permanently identified by a
special earpunch and can only be disposed of by slaughter.
Owners will receive carcase value plus an amount of com
pensation ($ 16) for every reactor slaughtered. Herds will be
kept under test until there have been two tests, at an interval
— 32 —
of at least six months, at which no reactors have been dis
closed. W h e n dairy herds meet this criterion they will be
kept under surveillance by twice yearly tests on bulk milk
specimens (using the Milk Ring Test), or in the case of beef
herds, by serological testing of bloods collected at slaughter
of culled breeding animals. W h e n there is evidence of a
herd having become re-infected, all eligible cattle will be
tested again.
Milk Ring Tests will be carried out by Department of Agri
culture technicians in the dairy factories at which milk is
processed. For slaughter cattle testing, a system which per
mits ready identification of animals with their herds of origin
is being developed.
In future years, progressively larger areas of the country
will be opened u p for voluntary testing, and eventually test
ing will become compulsory. W h e n clear areas are establish
ed (i.e., all eligible cattle under surveillance and reactors
being a proportion of 0.2 percent or less of the total) compul
sory vaccination within that area will be reviewed, and will
cease if it is judged that reinfection is unlikely. At this stage
also, regulations will be enforced to control the movement
of cattle into such areas to ensure that diseased animals are
not introduced.
*
**
REFERENCE
ALTON ( G . C.) & JONES (L. M.). — Laboratory
Techniques
in Brucellosis. Monograph Ser. W . H . O . , No. 5 5 , 1967.
Point 5 . — Leptospiroses. Epizootologie, Diagnostic, Prophy
laxie.
Item 5 . — Leptospiroses. Epizootiology, Diagnosis, Control.
Punto 5. — Leptospirosis. Epizootologia, Diagnóstico, Pro
filaxis.
Bull.
Off.
int.
Epiz.,
1 9 7 0 , 73 ( 1 - 2 ) , 3 5 - 3 8 .
Epizootiology of Leptospirosis
in India
by
C. Krishna RAO (*).
CHOWDRY ( 1 9 0 3 ) first recorded the occurrence of Weil's
disease in h u m a n beings in Andamans. Five hundred and
eighty eith cases were recorded in a period of ten years
from 1 8 9 2 , of which 7 8 ( 1 3 . 2 percent) ended fatally. It was
BAKER ( 1 9 2 4 ) , however, who presented microscopic evidence
of the presence of Leptospires in the morbid materials of
affected cases. Further confirmation of the leptospiral etiology
of the disease was reported by BROWN ( 1 9 2 8 ) on the basis of
serological tests and by KNOWLES ( 1 9 2 8 ) who demonstrated
leptospires in tissue sections. TAYLOR and GOYLE ( 1 9 3 1 ) made
an extensive study of leptospiral jaundice in Andamans and
isolated Leptospira andaman and L. grippotyphosa
from a
series of cases.
On the Indian mainland, a severe and widespread epidemic
of jaundice in Bombay was described in 1 9 5 6 . Of the 1 0 cases
recorded, 9 showed acute symptoms and ended in death. In
an outbreak of infectious jaundice investigated by PARMANAND
( 1 9 2 2 ) , spirochaetes were detected in the centrifuged urine of
2 out of 7 cases. Since 1 9 3 1 , there have been a n u m b e r of
reports of h u m a n cases of leptospiral disease and leptospires
were isolated also from rats in the affected areas.
Among the domestic livestock, except a solitary report in
1 9 3 2 of an outbreak of highly fatal leptospiral jaundice
(*) A n i m a l H u s b a n d r y C o m m i s s i o n e r w i t h t h e G o v e r n m e n t of
India.
— 36 —
affecting hounds in Madras State, Leptospirosis as an animal
health problem had not been investigated until recently.
During the past decade, there have been reports on serologi
cal evidence of the occurrence of leptospiral infection in
animals and suspected leptospiral infection as the probable
cause of certain diseases of unknown etiology. In fact, the
intensification of investigational work on the prevalence of
Leptospirosis in animals is largely due to the occurrence of
certain disease conditions suggestive of having a leptospiral
etiology. For instance, many cases of abortion are known to
occur in herds not affected with Brucellosis. In some parts
of the country, cattle and buffaloes suffer from haemoglobinuria with a febrile course, and repeated attempts have failed
to demonstrate piroplasms in the peripheral blood of the
cases examined. During the past few years, considerable evi
dence has accumulated to show that leptospiral infection may
be associated with some cases of abortion among the farmstock.
A systematic investigation was initiated recently at the
Indian Veterinary Research Institute, to determine the preva
lence and distribution of Leptospirosis in relation to live
stock health and productivity in India. Random serum sam
ples received and those collected from different parts of the
country were examined for leptospiral antibodies. Of the
373 serum samples examined, 222 were from cattle, 55 from
buffaloes, 26 from sheep, 20 from goats and 50 from equine
animals. A large majority of these were from animals with a
history of abortion or from herds where abortions had occur
red in the recent past. For example, buffalo sera from P u n j a b
were from cases of haemoglobinuria of u n k n o w n etiology.
The samples of sera were examined by the microscopic agglu
tination test, using live antigens of a n u m b e r of serotypes
which included L. autamnalis,
L. australis, L. ballum,
L.
canicola, L. grippotyphosa,
L. icterohaemorrhagiae,
L. Javanica, L. mini, L. pomona, L. saxkoebing, L. seiro, L. tarassovi, and L. wolffi (Of the hebdomadis sero-group different
serotypes were used on different occasions).
Of the 373 serum samples, 119 were found to have signi
ficant agglutinin titres (1 : 100 and above) for one or more
leptospiral serotypes. Apart from cross-reactions with sero
types of the same group (hebdomadis),
32 sera reacted with
— 37 —
more than one serotypes belonging to different serogroups
and the remainder Teacted specifically with single antigens
or serotypes of the same group. Of the positive sera, 109 were
positive for antibodies for one or more serotypes of hebdomadis group, 28 for L. pomona,
10 for L.
autumnalis,
5 for L. icterohaemorrhagiae,
4 each for L.
grippotyphosa
and L. tarassovi, 2 for L. canicola and one for L. australis
(ballico). The Slate and animal host distribution of serum
samples examined and found positive is detailed in Table I.
TABLE
Animal
host
examined
and
for
STATE
the State
leptospirae
CATTLE
Andhra Pradesh
Himachal Pradesh
Kerala
Maharashtra
Mysore
Punj ab
Uttar Pradesh
3(2)
*
54(3)
38
(24)
57
(31)
44
(1)
26
(12)
I
distribution
antibodies
BUFFA
LOES
of serum
(KHBRA,
SHEEP
GOATS
EQUINE
ANIMALS
5(5)
2<—)
6(4)
6(—)
20
(15)
14
{—)
6(3)
15(9)
27
(5)
* Figures in parenthesis represent the n u m b e r
Human
samples
1968).
50(5)
of p o s i t i v e
reactors.
sera.
Nine h u m a n serum samples — two paired sera from one
patient from Madras State and 7 from Rajasthan — were
examined for leptospiral antibodies. Two sera from Madras
showed rising titres of antibodies of two serotypes, namely,
L. icterohaemorrhagiae
and L. grippotyphosa,
the convales
cent, serum gave titres over 1 : 1,000. The seven samples
from Rajasthan were negative for evidence of recent leptos
piral infection.
Leptospira
isolation.
Attempts made so far for the isolation of leptospirae from
morbid materials from suspected cases have not yielded posi
tive results. These failures are attributable to difficult con
ditions of field invcsligation of animal disease in rural areas,
— 38 —
lack of necessary laboratory facilities, and probably unsatis
factory isolation techniques. In addition to the conventional
culture media such as Korthof's, Stuart's and Fletcher's, the
recently developed bovine albumin-polysorbate 80 medium,
which has given encouraging results abroad, is being used
in the isolation studies.
Wild rodents are known to play an important rôle in the
epidemiology of Leptospirosis. The field studies were extend
ed to determine the rôle of wild rodents found on farm
premises. For instance, 165 rats, 9 mice and one shrew trap
ped in Mukteswar premises were examined by kidney cul
ture in various culture media for leptospiral infection. Of
these, only one rat yielded a strain of leptospira which, on
the basis of preliminary antigenic analysis, appears to resem
ble L. pyrogenes.
Serological evidence indicates the prevalence of leptospirae among domesticated animals in different parts of the
country. More intensive studies will show the extent to which
such infection is responsible for losses in animal production
Bull.
Off.
int.
Epiz.,
1970, 73 ( 1 - 2 ) ,
39-42.
Leptospirosis in Thailand
by
Siri SUBHARNGKASEN (*).
Leptospirosis was first reported in Thailand. 1 0 years ago
A preliminary survey of the disease in cattle, buffaloes
and swine in the North and North-East regions was carried
out, using two serotype antigens of a commercial firm
(L. canicola, L. icterohaemorrhagiae).
The results showed
the following rates of infection :
(1959).
Cathie
Pigs
EXAMINED
POSITIVE
PERCENTAGE
2,606
2,136
897
762
583
6!)
29.20 °f27.29 %
7.69 %
Because of the high incidence of Leptospirosis, an attempt
was made to isolate the organism in domestic livestock.
Kidney sampling study was begun at Bangkok slaughterhouse
where cattle, buffaloes and swine are brought from various
provinces of the country. Groups of animals, randomly
selected for study, were made before slaughter, with the
purpose of identification of areas from which the animals
originated. Cultural methods of Leptospira isolation (sub
mitted to F.A.O. Conference on Pig Production and Diseases
in the Far-East, Bangkok, 1 9 - 2 4 February, 1 9 6 8 , by C. WONGSONGSARN et al.) are as follows :
(*) D e p u t y D i r e c t o r G e n e r a l , D e p a r t m e n t
Bangkok (Thailand).
of L i v e s t o c k
Development,
— 40 —
After slaughter of the animals, one kidney was removed
aseptically and placed in a sterile specimen box. In an
aseptic manner, the peri-renal fat is removed and discarded.
The kidney is halved mid-sagitally and placed with both
cortical surfaces up. The kidney capsule is then removed.
The superficial cortical surfaces are cut away, leaving
natural-coloured cortical tissue underneath. Kidney tissue
is then collected and put in 1.5 c.c. of liquid Stuart's
media without rabbit serum. One drop from this suspension
is cultured in each of 3 tubes of semi-liquid Fletcher's
medium containing 8, 12 and 16 percent of rabbit serum.
The cultures were dark-field examined at 15-30 days for
the presence of Leptospirae. The results obtained are as
follows :
1. 102 buffalo kidneys from 15 provinces were examined.
All Were negative.
2. 228 cattle kidneys from 15 provinces were examined.
None was positive.
3.
312 swine kidneys from 15 provinces were examined.
• Data were as follows :
PROVINCE
-
Ang Thong
Bangkok
Buri r a m
Cha C h o e n g S a o
Chiengmai
Khon Kaen
Lopburi
Nakhonpathom
Phi chit
Phitsanulok
Ratchburi
Roiet
Sakon Nakhon
Singburi
A l l w e r e i d e n t i f i e d a s L.
No.
OF
15
14
5
5
25
15
11
39
16
7
48
56
15
23
SWINE
No.
POSITIVE
2
6
3
1
1
3
i
X
I
4
2
pomona.
In 1962, with the co-operation of Veterinary Medicine
Department of S.E.A.T.O. Medical Research Laboratory in
Bangkok, an extensive survey was carried out throughout
— 41 —
the country. The serological test was the microscopic agglu
tination lysis test, using 18 live diagnostic antigens originally
supplied by W.H.O./F.A.O. Leptospirosis Reference Labora
tory at the Walter Reed Army Institute of Research. The
antigens are :
L.
L.
L.
L.
L.
andaman
pomona
ballum
alexi
australis
L.
L.
L.
L.
L.
baiembo
djasiman
canicola
grippotyphosa
borincana
Agglutinin
L.
N° tested
Percent Reactors
L. andaman
L. butembo
L. celledoni
L. bataviae
L. pomona
L. djasiman
L. hyos
L. autumnalis
L. ballum
L. canicola
L. ictero
L. pyrogenes
L. alexi
L- grippo
bori
L. wolffii
L. javanica
L. australis
L. celledoni
L. hyo,s
L. ictero
L. wolffii
rates among
L.
L.
L.
L.
animals.
BUFFALO
CATTLE
504
25
302
14
0.39
0.19
0.99
0.39
4.6
4.8
0.19
0.19
01.6
0.78
1.2
0.39
4.8
4 .
0.19
0.39
bataviae
autumnalis
pyrogenes
javanica
0.66
0.33
2.3
1.9
0.33
1.7
0.33
4
SWINE
171
7
5.2
0.59
0.59
0.59
2.3
2.6
0.66
0.33
Canine and rodent Leptospiroses have received some atten
tion in Bangkok, with the evidence of infection as shown
below :
Canine : L. canicola, L. bataviae, L.
autumnalis.
Rodent : L. javanica, L. bataviae. L.
icterohaemorrhagiae,
L. autumnalis, L. grippotyphosa,
L. hyos, L.
pyrogenes.
Leptospirae isolation from water.
— 42 —
Water from pond, canal and waterfall selected randomly
from various provinces of the country, revealed the presence
of the following leptospirae :
L. pomma,
L. autumnalis.
L. grippotyphosa,
L.
hebdomadis,
L.
bataviae,
L. javanica,
L.
L. butembo,
L. australis,
L. malaya,
M.
zanoni.
Diagnosis.
Leptospirae, unlike many bacteria, are not demonstrated
by the use of ordinary staining methods and usual micro
scopic examination. In an acute form of outbreak associated
with icterus, albuminuria, haemoglobinuria, anaemia and
abortion should be treated as highly suspicious. However,
even in positive cases, it may sometimes be extremely dif
ficult to demonstrate the organism in the blood, urine or
tissues, and transmission experiments using laboratory
animals are not always successful. Sub-clinical forms of
the disease seem to be the most difficult cases to diagnose.
In routine practice, a sample of urine is inoculated intraperitoneally into wealing hamsters. Death of the inoculated
hamsters between 4-21 days is considered as suspicious and
their kidneys are dark-field examined. Dark-field positive
kidneys are then cultured for the presence of leptospirae.
Control.
The control of Leptospirosis is a very complex problem,
because of the wide range of carriers from the domestic
rat and the dog as well as wild animals. New hosts and
new serotypes are being continually discovered. Again, the
presence of leptospirae in water has increased the degree
of complexity of control measures.
Sanitation measures can assist in the reduction of the
prevalence of infeciton to a great extent. Rat-destroying
programmes are very effective means in decreasing the
number of reservoirs. Education extension given to farmers
by survey teams, explaining the danger of the infection
also to h u m a n being, has led to voluntary co-operation
by farmers. This has subsequently and undoubtedly streng
thened the control measures.
Bull.
Off.
int.
Epiz.,
1 9 7 0 , 73 ( 1 - 2 ) , 4 3 - 4 8 .
Studies of Leptospirosis in Taiwan
(Republic of China)
by
Y. P. LIU (E, RYU) (*).
1.
—
Preliminary
in
domestic
survey
animals
of
in
Leptospirosis
Tahoan.
1. A preliminary survey of Leptospirosis in 1544 domestic
animals in Taiwan was carried out between November 1961
and October 1962 by the agglutination-lysis test. Serum
samples were taken from 583 cattle (491 dairy cows and
92 draft cattle), 501 swine (284 from the Taiwan Sugar
Corporation Hog farm and 217 from the slaughter house)
and 460 dogs (from N.T.U. Veterinary Hospital and Taipei
kennels).
2. Taking serum dilution 1 : 300 as positive, the results
were 13.5 percent (79/583) in cattle, 9.7 percent (49/501)
in swine and 21.7 percent (100/460) in dogs. Reactors with
positive results with serum dilution 1 : 1,000 were cattle
10/583, swine 1/501 and dogs 60/460.
3. As to the types of Leptospira,
cattle and swine were
mostly positive to L. icterohaemorrhagiae,
dogs were mostly
positive to L. canicola,
and neither cattle, swine nor dogs
were positive to L.
hebdomadis.
4. It may be concluded from this survey that in Taiwan
there are infections of domestic animals by L.
icterohaemor(*) H e a d a n d P r o f e s s o r , V e t e r i n a r y S c i e n c e D e p a r t m e n t ,
Agriculture, N a t i o n a l T a i w a n University, Taipei.
College
of
44
rhagiae,
tralis
L.
canicola,
L.
pomona,
L.
autumnalis
and
L.
aus
A.
2. — Isolation
of Leptospira
from
wild
rats
in
Taiwan-
The isolation of the leptospiral organism from 105 rats
captured in Taipei and its vicinity was attempted and 86 serum
samples from those rats were also used in the titre inves
tigation, using Schüffner-Mochtar's agglutination technique.
The results are summarized as follows :
1.
Of 86 serum samples, 20 (23.2 percent) showed positive
(1 : 300 up) reactions in serological tests.
2. The kidney tissue emulsions of 105 rats were cultivated
on Korthof and Fletcher's semisolid media (Difco) and,
as the result, leptospiral organisms were isolated from
11 rats' kidney tissue.
3.
A higher isolation rate was obtained by cultivating
1 : 500 — 1 : 1,000 tissue emulsions than 1 : 50 —
1 : 100 emulsion or fresh kidney tissue. Fletcher and
and Korthof media were equally good for the isolation
purpose.
4. No sexual difference in the rats was observed in so
far as the isolation rates were concerned. But the
isolation rate was higher in rats of larger size and
higher body weight. The reservoirs of the organism
among various genera were : genus Myocastor
coypus,
9 (27.2 percent) in 32 rats ; genus Rattus, 2 (3.3 percent)
in 61 rats ; genus Mus, none in 7 rats ; and genus
Apodemus,
none in 5 rats.
5.
Agglutination and absorption tests were carried out
on the isolated 11 strains of the leptospiral organisms,
and the results were 3 strains belonging to the L. aus
tralis A group and 8 strains to the L. javanica
group.
This is the first report proving the existence of those
two different leptospiral organisms in Taiwan.
3. — Leptospirosis
in man
and
rodents
on
Taiwan.
A survey on Leptospirosis in m a n and wild rodents in
Taiwan, by serological and cultural techniques, showed that
3.22 percent of 8,362 school children were positive by the
— 45 —
macroscopic slide-agglulination test of GALTON et al. The
number of positive reactions dropped to 1.94 percent when
the microscopic agglutination test was used. A group of
65 patients with illnesses suggestive of Leptospirosis was
studied. Ten (15.4 percent) were serologically positive and
in two (3.08 percent), L. canicola
was isolated by culture.
Of 586 rodents studied, 38 (6.48 percent) were positive
by the macroscopic slide-agglutination test and 20 were
positive by culture. R. norvegicus
was more often positive,
although this species represented only 32 percent of the
trapped population, and 18 of 193 (9.32 percent) animals
were positive. Only two of 282 (representing 48.5 percent
of the trapped population) R. rattus gave positive cultures
(0.71 percent).
Serotypes of leptospiral isolates were
tralis,
L. canicola,
L.
ausL. bataviae,
L. javanica,
and L. hebdomadis.
Isolation
canicola
from h u m a n beings and rats, and L.
bataviae
L. hebdomadis
from rats are reported for the first
of L.
and
time in Taiwan.
4. —
Leptospira
canicola
isolated
from
dogs
in
Taiwan.
Isolation of L. canicola
from two dogs establishes a source
of L. canicola in Taiwan. Two isolates were obtained by direct
culture of specimens of kidney suspension. Identification
of the two isolates as serotypes of L. canicola
was made
by cross-agglutination and agglutinin-absorption tests.
Two sera of five diseased dogs were serologically positive
and revealed a predominant titre of L.
canicola.
5. — Isolation
of Leptospira
from
stillborn
and aborted
foetuses
of swine
and wild
rats
in an animals
breeding
station.
1. 8 strains (21.05 percent) of Leptospira
were isolated
from the kidneys of 38 wild rats by the direct culture of
the tissue emulsion diluted in 1 : 500, 1 : 1,000, 1 : 2,000,
and 1 : 4,000 in Fletcher's medium containing 12 percent
screening tested rabbit serum.
Using the same method, two strains were isolated from
the liver and liver-kidney combined tissue emulsion of
swine aborted foetuses.
— 46 —
2. Better results were obtained when the emulsions of
liver and kidneys were in 1 : 2,000 and 1 : 4,000 dilutions.
Satisfactory results were not obtained by the direct culture
of a series of dilutions of swine urine specimens.
3. Of the 8 strains isolated from the wild rats, 5 were
studied for their serotypes by cross agglutination-lysis and
serum agglutinin-absorption tests. Three strains belonged
to L. javanica
serotype and the other two to L.
bataviae
serotype.
4. One of the two strains isolated from
foetuses of swine belonged to the L. javanica
the other to the L. canicola
serotype.
6.
—
A
study
in
on
the
Leptospirosis
breeding
the aborted
serotype and
infections
sow.
A preliminary study of Leptospirosis was carried out from
September 1966 to May 1967 on the Taiwan Sugar Corpo
ration Farm Animals Breeding Station. The SchüffnerMochtar agglutination-lysis test was used. The following
results of the serological survey were obtained.
1. In 409 sows and boars, 103 were detected as positive
to at least one of the leptospiral antigens and the agglu
tination-lysis titres were higher than 1 : 100 — 1,000 x.
The number of animals positive to L. canicola
was 52
(50.5 percent); 17 (16.5 percent) were positive to L.
ictero
haemorrhagiae
and L. canicola,
while only a few animals
were positive to L. pyrogenes,
to L. javanica
and to L.
pomona.
2. Among the 103 swine which were positive, 25 (23.1 per
cent) had once or twice produced still-born piglets or had
aborted at each pregnancy according to their clinical history.
The occurrence of still-born piglets and abortion was more
often in autumn than in spring.
3. Among an ordinary herd (non S.P.F. pig herd),
69.5 percent (16/23) of the boars and 46.5 percent (34/73)
of the two- or three-way crossbred sows were found to have
the highest susceptibility while among the S.P.F. herd,
no positive reaction was detected.
— 47 —
4. It may be concluded from this study that pigs on the
Farm Animals Breeding Station are infected by L. canicola ;
L.
icterohaemorrhagiae
pOmona.
7. — Studies
;
on
L.
pyrogenes
the susceptibility
to Leptospira,
;
L.
of water
javanica
;
L.
buffaloes
I.
Eight mature farming type Taiwan water buffaloes were
inoculated with L. australia
A, while six received L.
canicola.
Before inoculation, all the animals were negative to the
microscopic-agglutination test (agglutination-lysis test), using
the above species as antigen.
No sign of clinical Leptospirosis was observed,
four animals developed high temperatures.
although
Cultures made from buffalo blood, kidneys and urine
and from blood of guinea-pigs inoculated with kidney
emulsion and urine from the inoculated buffaloes were all
negative for leptospiral organisms.
Blood samples from the water buffaloes at 2, 3 and 4 weeks
post-inoculation were negative to the microscopic-aggluti
nation test except in the case of one of the animals. Blood
from this animal taken two weeks post-inoculation was
positive at 1 : 100 dilution with L. australis
A antigen but
samples taken at 3 and 4 weeks were negative.
8. — Studies
on
the susceptibility
to Leptospira,
of water:
buffaloes
II.
An attempt was made to isolate Leptospira
from the kidneys
of 103 water buffaloes in Taiwan. No positive results were
obtained.
During the 2 years' period from 1966 to 1968, 760 serum
samples from Taiwan water buffaloes were examined by the
microscopic agglutination test. At dilutions of 1 : 100 and
1 : 500, leptospirolytic action was observed in 13.9 percent
of the samples in 1966-67 and in 68.8 percent in 1967-68.
The microscopic agglutination tests for buffalo sera
obtained in Malaysia, Thailand and Taiwan were compared
following incubations at 28° C. and 37° C. Leptospirolytic
action occurred in the samples from each of these countries
— 48 —
and the tests at 37° G. showed a higher positive rate than
at 28° G.
Since the buffalo sera possess leptospirolytic properties,
the use of the present microscopic agglutination test is inadequate for the survey of agglutinin titre against
Leptospira.
Leptospirolytic properties of the buffalo sera from Taiwan,
Thailand and Malaysia were investigated and the results
were different. The strength of lytic reactions diminished
in the order of countries mentioned above.
***
REFERENCES
1. YOUNG ( S . S . ) , YEH (Y. C ) , SHENG ( Y . S . ) , HSIAO ( C . T . )
& WANG ( C . C . ) . — Mem.
Coll.
Agric.
Taiw.
Univ.,
1963, 7 (2), 123-129.
2. YEH ( Y . C . ) & YOUNG ( S . S . ) . —
Univ.,
1966,
8 (2),
Mem.
Coll.
Agric.
Taiw.
184-194.
3. FRESH ( J . W . ) , TSAI ( C . C ) , LAI ( C . H.) & CHANG ( C . T . ) .
Amer.
J. trop. Med. Hyg.,
1968, 17, 760-768.
4.
TSAI ( C . H.)
& FRESH ( J . W . ) . — J.
Formosan
med.
—
Ass.,
1969, 68, 58-62.
5. YUAN ( T . G . ) & Hou
( Y . S . ) . — Taiw.
Sugar
Corp.
Bulletin,
1967-68, 1-8.
6. YEN (G. C . ) & Hou ( Y . S . J . —
Series,
1968 (N° 62).
7. RYU ( E . ) & Liu
( C . K.).
—
/.
Cañad.
Agric.
J.
Ass.
comp.
China
New
Med.,
1968,
Med.,
1969,
3 2 , 447-449.
8.
RYU ( E . ) . —
14, 20-28.
/.
Taiw.
Ass.
anim.
husb.
Vet.
Bull.
Off.
int.
Epiz.,
1970, 73 ( 1 - 2 ) ,
49-58.
Rapid Microscopic Agglutination
Test For Leptospira Without
Non-specific Reaction
by
E. RYU (*).
INTRODUCTION
This Author has previously conducted an investigation
to determine antileptospiral titers of the water buffalo sera
obtained in Taiwan, Malaysia, and Thailand by means of
microscopic agglutination tests. In that survey it was found
that non-specific agglutination and lytic reaction occurred
frequently and such reactions took place more frequently
at 37° C. incubation than at 28° C. (1). It was proved later
that a lysis in non-specific reaction was due to the leptos
pirolytic property of a normal serum (2). Since the reaction
was also found in the sera of lower dilutions in other animals,
the accuracy of the conventional microscopic agglutination
test is not without question.
In general, the aforesaid microscopic agglutination test
requires a 3-hours incubation and a 100x magnified darkfield.
However, this Author while conducting an examination
under a darkfield illumination at 400x magnification has
found that, the microscopic agglutination of
Leptospira
occurred within 5 minutes at room temperature and the
reaction was accompanied with distinct morphological
changes of the organisms. Later on the test was employed
(*) D e p a r t m e n t of V e t e r i n a r y M e d i c i n e , C o l l e g e
of
N a t i o n a l T a i w a n U n i v e r s i t y , T a i p e i , T a i w a n ( R e p u b l i c of
Agriculture,
China).
— 50 —
on the sera of water buffaloes, yellow cattle, dairy cattle,
horses, swine and dogs. From each species more than
100 serum samples were used. The results proved that it is
a rapid method which is devoid of non-specific reaction,
dependable, and very practical.
MATERIALS AND METHODS
Filter papers of 1 x 5 cm. in size were prepared and
they were used as blood blotting-papers. Before being sub
mitted to test, such blood-blotted papers were put in test
tubes to dry at room temperature in order to destroy erythocytes. To prevent the growth of fungi, the test papers were
placed in a deep freezer operating at — 20° C. W h e n a long
distance shipment was necessary, the blood impregnated
papers were kept at room temperature for one n i g h t before
they were wrapped u p in either paraffin paper or vinyl
sheet and put in envelopes or boxes.
The sources of blood samples were : water buffaloes,
yellow cattle, and swine from slaughter-houses ; horses from
the Army Horse Breeding Farm ; dairy cattle from 7 dairy
farms ; and dogs from the Veterinary Hospital of the National
Taiwan University. The blood was collected from the tail
in dairy cattle, yellow cattle and water buffalo, and from
the cephalic vein in dogs.
Ten
L.
L.
L.
serotypes of Leptospira
canicola,
pomona,
javanica
L. autumnalis,
L. pyrogenes,
viz.,
L.
L.
L.
hebdomadis,
grippotyphosa,
L.
australis
A.,
L.
bataviae,
were used in this study. They were cultured
in Korthof's media at 28-30° C for 5-10 days. Under 400x
magnification there were at least 30 organisms per field. The
cultures of 2 weeks or older were not used because the
organisms tended to diminish and to lose their normal
contour.
The procedures of the rapid test were as follows :
1. From each blood-blotted paper a 1 cm. long portion
was cut and put into a test tube.
2.
1 ml. of Phosphate Buffer Saline (P.B.S.) was added
to the test tube to dissolve serum at 4° C. or at room-
— 51 —
temperature (below 22° G. )for 1 hour. The time was
shortened to 30 minutes whenever blotted paper became
white earlier.
3. The test tube was shaken well and 1 drop of its contents
was pipetted into one of the wells on a microscopic
agglutination test plate. Then a drop of antigen was
added to produce a mixture.
4. The plate was placed at room-temperature for 5 minutes.
5. A large loopful of the mixture was transferred to a
slide glass and covered with a cover slip.
6. The mixture was examined under 400x (ocular
objective 40x) magnified darkfied illumination.
10x,
A blotting-paper of 1 x 5 cm. in size could blot about
0.1 ml. of blood. Therefore, 1 c m of blotting-paper contained
0.02 ml. of blood and a 50x dilution was produced by adding
1 ml. of P.B.S. It was further diluted (100x) with an equal
amount of antigen : the serum was thus diluted to about
l00x. While 1 m l . of P.B.S. was added to 1 c m of blood
blotted-paper, the amount of serum-P.B.S. mixture was suf
ficient for r u n n i n g tests on 15 antigens.
2
2
RESULTS
W h e n equal amount of positive serum and antigen were
mixed at room temperature, morphological changes of
Leptospira
occurred immediately or in less than 5 minutes.
Such changes were clearly observed in a 400x magnified
darkfield. There were swelling and elongation of cells as
well as gathering of microbes. In the former, some micro
organisms were spherically swollen at one end. Faster lysis
of microbes was also noted, but complete lysis did not take
place. The agglutination of bacterial particles was its end
finding. Swelling and elongation were frequently found in
the canine sera while gathering of microbes was observed
in the sera of other species. However, rarely in a positive
individual canine serum these two types of changes were
observed when different antigens were used. In either
circumstances, the microbes reflected light due to their
increased refractive index. Also their movement was sus
tained throughout the initial stage of either category. The
— 52 —
reaction was considered positive when at least one swollen
or one microbial clumping was present in each
darkfield.
Leptospira
The results of this serological survey are summarized in
Table I. It indicates that the positive reactors in each animal
species were ; 9 out of 150 (6 percent) in water buffaloes,
1 out of 100 (1 percent) in yellow cattle, 37 out of 266
(13.9 percent) in dairy cattle, 3 out of 206 (1.50 percent)
in horses, 2 out of 188 (1.1 percent) in swine, and 15 out
of 121 (12.4 percent) in dogs. Blood samples of dairy cattle
were collected from 7 farms and no positive reactors were
found in 3 of them. However, from 1 farm half of the
positive reactors were detected. Two water buffaloes were
raised in this farm but their blood test result was negative.
TABLE I
Result
of
Rapid
SOURCE
SPECIES
Microscopic
NUMBER
Agglutination
EXAMINED
NUMBER
POSITIVE
Test.
TOTAL
NUMBER
POSITIVE
%
Water
buffalo
Abattoir
150
9
150
9
6.0
Yellow
cattle
Abattoir
100
1
100
1
1.0
36
30
46
48
57
29
20
0
3
14
0
0
5
266
37
13.9
206
3
206
3
1.5
22
80
86
0
1
1
188
2
1.1
121
15
121
15
12.4
Dairy
cattle
Farm
Farm
Farm
Farm
Farm
Farm
Farm
Horse
AHBF
Swine
Abattoir A
Abattoir B
Abattoir C
Dog
A
B
C
D
E
F
G
VH
AHBF = Army Horse Breeding
VH
=: V e t e r i n a r y
Hospital.
Farm.
15
j
)
)
— 53 —
Urine was collected from 8 positive dairy cattle reactors
and was inoculated into 2 guinea-pigs for each cattle. Five
days after the inoculation, the cardiac blood of these labo
ratory animals was cultured in Korthof's medium but no
microbes were obtained. Rapid microscopic agglutination
tests were run on their sera 3 weeks after the inoculation :
the results were also negative.
Table II shows the distribution of positive reactors against
10 serotypes of Leptospira.
It is noted that the sera of water
buffaloes reacted positively against 8 serotypes while the
numbers of serotypes agglutinated by other animal species
were : yellow cattle 1, dairy cattle 6, horses 2, and dogs 5.
When the frequency of serotype appearance is investigated,
in the dairy cattle it is in the following order : L.
icteroTABLE
Positive
Reactors
against
II
10 serotypes
of
« Leptospira
».
WATER
YELLOW
DAIRY
BUFFALO
CATTLE
CATTLE
HORSE
SWINE
100
266
206
188
25
1
0
19
0
0
•
DOG
SEROTYPES
NUMBER
150
1.
1
L. canicola
4
121
10
2.
1
1
3. L.
autumnalis
2
0
0
1
4.
L.
hebdomadis
0
19
0
0
5.
L. australis
4
1
0
0
6.
L.
pomona
3
0
0
0
pyrogenes
0
14
2 '
0
1
21
0
0
3
0
0
1
0
0
0
7
0
7
A
0
0
7. L.
2
8.
L.
9.
L.
grippotyphosa
.
7
bataviae
0
10.
_—
L. javanica
3
0
— 54 —
haemorrhagiae
; L. grippotyphosa
; L. canicola
and L.
heb
domadis
; L. pyrogenes
; and L. australis
A. And the order
in the dog is : L. icterohaemorrhagiae
; L. canicola
; L.
hebdo
madis,
and L. grippotyphosa;
and L.
pyrogenes.
DISCUSSION
The method of collecting blood on blotting papers has
been used by DUBAKIN (3), CHEN and SUITOR (4), and NOBUTO
et al. (5, 6) in their studies on Leptospirosis, Arbovirus
diseases, and swine Toxoplasmosis respectively. The dif
ference was that DUBAKIN placed a drop of blood on a strip
of filter. paper while this Author used the paper strip to
blot streaming blood. Such blood-blotted strips can be
preserved at room-temperature for 2 weeks provided that
fungal growth does not occur. If a longer period of pre
servation is needed, it is desirable to keep them in a deep
freezer because serum property may be affected.
Conventionally the microscopic agglutination test was
conducted at 22-37° C. (7), 30° C. (8), 32° C. (9) or 37° C.
(10, 11, 12). Since there was no fixed incubation temperature,
it seems that the temperature in this range would not cause
significant differences in the test.
The length of time used in the test was also variable.
Incubation times of 24 hours (13), 2-4 hours (9), 3 hours
(8, 10), 2 hours (7, 11), 30 minutes (14), and 12-15 m i n u
tes (15) have been used by m a n y workers. But it was
observed in this study that microbes swelled immediately,
or they agglutinated in less than 5 minutes. Thus, reading
the test result in 5-10 minutes would be most desirable
and in the meantime it could avoid non-specific reaction.
Positive reactions or agglutinations might scarcely occur
in more than 10 minutes but they are negligible because
of very low titers. Besides, non-specific reaction and spon
taneous agglutination tend to take place when serum and
antigen are allowed to react for a longer time. The reactions
of these sorts are thought to be caused by the leptospirolytic
action of normal serum which was reported previously (1).
In the present test two distinct, changes of microbes were
noted during antigen-antibody reaction. They were swelling
— 55 —
and elongation of bacteria and agglutination of bacteria.
The former was frequently observed in the sera of dogs
and occasionally in that of dairy cattle. Because more positive
reactors were detected from these two species, this type of
microbial change seems to be relative to their susceptibility
to
Leptospira.
When Tables 1 and II are reviewed, one will easily find
that there are a few sera which reacted positively against
a single serotype. Many of the positive samples were able
to agglutinate 2 or more serotypes. It might not be due
to dual, triple or multiple infections : however, it is about
right to think that the cause was isoantigenicity of serotypes.
YOUNG et al. (16) surveyed anti-leptospiral titers of cattle,
swine, and dogs and reported that the positive reactors
against Leptospira
at serum dilution of 300x to l,000x were :
13.5 percent in cattle, 9.7 percent in swine, and 21.7 percent
in dogs. They included dairy cattle, yellow cattle, and
water buffaloes in the category of cattle and did not specify
positive reactors for each species. For this reason their
result in cattle cannot be used for a comparison. After
conducting a serological survey of Leptospirosis in the
Swine Breeding Station of Taiwan Sugar Company, YEN
and Hou (17) concluded that 103 out of 409 sows (25.2 percent)
were positive reactors. Obviously these workers obtained m u c h
higher percentages of positive reactors in both swine and
dogs. In order to determinate whether their results were
due to non-specific reactions, comparative studies seem to
be necessary.
CONCLUSION
This
paper introduces a rapid agglutination test for
by means of examining 400x magnified darkfield.
The test could be completed in 5-10 minutes at room tem
perature and it could also eliminate non-specific reaction.
Leptospira
The microbial changes were clearly
course of this test and changes were of
there were swelling and elongation
another bacterial agglutination took
observable d u r i n g the
two types. In one type
of bacteria while in
place.
— 56 —
Because the blood is collected by the blotting paper method,
very small amounts were needed and the samples could be
easily handled or preserved. This method is particularly useful
when a long distance field survey is conducted.
The positive reactors in this serological investigation were :
6 percent (9/150) in water buffaloes, 1 percent (1/100) in
yellow cattle, 13.9 percent (37/266) in dairy cattle, 1.5 percent
(3/206) in horses, 1.1 percent (2/188) in swine, and 12.8 per
cent (15/121) in dogs.
The n u m b e r of serotypes agglutinated by each animals
species were : water buffalo 8, yellow cattle 1, dairy cattle 6,
horses 2, swine 2, and dogs 5.
ACKNOWLEDGMENT
The Author wishes to express appreciation to Dr. S . S .
for his assistance in the preparation of this study.
T.C.R.R.'s financial support to this study is also gratefully
acknowledged.
YOUNG
REFERENCES
1. RYU ( E . ) . — Studies on the susceptibility of water buf
faloes to Leptospira.
I I . W i t h particular reference to
the isolation of Leptospira
from kidney, the micro
scopic agglutination test and leptospirolytic action
of serum. J. Taiw.- Ass. anim.
Husb.
& Vet.
Med.,
1969, 14, 20-28.
2. RYU ( E . ) . — Leptospirolytic action of normal animal sera.
J. Mier. China.,
1 9 6 8 , 1 , 36-41.
3.
DUBAKIN
( N . I . ) . — Micro-agglutination test for leptospirosis on drops of blood dried on filter paper.
Veterinariya,
Moscow,
1963, 8, 74-75.
4.
CHEN
(W. F . ) & SUITOR ( E . C ) . — Utilization of the
plaque inhibition (P1) method to perform serological
—
identification
Hasb.
57 —
of arboviruses.
J.
Taiw.
Ass.
anim.
& Vet. Med., 1 9 6 8 , 1 3 , 4 1 - 4 6 .
5 . NOBUTO ( K . ) , HANAKI (T.), KOIZUMI (T.) & YONEMOCHI ( K . ) .
— Some aspects of natural infection of toxoplasmosis
in pigs. Nat. Inst. anim. Hlth Quart., Tokyo, 1 9 6 9 ,
9, 1 3 0 - 1 4 8 .
6 . MATSUI (T.), TOKUTOMI (G.), ONDA ( H . ) , KANBAYASHI (M.),
OKABE (S.), ITO ( K . ) , NOBUTO ( K . ) , HANAKI ( T . ) &
MATSUNO (T.). — Serologic survey of toxoplasmosis
in pigs at 2 3 0 slaughterhouses in Japan. Bull.
Publ. H l t h . , 1 9 6 7 , 1 6 , 1 1 2 - 1 1 9 .
Inst.
7. World Health Organization Technical Report Series
N° 3 8 0 . Current problems in Leptospirosis research.,
1967, p. 1 1 .
8. GALTON
(M.
M.),
NAHMIAS (A. J.)
MENGES
(R.
W.),
SHOTTS
& HEATH (C. W . ) . —
(E.
B.),
Leptospirosis.
Epidemiology, clinical manifestations in m a n and
animals, and methods in Laboratory diagnosis., 1 9 6 2 ,
p. 5 5 .
9. ALSTON (J. M.) & BROOM (J. C ) . — Leptospirosis in m a n
and animals., 1 9 5 8 , p . 1 8 6 , E. & S. Livingstone Ltd.
Edinburgh.
(S.). — Studies on Leptospira. I . Laboratory
technics for serological investigations. Proc. Jap. Acad.,
1 0 . YAMAMOTO
1957,
3 3 , 564-569.
1 1 . ROTH (E.), ADAMS (W. V.), GREER ( B . ) , SANFORD (G.
NEWMAN
( K . ) & MOORE
(M.). —
Comments
on
E.),
the
laboratory diagnosis of Leptospirosis in domestic ani
mals with an outline of some procedures. 65th Ann.
Proc. U. S. Livestock Sanit. Ass., 1 9 6 1 , 5 2 0 - 5 3 3 .
(S.), ASHIZAWA ( Y . ) & NAGATA ( Y . ) . — Studies
on Leptospirosis. I I . Experimental Leptospirosis in
Mongolian Gerbils. Jap. J. exp. Med., 1 9 6 2 , 3 1 ,
12. IMAMURA
399-403.
(E.). — Die Reaktionszeit u n d
Verwendung von Tottesten bei der AgglutinationLysis-Reaklion. Zbl. Bald. I. Orig., 1 9 5 7 , 1 6 9 , 2 6 0 - 2 6 8 .
1 3 . HARTWIGK ( H . ) & STOEBBE
— 58 —
14.
(J. S.). — Rapid slide agglutination by Leptos
piral antibodies. Med. J. Aast., 1955, 2, 161-164.
WANNAN
(A.). — Eine einfache Schnellniethod für die
Leptospiren-Agglutination. Z. ImmunForsch.,
1953,
110, 17-23.
1 5 . KRÜGER
16.
YOUNG (S.
S.), .YEH (Y. C ) ,
SHENG ( Y . S . )
A
HSIAO (G.
T.)
& WANG (C. C ) . — Preliminary survey of Leptospirosis
in domestic animals on Taiwan. Mem. Coll. Agric.
Taiwan, 1963, 7 , 123-130.
17. YEN (C. C.) & Hou (Y. S.). — A study on Leptospirosis
infections in the Breeding Sow. J. Agric. Ass. China.,
1968, New Series, N° 62 , 74-79.
Bull.
Off.
int.
Epiz.,
1970, 73 ( 1 - 2 ) , 5 9 - 6 5 .
Leptospirosis in J a p a n
by
Ryo YANAGAWA (*).
Epizootiological
in Japan.
study
of Leptospirosis
in domestic
animals
In Japan, Leptospirosis of the dog has been confirmed
since 1940 and mainly L. canicola and partly L. ictero
haemorrhagiae have been found to be the cause. The rate
of infection is particularly high in dogs in large cities,
and does not differ from that in other countries.
On the other hand, a cattle disease which is characteristic
of haemoglobinuria of unknown origin has been seen for
a long lime in the northern parts of Hyogo and Kyoto
prefectures each a u t u m n , and in 1950, the disease was
shown to be caused by leptospirae, L. hebdomadis
being
isolated.
From the results of a serological survey of sera from
recovered cattle, the existence of other types of leptospira
has been expected, b u t only L. autumnalis and L. australis
have been isolated from cattle in 1954 and 1956 respectively.
Thus, bovine Leptospirosis in these districts has been shown
as not being caused by a single type of leptospira.
Moreover, many cases of subclinical infection and abortion
due to Leptospirosis have also been reported. Although
leptospiral antibodies have been found in many horses
infected with periodic ophtalmia, no leptospira have been
(*) P r o f e s s o r , F a c u l t y of V e t e r i n a r y
kaido-Sapporo City, Holdiaido (Japan).
Medicine,
University
of
Hok
— 60 —
isolated from them. Only a few investigations have been
made in the pig.
With the above backgrounds and in view of the great
damage caused by Leptospirosis in various countries of
the world, a nationwide investigation on Leptospirosis was
carried out in Japan from 1956 to 1958. The following
is en account of the findings.
Distribution of Leptospirosis
antibodies
in domestic animals in Japan.
Serological investigation of leptospiral antibodies in domes
tic animals was carried out on a nationwide scale between
1956 and 1958. The investigation was very extensive and
the results are as follows :
A total of 12,396 domestic animals were examined :
6,845 cattle, 2,491 horses and 3,060 pigs. The following
6 types of leptospirae were used as antigen, namely ; L. ictero
haemorrhagiae,
L. canicola, L. autumnalis,
L.
hebdomadis,
L. australis and L. pomona.
The microscopic agglutination test was used and greater
than partial agglutination at a serum dilution of 1 : 300
or over was recorded as positive. The results are summarized
in Table I.
As shown in Table I, out of 6,845 cattle examined,
383 were positive at a titre of 1 : 300 and 287 at a titre
of 1 : 1,000 or over, i.e. 670 (9.8 percent of the cattle
examined) were positive. Positive cattle were found in
almost every prefecture throughout the country, but in
9 prefectures (Hyogo, Kyoto, Okayama, Shimane, Ehime,
Fukuoka, Kumamoto, Miyazaki and Kagoshima) the positive
ratio was higher than in other prefectures. That is, in general,
the ratio was higher in western Japan and not so h i g h in
eastern Japan.
The greatest number of positive cases was found for
and L. autumnalis,
accounting for
more than half of the total, followed by L.
hebdomadis,
L. australis, L. pomona and L. canicola in that order.
L. pomona was not isolated previously in Japan, but positive
reactors (in Okayama Pref.) were found among imported
Jersey cattle.
: 300
1 : 1,000
Ca
ü
OTHERS
DIFFERENT ANTIGEN
CO Ci
^
rH
i-t
T Í
H05C1
n
CO
G
H
vi
co r*- co co co o o o
T—1 T—1
cq m
rCO
CO COCTco
H
o o
co
OCOCîO
CO S I > ^
CT i-i i—I CD
CO COCTCi
CTCTi-i CO
co
co CÛ ce i>
CO LO
COCTCTCO
o
CO
CDCTCO CT
rH
LO r H O CD
O ï CD CTS
CO
Notes. — 1. W — L. icterohaemorrhagiae.
A
= L. autumnalis.
C
= L. australis A.
Ca = L. canicola.
B
= L. hebdomadis.
P
= L. pomona.
2. « Others » indicate animals which were positive at
the same titre to two or more types of leptospirae.
(9.8)
(21.6)
(10.9)
(12.5)
1
POS ITIVE
CS
670
536
334
1,540
(%)
EXAMINED
TITRE
E
2 ra
to
Cattle
Horses
Pigs
Total
SPECIES
No
POSITIVE
No
(1956-1958)
Result of serological survey of Leptospirosis in domestic animals
TABLE I
— 61 —
TH
CO
i—i r*
TH
irt CNCTCi
TO WCTt - -
j
T H CO CO LO
C 5 LO
LO
T-l
— 62 —
Among the positive cattle, animals showing symptoms
of the disease and confirmed as cases by isolating the causal
agent or by the serological reaction were found in Kyoto,
Hyogo and Shiga prefectures. Although Kyoto and Hyogo
prefectures have been known previously as areas with this
disease, this was the first time when the disease was defi
nitely diagnosed in Shiga prefecture, the outbreak being
found in an intensive dairy herd, and resulting in deaths
and in lowering of milk yields.
As shown in Table I, a total of 2,491 horses were examined,
out of which 536 or 21.6 percent were positive at a titre
of 1 : 300 or over, with more than half of the positive
horses showing an antibody titre of 1 : 1,000 or over.
A high ratio in the n u m b e r of positive horses was found
in Aomori, Ehime, Kochi, Miyazaki and Kagoshima prefec
tures, indicating that the positive rate is higher in western
Japan.
As in cattle, there were more positive reactions with
and L. autumnalis,
followed by
L. hebdomadis. However, although there were so m a n y posi
tively reacting horses, no definite disease symptoms have
been observed.
Of 3,060 pigs examined, 3 3 4 ( 1 0 , 9 percenti were positive
at a titre of 1 : 300 or over. According to prefectures, the
positive ratio was high in Aomori, Miyagi, Tochigi, Ishikawa,
Osaka, Okayama, Yamaguchi, Kagawa, Ehime, Tokushima,
Kochi, Oita and Miyazaki.
Accordingly it can be readily understood that the ratio
is high in the islands of Shikoku and Kyushu, but a high
ratio has also been found in some prefectures in eastern
Japan to some extent. Among the serotypes of leptospira,
was the most predominant, followed
by L.
autumnalis.
Study of the relation between age and antibody level
in cattle showed that at the age of 1-2 years few cattle have
any antibody, and that the positive ratio increases with
age. This is also true for the horse. In the case of pigs only
those one year old were examined, the positive ratio of
about 10 percent being found in the one-year age group.
— 63 —
The positive ratio was also high, though only in a small
number, in the adult pigs which had been raised as breeding
stock for a long time. Thus, the rate of leptospiral antibody
level increases with advance in age.
As stated above, the distribution of antibody in domestic
animals is widely found throughout the country, but the
number of cattle which show clinical symptoms is not
so large proportionally, and this occurs only in the limited
region of western Japan. Accordingly, the extent of the
actual damage caused by subclinical infection is u n k n o w n .
It has also been deemed necessary to carry out the serological
survey in wild animals in order to clarify the origin of
Leptospirosis in domestic animals.
Isolation
and identification
of
Leptospira.
Between 1955 and 1958, the isolation of leptospira from
the urine of 38 cattle showing haemoglobinuria in the north
ern part of Hyogo Prefecture was attempted and 21 strains
were recovered : 18 L. autumnalis,
2 L. hebdomadis
and
one L. australis.
The kidney and urine of 36 pigs and 33 cattle with positive
leptospiral serological reactions showed no particular clinical
symptoms, and the urine, kidney and ocular fluids of
23 horses (including 4 horses affected with periodic oph
thalmia) failed to reveal leptospirae.
In Japan, the isolation of L. autumnalis,
L.
hebdomadis
and L. australis in cattle predominates ; this finding may
be assumed as characteristic of Japan compared with other
countries.
District
heavily
infected
with
cattle
Leptospirosis.
The northern part of Hyogo Prefecture is known as a
district heavily infected with cattle Leptospirosis for the
last several decades and man is often involved with the
disease. The district is characterized by heavy rainfalls and
high humidity, with few clear days throughout the year.
Paddy field acreage predominates.
Haemoglobinuria caused by Leptospirosis occurs almost
entirely in September and October and the mortality rate
of affected cattle is estimated as about 24 percent. The
— 64 —
reservoir of leptospirae in this district has not yet been
clarified. Attempts were made to isolate leptospirae from
rats collected from grazing pasture of infected premises
and also to find antibodies in the sera of such rats, but
all were negative, nor are other reservoirs known. Thus,
the reason for the high incidence of Leptospirosis in this
district and the reservoir of leptospirae are still unknown
factors.
Investigation
on periodic
ophtalmia
in
horses.
Seventeen cases of periodic ophtalmia and 31 cases of
eye-inflammation in horses were investigated during the
same period in Miyazaki and Kagoshima prefectures.
It was found that the incidence of periodic ophthalmia
is concentrated in horses over 4 years old, and that a large
n u m b e r of horses affected with periodic ophthalmia were
serologically positive. Antibodies of L.
icterohaemorrhagiae
and L. hebdomadis were most common but there were also
some antibodies of L. australis and L. autumnalis.
Since
isolation of leptospirae was not made, leptospirae could
not be shown to be the causal agents of periodic ophthalmia
and eye-inflammation.
Diagnosis
and
control.
Field diagnosis is made by clinical observation but in
most cases, material is sent to laboratories where the diag
nosis is made by the serological test, and leptospirae isolation
is carried out. For this purpose, microscopic agglutination
is commonly used. Slide agglutination is rarely used. It
might be advisable to adopt the screening test by slide
agglutination because in the future, it will be necessary
to increase the number of antigens to be used.
In Japan, h u m a n beings in heavily infected districts are
vaccinated, but domestic animals are rarely treated. This
is largely because of the small amount of the infection
in cattle in the region, as well as the confusion in serological
diagnosis following vaccination.
Penicillin and streptomycin are widely used for treatment
and are considerably effective in causing improvements in
clinical symptoms. Leptospirae were no longer detected
— 65 —
in the urine of recovered cattle h u t extensive study is needed
to ascertain if all leptospirae are removed from the kidneys
by the treatment.
***
SUMMARY
In Japan, Leptospirosis was confirmed in the dog in 1940
and in cattle showing haemoglobinuria in 1950. A large
scale nationwide investigation of Leptospirosis in domestic
animals was carried out in 1956-1958.
1. Out of the 6,845 cattle examined, 670 (9,8 percent)
were positive at a serum titre of 1 : 300 or over. Antibodies
of L. icterohaemorrhagiae
and L. autumnalis were the com
monest followed by L. hebdomadis, L. australis, L. pomona
and L. canicola in that order. L. pomona which had not
been previously isolated in Japan was found in imported
Jersey cattle. From 8 cattle showing haemoglobinuria in
the northern part of Hyogo Prefecture, 18 strains of
L. autumnalis,
2 strains of L. hebdomadis and one strain
of L. australis were isolated.
2. Examination of 2,491 horses showed that 536 (21.6 per
cent) had positive reactions at serum dilutions of 1 : 300
or over. Although more than half the positive horses showed
a reaction at a serum dilution of 1 : 1,000, no clinical
symptoms were observed. The types of leptospirae in positive
horses were practically the same as in cattle. Periodic
ophthalmia of the horse was previously regarded as caused
by leptospirae, but in none of the 17 horses with periodic
ophthalmia and the 31 horses with eye-inflammation, could
Leptospirosis be clearly defined.
3. Survey of 3,060 pigs showed that 334 (10.9 percent)
were positive at serum dilutions of 1 : 300 or over and
the types of leptospirae causing the reaction were L. ictero
haemorrhagiae,
L. autumnalis
and few L. hebdomadis in
that order.
Bull.
Off.
int.
Epiz.,
1 9 7 0 , 73 ( 1 - 2 ) , 6 7 - 8 0 .
A Review of the Leptospiroses
of domestic animals in Australia *
(
}
Leptospirosis occurs in all the States of Australia and
studies on m a n , domestic and native animals have resulted
in the isolation of 20 serotypes in this country. Most of
these isolations have been made from man or native animals
in a small area of North Queensland where the epidemiology
of the disease has been intensively studied. However, four
serotypes have been recovered from domestic animals. These
are Leptospira pomona from cattle, sheep and pigs, L. hyos
from pigs, L. hardjo from cattle and L.
icterohaemorrhagiae
from dogs. Results of serological surveys reflect this limited
range of serotypes infecting domestic animals and suggest
t h a t infection with other serotypes is sporadic and does
not reach a significant level of incidence.
Leptospirosis is a disease of economic significance in cattle
and pigs.
In cattle L. pomona is the only serotype known to cause
clinical Leptospirosis but there is some suspicion attaching
to L. hyos in this regard. Economic loss results mainly
from death in calves and abortions in c o w s . Occurrence
of t h e disease is favoured by wet conditions which aid
transmission of infection presumably through contact with
contamined urine.
The acute form is seen mainly in calves. Clinical symptoms
associated with an acute haemolytic anaemia are evidence
during the leptospiraemic phase which occurs about one
Week after infection is initiated. There is fever, haemo
globinuria. anaemia and jaundice. Leptospires may or may
not be detected in the urine at this stage. Agglutinating
antibodies appear around 8 days subsequent to infection.
(*) P r e p a r e d b y officers
Industries.
of t h e Q u e e n s l a n d D e p a r t m e n t
of
Primary
— 68 —
Death may follow after an illness of 2-4 days. Post mortem
examination reveals anaemic changes, a variable degree of
icterus, dark or black kidneys and a bladder containing
dark red urine. Rarely, small necrotic foci are distributed
throughout the liver and peri-renal oedema may be
prominent.
Close observations of infected herds indicate that haemo
globinuria may be so transient as to not be observed under
farm conditions. In most animals which become infected,
localization of organisms in the renal tubules occurs and
leptospiruria starts 2 to 3 weeks post-infection and persists
for about two months. A chronic interstitial nephritis may
follow and lead to condemnation of the kidneys as « white
spotted » at abattoirs.
In adult animals, economic loss results mainly from late
abortions in cows. Recent experimental work (1) indicates
that the placental degeneration which normally occurs
during the latter stages of pregnancy allows intrauterine
infection of the foetus. After an interval of two weeks
during which the leptospires multiply sufficiently, foetal
death occurs through the foetal erythrocytes being haemolysed, and expulsion of the dead foetus follows. Thus
abortion occurs 3 to 4 weeks after infection. The abortion
itself is usually without special features but delayed expulsion
of the foetal membranes has been a common sequel in
some outbreaks, Leptospirosis is not regarded as a major
cause of abortion but spectacular losses can occur in indi
vidual herds.
Reports of Leptospirosis causing clinical disease in lactating
animals are infrequent. However, leptospiral infection has
been associated with a sudden and marked reduction in
milk production and the secretion of yellow blood-stained
milk without any physical abnormality of the udder.
Clinically, the condition has been termed a « flaccid
mastitis ».
Studies of the incidence of antibodies to L. pomona in
Australian cattle have yielded widely varying results. For
example one study recorded a 3.2 percent incidence of
pomona antibodies in New South Wales beef herds (2) and
—
69 —
another investigation on beef cows in North Queensland
beef herds indicated a 52 percent incidence (3). However,
in the cows which were the subject of the latter study
there was no correlation between titre and previous breeding
performances. This supports the generally accepted opinion
that the majority of bovine leptospiral infections are sub
clinical and overt disease occurs only under conditions that
are not fully understood. However, there i s . evidence that
generally an increased n u m b e r of reactors are found in
herds with clinical histories suggestive of Leptospirosis.
It should be noted that there is no general agreement on
what constitutes a diagnostically significant titre for Leptos
pirosis and investigators have regarded serum agglutination
titres varying from 1/30 to 1/300 as indicative of previous
leptospiral infection.
Laboratory confirmation of a diagnosis of Leptospirosis
may be performed most expeditiously by examination of
urine and sera from infected and in-contact animals.
Microscopic dark field examination of urine for leptospires
is facilitated by the addition of formalin to a concentration
of 0.5 percent (approximately). This method is as sensitive
as guinea pig inoculation for detecting leptospiruria. Unpreserved urine should also b e forwarded for a guinea pig
inoculation test to allow isolation or serological indentification of the organism involved. Leptospirosis m a y be
confirmed directly by culture of the organism from the
heart blood of an infected febrile guineapig or indirectly
by examination of guinea pig sera for agglutinating antibody.
From autopsy cases, pipettes of liver and kidney tissue and
formalin treated sections of these organs for histological
examination are valuable.
Examination of serum samples from a n u m b e r of animals
in a herd where Leptospirosis is suspected is useful since,
in an outbreak, a h i g h proportion of animals show h i g h
titres at the one time (1/3,000 or greater). A rise of titre
in an animal is indicative of current infection and this
can be checked if two blood samples are taken about two
weeks apart.
Residual vaccination titres may present a diagnostic
problem and the persistence of serum agglutinating antibodies
— 70 —
induced by vaccination of adult cows with a commercial
bivalent bacterin has been investigated at the Animal
Research Institute, Yeerongpilly, Queensland. Following
vaccination, agglutinating antibody was detected at 9 days,
reached a peak titre of 1/300 at about 25 days and gradually
declined to zero at 60 days post-vaccination. Revaccination
at this stage resulted in higher and more persistent titres.
Antibodies were detected at 4 days after this second vacci
nation and reached a peak titre of 1/3,000 at 11 days.
Titres of 1/100 were still detectable 4 months after the
second vaccination.
It has been noted that results of individual serum, agglu
tination tests for Leptospirosis may on rare occasions be
confused by the occurrence of a prozone phenomenon in
the early stage of the infection when the titre is increasing
in magnitude. For example, the initial screen test at. a
serum dilution of 1 /30 or 1/100 may indicate a negative
results while complete agglutination may occur at 1/300
and the final litre may be 1/3,000. The occurrence on this
phenomenon in leptospiral infections does not appear to
have been reported previously.
In areas where the cattle tick (Boophilus
microplus)
occurs, differential diagnosis of acute Leptospirosis from
Babesiosis on clinical grounds may present a problem.
Leptospirosis is most severe in calves several weeks of age
while Babesiosis tends to affect an older age group. A useful
clinical observation is that the febrile response in Leptos
pirosis is not as constant and prolonged as in Babesiosis
and calves with Leptospirosis frequently exhibit haemo
globinuria unassociated with increased body temperature.
, Streptomycin is the drug of choice for the treatment
of Leptospirosis and will prevent or eliminate leptospiruria.
A single subcutaneous dose of 1 gram/100 lb. is adequate.
When an outbreak occurs in young calves, the temperatures
of all in-contact animals should be recorded twice daily
and any calves with a body temperature above normal
treated promptly.
Sera submitted to veterinary diagnostic centres in Australia
for lepto,spiral survey or diagnostic purposes are most often
— 71 —
tested for agglutinating antibody to two serotypes, pomona
and hyos. Some testing for antibodies to hebdomadis
group
serotypes has been undertaken and more recently, the inci
dence of L. hardjo in Queensland has been investigated.
Significant serological cross reactions between pomona,
hyos
and hardjo do not occur.
Serological evidence indicates that the incidence of titres
to L. hyos approximates that of L. pomona. This serotype
has never been isolated from cattle. However, results of
serological tests and observations by field officers of the
Queensland Department of Primary Industries suggest that
L. hyos may be a cause of abortion in cows.
L. hardjo, a member of the hebdomadis serogroup, has
been recently isolated from Queensland cattle (4). There is
serological evidence of its presence in the Territories of
Papua and New Guinea. This serotype was first recovered
from cattle in the United States in 1960 and subsequently
from cattle in Canada and Italy. In these countries there is
field evidence that the organism may occasionally cause
abortion and mastitis in cows. Observations on infected
herds in the United States suggest that the bovine animal
is the reservoir host for this organism; that it is readily
transmitted between cattle but overt infection rarely occurs.
Significant data on the incidence of this serotype are avai
lable only for Queensland. Of approximately 15,000 sera
submitted to the Animal Research Institute, Yeerongpilly
over a two year period for leptospiral agglutination tests,
8.7 percent had hardjo titres of 1/100 or greater. This
represented a herd incidence of 14.8 percent. Experimental
infection of cattle with the Queensland strain resulted in
a milk disease syndrome characterized by fever and leptospiruria. Neither, haemaglobinuria nor abortion occured.
Cultural isolation of this serotype has been found difficult
and guinea pigs inoculated with the organism became
infected only irregularly.
Although the serotypes icterohaemorrhagiae,
grippo
typhosa, canicola and australis are known to cause disease
in cattle in other countries serological surveys have shown
that infection of Australian cattle with these serotypes occurs
only rarely. SPRADBROW (5) experimentally infected four
calves with an Australian strain of L. australis of h u m a n
— 72 —
origin. Clinically, there was fever and depression with rapid
and complete recovery. Leptospiraemia was demonstrated
on one calf. Antibodies were produced at only low titres
and leptospiruria did not occur.
Management
measures.
and
vaccination
are
the main
preventive
A number of farm management procedures are useful
i n reducing the spread of Leptospirosis. Pigs are commonly
carriers of leptospires. Therefore cattle, more especially
calves, should be kept strictly isolated from piggeries and
drainage. Since cattle can also remain carriers, calves should
be kept, segregated on clean, dry ground and not r u n in
the same paddock year after year. The disease can easily
be introduced with the purchase of cattle and pigs from
an infected property and therefore a serological test of cattle
and pigs before purchase is recommended as is vaccination
of introduced stock. As leptospires require moisture to
survive, muddy areas in lanes, yards and around water
troughs should be eliminated. Open dams also become a
potent source of infection as cattle often urinate d u r i n g
or immediately after drinking. Calf pens should be kept
dry and shelters exposed to sunlight at some time d u r i n g
the day.
Vaccination using a killed bacterin is widely practised
in areas where Leptospirosis is recognized as a problem.
A bivalent bacterin containing pomona and hyos antigens
is commonly used.
A vaccination programme recommended by the Queensland
Department of Primary Industries (6) is as follows :
Cows and heifers should be vaccinated around the time
of mating and again one m o n t h before the expected date
of calving. The initial vaccination should give protection
during pregnancy and vaccination prior to calving should
protect the calf through colostral antibodies and also give
a measure of protection to the cow. D u r i n g subsequent
pregnancies, a single vaccination one m o n t h before calving
is adequate.
In calves, colostral antibodies give protection u p to 4
to 6 weeks of age. For maintenance of immunity calves
— 73 —
should be vaccinated at this age. W h e n calves are vaccinated
at less than 3 months of age, they should be revaccinated
when they reach 3 months or within 4 to 6 weeks.
Previously unvaccinated cattle and susceptible cattle being
introduced into an infected herd should be vaccinated twice
with an interval of 4 to 6 weeks between vaccinations.
Ideally, this vaccination would be done before introduction.
Controlled trials of the efficacy of vaccination against
exposure to a natural L. pomona infection under Queen
sland conditions have shown that a single vaccination
afforted protection against both the acute form of the disease
with its manifestations of haemoglobinuria and death and
the severe chronic form characterized by nephritis and
illthrigt. Leptospiruria was almost entirely b u t not com
pletely suppressed. In this experiment vaccinated animals
either did not have leptospiruria or excreted only small
numbers for 1 or 2 days. In contrast non-vaccinated controls
constantly excreted enormous numbers of leptospires for
over 2 m o n t h s .
Likewise new-born calves which had suckled i m m u n e
mothers were protected against acute Leptospirosis. However
these calves had a transient leptospiruria at 6-8 weeks of
age probably resulting from decline of the passive immunity
acquired from colostral antibody.
It appears that the immunity provided by a single vac
cination may decline significantly by 5 m o n t h s post-vacci
nation. However, the protective effect of the vaccine persists
for several m o n t h s after the disappearance of serum agglu
tinating antibody.
From pigs L. pomona
and L. hyos
have been isolated.
L. pomona infection is sufficiently widespread to cause
an infertility problem of economic importance to the pig
industry in all Australian States and infected porcine kidneys
are a common source of laboratory isolations of this
organism.
Clinical signs of disease in the sow are limited to a mild
fever or may be absent b u t abortion, still-births and neo
natal mortality are common sequelae of infections occurring
— 74 —
during mid-pregnancy. Necrotic foci in the liver are a
characteristic finding in aborted piglets and leptospiruria
which may extend for months renders pigs an important
source of infection for calves and for m a n . Occasionally,
pale mottled pigs' kidneys, the sequel of leptospiral infection,
are seen at abattoirs.
Serological tests indicate that L. hyos is also widely dis
tributed. There is suspicion that hyos infection may occa
sionally result in an infertility problem similar to that
caused by L. pomona but definite experimental confirmation
of this is lacking.
The. incidence of leptospiral infections in apparently normal
pigs at a Brisbane (Queensland) abattoir has been examined
by cultural and serological methods (7). Culture of urine
of. 218 pigs resulted in the isolation of six strains of L. pomona
and one of L. hyos. Sera from 70 (36.5 percent) of 192 pigs
showed agglutinins to one or more of a battery of 22 antigens
with reactions to pomona and hyos predominating.
and L. canicola are important
pathogens of pigs in overseas countries but only 7 of the 192
sera tested in the above survey had agglutinins to ictero
haemorrhagiae. and none reacted to canicola.
Introduction of infected pigs constitutes the main source
of infection. Vaccination is commonly carried out as a
preventive measure. It is recommended that piglets receive
a primary vaccination at weaning. It is assumed that u p
to this age, their protection by colostral antibody has been
assured by vaccination of their dams. The primary i m m u
nization can be substantially reinforced by revaccination
after an interval of 6 weeks. Breeding sows, which have
been previously immunized should have their colostral
antibody reinforced by revaccination one m o n t h before
farrowing. Sows not previously immunized should be given
also an initial dose of 5 ml. before or at the time of mating.
However, it is strongly recommended that all sows used
for breeding purposes should have been previously immunized
as weaners.
is the only serotype which has
been recovered from dogs in Australia. There is serological
evidence that rare infections by a n u m b e r of other serotypes
may occur. SPRADBROW (1962) (8) found that of 150 apparently
— 75 —
normal dogs in the Brisbane area 11 (7.3 percent) had titres
of 1/100 against one or more serotypes.
has been isolated in Brisbane (9)
and in Sidney (10) on several occasions from dogs suffering
classical icteric Leptospirosis. Jaundice was the dominant
clinical and post mortem feature.
Epidemiological studies in Brisbane confirmed that sewer
rats were commonly infected" (11). It was concluded that
the s p o r a d i c occurrence of the disease in dogs was due
to the absence of dog to dog transmission and that infection
was contracted directly from rats.
The apparent absence of L. canicola from the Australian
canine population is surprising for this serotype does occur
in Australia and it is a common pathogen of dogs in other
countries. Thus the severe « renal fibrosis » which is
a common sequel of canicola infection is not seen in Aus
tralian dogs.
Sheep are relatively resistant to Leptospirosis but L. pomona
may cause haemoglobinuria, jaundice and death. Usually,
affected animals are found dead apparently from septicaemia.
Most of Australia's sheep graze in the drier inland areas
and only few outbreaks have been reported. L. pomona
has been incriminated as a cause of ovine Leptospirosis
in Victoria, Tasmania and Western Australia. Serological
evidence of infection of a flock of Queensland sheep with
a member of the hebdomadis g r o u p has been reported (12).
Equine Leptospirosis has not been confirmed in Australia.
There are overseas reports of Leptospirosis, in horses m a n i
fested by clinical symptoms resembling those of a mild
form of the acute disease in cattle. Abortion, and periodic
ophthalmia may follow. Serological investigations on farm
horses in the Victorian dairying area of Gippsland have
revealed the presence of antibodies to L. p o m o n a and
L. hyos (13). Examination of 100 equine sera collected in
New South Wales revealed antibody patterns that indicated
possible infection with serotypes of the pomona;
hyos,
australis,and
icterohaemorrhagiae
serogroups (14). In Aus
tralia there have been no reports associating periodic
Ophthalmia with leptospiral infection.
—
76 —
*
SUMMARY
Of the Australian leptospiroses, L. pomona infection in
cattle and pigs presents t h e major animal health problem.
Titres to L. hyos commonly occur in these two species
but there is no definite evidence that this serotype is a
pathogen. Titres to the hebdomadis
serogroup in cattle
probably represent infection with L. hardjo and again sub
clinical infection is the general rule. Sporadic L. icterohaemorrhagiae
infections occur in Australian dogs but
L. canicola is absent. In sheep and horses, Leptospirosis
is not recognized as a disease of any consequence.
A current Australian leptospiral serotype distribution list,
is appended.
*
REFERENCES
1 . MURPHY
1969,
( J . C . ) & JENSEN ( R . ) . — Amer.
30,
J.
vet.
2 . HUGUES ( K . L . ) , YOUNG ( J . S . ) & MOYLE ( J . G . ) . —
vet. J.,
Res.,
703.
Aust.
1968.
3 . DONALDSON ( L . E . ) , LUCAS ( M . H . ) , JOHNSTON ( L . A. Y . )
&. RITSON ( J . B.). — Aust.
vet. J.,
1 9 6 7 , 43, 4 1 .
4 . SULLIVAN (N. D . ) & STALLMAN (N. D.). — Aust.
1969,
vet.
43, 2 8 1 .
5 . SPRADBBOW ( P . B . ) . — Aust.
6 . DADSWELL ( L . P . ) . —
vet. J., 1 9 6 5 , 4 1 , 3 9 1 .
Qd. agric. J.,
7 . CHUNG ( G . T.). — Aust.
vet. J.,
8. SPRADBROW ( P . B.). — Ausi.
9. GRAY ( D . F . ) . — Aust.
1969,
95, 1 4 7 .
1 9 6 8 , 44, 3 1 5 .
vet. J.,
1 9 6 2 , 38, 2 0 .
vet. J., 1 9 4 0 , 16, 2 0 0 .
J.,
—
10. BOONE CR. D.). — Aust.
77 —
vet. J., 1952, 28, 81.
11. GRAY (D. F . ) . — Aust. vet. J.,
12. SPRADBROW ( P . B . ) . — Amt.
13. WELLINGTON
(N. A .
(W. J.). — Aust.
1942, 18, 2.
vet.
M . ) , FERRIS
J.,
(A.
1964,
A.)
40,
&
254.
STEVENSON
vet. J., 1953, 29, 212.
14. LEPHERD ( E . E . ) . — Aust.
vet. J., 1969 , 45, 46.
— 78 —
LEPTOSPIRES
ANIMAL
GROUP
SEROTYPE.
SUBSEROTYPE
ISOLATE
HOSTS
MAN
DOMESTIC
+
+
WILD
Icterohae
morrhagiae
Copenhageni
Mankarso
Javanica
Celledoni
Canicola
Canicola
+
Broomi
+
Bindjei
+
Melomys
Melomys
+
Isoodoon
macrourus
Rattus
rattus
Rattus
norvegecus
Rattus
conatus
Rattus
assimilus
Melomys
littoralis
Melomys
cervinipes
Uromys
caudimaculatus
Mus
musculus
+
Uromys
caudimaculatus
Rattus
conatus
Pgrogenes
Zanoni
Robinsoni
Celledoni
Zanoni
+
Dog
Rattus
norvégiens
Isoodoon
Rattus
Melomys
macrourus
assimilus
cervinipes
Isoodoon
Rattus
macrourus
rattus
littoralis
cervinipes
— 79 —
IN
AUSTRALIA
ANIMAL
GROUP
SEROTYPE
SUBSEROTYPE
HOSTS
MAN
DOMESTIC
Pomona
+
Pomona
Pomona
Australis
Australis
+
Bratislava
+
Grippotyphosa
Grippotyphosa
+
Hebdomadis
kremastos
Pigs
Cattle
Sheep
Peramelas
nasuta
Isoodoon
macrourus
Rattus
conatus
Rattus
assimilus
Rattus
rattus
Mus
musculus
Uromys
caudimaculatus
Isoodoon
Rattus
•
Mini
Medanensis
Szwajizak
+
+
Perameles
Hardjo
Tarassovi
(hyos)
hyos
Bakeri
WILD
macrourus
conatus
Perameles
Isoodoon
nasuta
macrourus
Isoodoon
Perameles
Isoodoon
Perameles
macrourus
nasuta
macrourus
nasuta
Cattle
Hyos
+
Pigs
Rattus
assimilus
Uromys
caudimaculatus
Hydromys
chrysogaster
Rattus
assimilus
Uromys
caudimaculatus
Hydromys
chrysogaster
— 80 —
A L P H A B E T I C A L L I S T OF S C I E N T I F I C A N D
OF L E P T O S P I R A L
SCIENTIFIC
Hydromys
NAMES
HOSTS
COMMON
NAME
chrysogaster
COMMON
NAME
A u s t r a l i a n w a t e r rat, Eastern.
Isoodoon
macrourus
Large northern short-nosed
Melomys
cervinipes
Fawn-footed, naked-tailed
Melomys
littoralis
S m a l l e r n a k e d - t a i l e d rat, little tree rat.
Mus
Perameles
Rattus
Rattus
Rattus
Rattus
Uromys
musculus
nasuta
assimilus
conatus
norvegicus
rattus
caudimaculatus
bandicoot.
rat.
House mouse.
Long-nosed
bandicoot.
Allied rat.
Canefield rat, D u s k y
N o r w a y rat, b r o w n
field
rat.
R o o f or black rat.
Giant naked-tailed rat
(Cape Y o r k U r o m y s ) .
rat.
Bull.
Off. int.
Epiz.,
1 9 7 0 , 73 ( 1 - 2 ) , 8 1 - 9 2 .
Leptospirosis in New Zealand
by
S. JAMIESON, R. M. DAVIDSON
and R. M. SALISBURY (*).
INTRODUCTION
Leptospirosis in New Zealand is not a new disease although
its diagnosis was confirmed for the first time in 1 9 5 0 (Anon.,
1 9 5 0 - 5 1 ) . « Red-water » in calves was a common and serious
disease prior to that time and there is little doubt that this
was due to leptospiral infection.
Interest in this disease syndrome was stimulated b y the
work of SUTHERLAND and SIMMONS ( 1 9 4 9 ) in Australia, where
they showed that haemoglobinuria in calves in that country
was due to infection with Leptospira pomona and the original
isolations in New Zealand have been recorded by SALISBURY
(1954)
and
SALISBURY
and
MCDONALD
(1955).
It is of interest to note that whilst KERSCHNER and GRAY
reported the presence of Leptospira
icterohaemorrhagiae and Leptospira canicola in rats and dogs in the
Dunedin area, DODD and BRACKENRIDGE ( 1 9 6 0 ) were able to
demonstrate that Leptospira icterohaemorrhagiae
was present
in calves with a clinical syndrome characterised by sudden
(1951)
(*) A n i m a l H e a l t h D i v i s i o n , D e p a r t m e n t o f A g r i c u l t u r e . P . O . B o x 2 2 9 8 ,
Wellington (New Zealand).
S. J . J A M I E S O N M . R . C . V . S . , P h . D , D.V.S.M.,
Division.
Director,
Animal
R. M. D A V I D S O N B . V . S C . ( Q l d ) , M.R.C.V.S., D.V.S.M,, V e t e r i n a r y
s o r y Officer ( I n f e c t i o u s D i s e a s e s ) .
R. M. SALISBURY B.V. S c . ( S y d . ) , D i v i s i o n a l
Veterinarian.
Health
Advi-
—
82
—
onset, loss of condition, dehydration, pendulous abdomens
resulting from a large accumulation of fluid, and death
within 2 4 - 3 6 hours. Jaundice Avas rarely seen. Infection
with Leptospira canicola, on the other hand, are extremely
rare and this is surprising in view of the high level of
infection in dogs in Great Britain, from whence a lot of dogs
are imported.
Leptospirosis in sheep
and to date all infections
The clinical syndrome
although the jaundice
has been recorded by HARTLEY ( 1 9 5 2 )
have been due to Leptospira
pomona.
is similar to that seen in calves
is not quite so intense.
The initial interest in Leptospirosis was as a disease of
calves and it was estimated that 1 0 percent of dairy farms
in Northland experienced outbreaks of redwater each year
(ENSOR, pers. comm.). This would be supported by the
fact of a total of 1 3 , 0 0 0 bovine sera examined over a period
of four years, approximately 1 0 percent gave a positive
reaction to the agglutination-lysis test for L. pomona.
It was. later shown by T E PUNGA and BISHOP ( 1 9 5 3 ) that
L. pomona could be the cause of abortion of cattle and later
a survey by MOLLER et al. ( 1 9 6 7 ) of 2 0 0 herds involving
1 8 , 0 0 0 cows in an intensive dairying area in New Zealand
showed that 1 1 percent of all abortions was caused by
Leptospirosis. Records over a two year period from the
Ruakura Veterinary Diagnostic Station, which services the
northern part of the North Island and includes the most
intensive dairying areas, indicates that in 1 6 percent of all
abortions where a definite diagnosis could be made was
due to. leptospiral infection (SHORTRIDGE, pers. comm.).
Leptospirosis has long been recognised as a disease of
pigs and the condition previously known as Swineherd's
Disease in Switzerland and Italy was later shown to be
due to leptospiral infection.
RUSSELL and HANSEN ( 1 9 5 8 ) in a routine survey of 1 , 1 2 5
sera from apparently healthy chopper-type pigs coming
to slaughter at nine different freezing works in New Zealand
found that 4 percent had titres to L. hyos at a dilution
of 1 : 2 0 0 or higher and 5 percent had similar L. pomona
titres. Whilst there is serological evidence of L. hyos infections to date no isolation of this serotype has been made.
— 83
—
As mentioned previously, in spite of the fact many dog
sera have been examined for the presence of L. canicola
antibody, no evidence of infection has been found (unpublished information). A recent serological survey of 6 7 police
dogs throughout New Zealand revealed that none were
positive to a variety of leptospiral antigens (Anon., 1 9 6 8 ) .
Several cases of Leptospirosis in dogs have been encountered
in which the clinical history and post mortem
findings
were typical of L. icterohaemorrhagiae
infection (SHORTRIDGE,
pers.
comm.).
There has been evidence of L. pomona infection in dogs
serologically and the organism has been isolated from a
dog housed on the same property where leptospiral abortions
were occurring in cattle. This is not surprising since dogs
have been known to eat foetal membranes.
Serological evidence of an infection in a cat with L. pomona
was reported by REES ( 1 9 6 4 ) and more recently the same
serotype was isolated from a cat by HARKNESS and SMITH
(in press). The possible significance of this finding and
infections in other animals Avili be discussed further under
epidemiology. There has also been evidence of infection
in the horse as denoted by positive serological examinations.
The n u m b e r of feral animals examined is not sufficiently
high to draw any firm conclusion, but in common overseas
findings, L. icterohaemorrhagiae
has been found in the rat.
SHORTRIDGE ( 1 9 6 0 ) showed that 8 out of 2 5 rats collected in
the same area where infections in calves were reported,
Avere positive and leptospira Avere seen in large numbers
in histological sections of a rat kidney. KIRSCHNER and GRAY
( 1 9 5 1 ) also showed the presence of L.
icterohaemorrhagiae
in rats in the Dunedin area, but no evidence of infection
was found in 1 8 3 rats collected in the Wellington area and
examined by BLAKELOCK and ALLEN ( 1 9 5 6 ) . DANIEL ( 1 9 6 6 )
examined 1 0 0 red deer sera against a battery of 8 leptospiral
serotypes and found 0 . 9 percent positive at 1 : 2 0 0 against
L. pomona and 0 . 9 percent suspicious against L. andaman.
A limited n u m b e r of opossum sera has also been examined
but was found negative.
Leptospirosis in domestic animals in New Zealand for
the period up to 1 9 5 5 was reviewed by MCDONALD (1955),
—
84
—
and whilst the basic position has not changed to any marked
degree since that time, evidence is now emerging that
serotypes other than those already mentioned may be present.
They in themselves may be of little significance from an
animal health viewpoint, but they may possibly be of importance in m a n ; and this will be referred to under the heading
of h u m a n infections.
Human
infections.
JOSLAND et al. ( 1 9 5 7 ) reported the results of a serological
survey involving the examination of 7 7 4 sera from a select
group of patients, most of whom were presented because
they had a « pyrexia of unknown origin » and in some
a tentative diagnosis of Leptospirosis had been made on
the basis of history and clinical findings. This survey
confirmed the presence of L. pomona, L. hyos and L. icterohaemorrhagiae,
which had previously been reported and
also indicated the possibility of infections with additional
strains capable of producing agglutinins against L. sertoli,
L. australia B, L. medanensis and L. autumnalis
AB.
More recent investigations carried out by the National
Health Institute under the guidance of the Inter-departmental
Committee on Leptospirosis have indicated that other serotypes
are involved. TILL et al. ( 1 9 6 9 , in press) has a total of 3 5 viable
isolates from h u m a n patient, 1 0 of which have been serotyped
as L. pomona, 2 as L. ballum and 4 as belonging to the
group hebdomadis, and the remainder has yet to be identified.
Leptospiral
serotypes.
Whilst L. pomona is the predominant serotype, it is obvious
therefore that other serotypes are involved, and since the
majority of h u m a n cases occur in people closely associated
with stock, particularly dairy cattle, the question immediately arises whether other serotypes than those previously
referred to occur in animals. Mention has already been
made to the fact that the majority of infections in all
animal species are due to L.
pomona.
occurs in calves in one area of
New Zealand and there is serological evidence of L. hyos
infections in pigs, although no isolations have ever been
made. In a recent survey (DE JONG, 1 9 6 8 ) involving 7 1 herds
— 85 —
and 893 animals; it was found that 54 herds showed evidence
of infection and 17 were negative. Of these 54 herds,
33 showed evidence of L. pomona infection only, 10 showed
L. medanensis
only and 1 L. icterohaemorrhagiae
only,
and the remainder mixed L. pomona, L. andaman, L. autumnalis and L.
medanensis.
It would seem therefore that L. medanensis may be playing
a primary rôle in leptospiral infections in cattle and later
work may show that this is in fact the serotype of the
sub-group hebdomadis
isolated by TILL (pers. comm.).
Whilst L. ballum has been isolated from m a n in this country,
there has as yet been no indication that this serotype occurs
in domestic animals. It is possible, however, that this
could be a rodent-man transmission since L. ballum was
originally isolated from mice.
Legal
responsibilities.
Leptospirosis is not included in either the 1st of 2nd
Schedule of the Animals Act 1967 so there is no obligation
to report the presence of disease in stock to the Chief
Veterinary Officer of the Department of Agriculture. Treatment and control is therefore the direct responsibility of
the practising veterinary profession. It is, however, in the
2nd Schedule of the Meat Regulations 1940 and any carcase
exhibiting lesions of Leptospirosis must therefore be
condemned for h u m a n consumption.
Leptospirosis has been a notifiable disease under the
Health Act since 1952, which requires that all h u m a n cases
be notified to the local Medical Officer of Health. Since
1965 it was also become obligatory for all veterinary
surgeons and veterinary laboratories to notify the nearest
Medical Officer of Health of any animal which they have
reason to believe is suffering from Leptospirosis.
Symptoms
and gross
pathology.
The symptomology and pathology of Leptospirosis has
been fully described in other publications. It is only necessary at this stage to summarise by indicating that L. pomona
infection in calves in this country normally follows the
pattern of high morbidity and mortality, high fever, icterus
— 86 —
and haemoglobinuria and this has been the pattern in lambs.
In cows a late asymptomatic abortion, accompanied by
uterine inertia and occasionally a mummified foetus would
arouse suspicion of Leptospirosis. Milking cows sometimes
show evidence of Mastitis.
infections in calves are evidenced
by rapid loss of condition, pendulous abdomen and are
usually fatal within 24-36 hours. Jaundice is rare. Most
pig infections are asymptomatic and should be considered
where abortions occur or when investigating deaths in very
young pigs.
Epidemiology.
The epidemiology of Leptospirosis is still far from clear.
It is known that most animals remain carriers following
infection and excrete leptospira in their urine for periods
r a n g i n g up to 100 days or more in cattle, and up to a
year in pigs.
However, the main factors influencing infection within
a herd and interherd spread have as yet not been fully
elucidated.
Whilst pigs with sub-clinical infections and shedding
leptospira have been incriminated in the spread of infection,
New Zealand experience over recent years would perhaps
suggest that they are not as important as was previously
thought. This observation is based on the fact that pigs
which were at one time run in close association with dairy
cattle and fed on pasture and dairy by-products, have been
halved in numbers over the last few years with the advent
of milk tanker collection on farms and a swing towards
dried milk products in dairy production. The incidence
of Leptospirosis has not fallen as a result, and if anything
has increased. Most cases occur on farms where pigs are
not raised. At the same time, there has been a marked
increase in dairy cow numbers and this has resulted in
cattle being run in closer association with each other.
Stocking rates in the intensive dairying areas is of the order
of 1.5 cows per acre. The handling of these large herds
without increased labour force has been made possible
by the introduction of the Herringbone dairy shed and
—
87
—
herds up to 150 head can be handled by one m a n and go
as high as 750 cows handled by four m e n .
We believe, therefore, the spread within herds is from
cow to cow by means of « carrier » cows and that leptospira
gain entry through the mucous membranes of the upper
respiratory and alimentary tract or through the conjunctiva
by urine whilst they are confined in the yards or in the
milking shed.
Under New Zealand conditions of grassland farming, it is
estimated that 5 percent of the total excreta is dropped
in the milking yard and that each 100 cows would excrete
50-100 gallons of urine in the yard per day. It will be
readily appreciated therefore that where there are a high
percentage of excreters, the opportunities for cross-infection
arc high under these conditions.
Having estimated that 5 percent of urine is deposited in
the yards and sheds at the time of milking, it would mean
that 95 percent is deposited on the pasture on which animals
are feeding, so no doubt infection could occur from grazing
contaminated pastures.
The survival of L. pomona outside, the animal body seems
to be related to an interaction of several factors, including
temperature, pH and moisture.
OKAZAKI and PUNGEN (1957) showed that temperature below
7° to 10° C. (44.6-50° F.) or above 34° to 36° (95.2 to 96.8° F.)
and a pH below 6.0 or above 8.4, were detrimental to survival,
and that they would survive for periods of up to 183 days
in supersaturated soil.
According to HANSON et al. (1964) the major factor in
the spread of Leptospirosis was close contact between animals
in a wet pasture environment. MUSAEI (1960) found that
the n u m b e r of properties having acid soil was l / 6 t h the
number of infected premises having neutral or alkaline
soil. These facts plus the knowledge that they will survive
for a comparatively long time in water, suggests that the
conditions prevailing on the average New Zealand farm are
ideal for the survival and transmission of leptospira.
Whilst between herd spread could result by the transference of infection by feral animals, dogs or cats, it is
— 88 —
more likely that this occurs as the result of introduction
of « carrier » cattle or per medium of water bovine infection.
There has been a marked rise in the n u m b e r of notifications
of the disease in m a n in recent years and it now ranks fifth
in order of importance. In one health district, of 212 cases
notified, 191 occurred in persons engaged in dairy farming.
Of those, 128 were from farms with herringbone sheds and
69 from farms with walk-through sheds. A recent survey
conducted by the Occupational Health Unit of the Department
of Health (unpublished) has confirmed that the incidence
of Leptospirosis in man working in herringbone sheds is
about twice as high as those working in conventional
walk-through sheds. The reason for this is that men are
working in a pit below cow level and so the opportunities
for urine splashing are so m u c h greater.
Control.
The disease in cattle can h e controlled by a continuous
vaccination policy whereby animals are vaccinated annually.
Unfortunately, this does not happen to any great extent
in practice because in the absence of clinical disease farmers
are inclined to lose interest in preventive vaccination procedures and it is only restimulated when clinical disease
reappears. Calves can be protected by vaccination of their
dams in late pregnancy (MCDONALD and RUDGE, 1957) and
in the face of an outbreak of Haemoglobinuria in calves,
in-contact calves may be treated with hyperimmune serum
(RUDGE, 1956).
Colostral
vaccinated
To control
cinated in
immunity lasts 6-8 weeks and calves may be
at about that age to confer active i m m u n i t y .
anticipated leptospiral abortion, cows are vacearly pregnancy.
Similar vaccination schedules can be used successfully
in sheep (WEBSTER, 1955) but as the disease in this species
is comparatively rare, little if any is practised.
Vaccination is also successful in pigs, particularly with
the bivalent vaccine available and is practised where the
disease is considered of sufficient importance to warrant
such measures.
Vaccination procedures are not inexpensive but it is considered that their application is worthwhile in the interests
—
89
—
of both animal and h u m a n health and that practising Veterinary Surgeons should stress this point to their farmer
clients.
In the light of recent experience it may well be that other
serotypes other than L. pomona and L. hyos should be
included in vaccines. There has been nothing to suggest
that L. medanensis produces clinical disease in animals but
it may be desirable to include this serotype in animal vaccines as a possible means of protecting m a n .
Discussion.
Leptospirosis is a disease of animals of considerable economic importance and one on which further work is required
particularly on cultural techniques and other diagnostic
methods, epidemiology and the « carrier » animal with
particular reference to those serotypes which do not cause
clinical disease in animals but may be pathogenic for m a n .
New Zealand farming methods and environmental conditions of temperature, rainfall and soil type are ideal for the
survival, and spread of infection and these conditions undoubtedly prevail in other countries enjoying a temperate
climate. Under systems of grassland farming where intensive
stocking is practised m a n is coming into closer contact with
his animals and is therefore himself at greater risk.
Control measures are available and these should be promoted more vigorously by the veterinary profession. Since
it is a disease of emerging importance in m a n there is
a need for closer co-operation between the veterinary and
medical professions at both research and field levels.
SUMMARY
Leptospirosis as a disease of animals in New Zealand is
discussed in the light of experience since the disease was
first diagnosed in 1950.
The majority of
confirmed cases of
Whilst it is a disease
red in pigs; sheep,
infections are due to L. pomona with
in calves only.
primarily of cattle, infections have occurdogs, eats and feral animals.
— 90
—
There is some evidence that other serotypes may be involved as high titres have been demonstrated against L. medanensis. Other serotypes have been isolated in man and because
the majority of infection in man arise as a result of his
close association with animals, this would suggest that perhaps other leptospiral serotypes exist in animals without producing clinical disease.
The epidemiology of the disease is discussed and whilst
this aspect requires further study, indications are that cattle
are infected as a result of their close association under New
Zealand farming conditions which are particularly suitable
for the survival and spread of the infective organism.
Evidence is presented of the growing importance of Leptospirosis as a disease in m a n , where the majority of infections occur in those engaged in dairy farming. Infections
in those working in herringbone sheds are twice as h i g h
as those working in conventional walk-through sheds and
is attributed to the fact that workers are more exposed to
urine splashing and spray.
Current control measures are referred to and a request
made that these should be promoted more vigorously in the
interests of both h u m a n and animal health.
REFERENCES
ANON. — N.Z. Depart. Agric. Ann. Rpt., 1967-1968, 24.
ANON. — N.Z. Depart. Agric. Anim.
1950-1951.
Res. Div.
Ann.
Rpt.,
& ALLEN (Rosemary E.). — A survey of
rats trapped in the Wellington area for Ectoparasites
and organisms of the salmonella, pasteurella and leptospiral groups. N.Z. vet. J., 1956, 5, 154-156.
BLAKELOCK ( J . H . )
R.). — Leptospirosis in pigs : Vaccination to control
perinatal deaths in piglets. N.Z. vet. J., 1964, 12, 17-18.
COOK ( B .
— 91 —
A preliminary survey of the incidence of
Brucellosis, Leptospirosis and Salmonellosis in Red
Deer in New Zealand. N.Z. J. Sci., 1966, 9, 399-408.
DANIEL ( M . J . ) . -
DODD
(D. G.) & BRACKENRIDGE (D. T . ) . — Leptospira icterohaemorrhagiae A.B. infection in calves. N.Z. vet. J.,
1960, 8, 1, 71-76.
(A.
HARKNESS
C . ) & SMITH
(B. L.). — In press, 1969.
(W. J . ) . — Ovine leptospirosis. Aust.
28, 169, 170.
HARTLEY
vet.
J.,
1952,
(Rosemary E.), CASHMORE (Suzan) &
(Heather M . ) . — Survey work on h u m a n leptospirosis in New Zealand. N.Z. med. J., 1957, 56, 128131.
JOSLAND ( S . J . ) , ALLEN
SCOTT
Kirschner
(L.) & GRAY ( W . G.). — Leptospirosis in New
Zealand. N.Z. med. J., 1951, 50, 342-351.
MC DONALD ( N . R.). — Leptospirosis in domestic animals
with special reference to the disease in cattle in Australasia. Vet. Rev. anot., 1955, 1, 117-120.
(N. R.) & RUDGE ( J . M . ) . — Prevention of leptospirosis in young calves by vaccinating their dams in
late pregnancy. N.Z. vet. J., 1957, 5, 83-92.
MCDONALD
MOLLER
(K.),
NEWLING (P. E.),
ROBSON (H. J . ) , JANSEN (G.
J.)
A.). — A survey of abortions and
long return intervals in dairy herds in the Huntly
district. N.Z. vet. J., 1967, 15, 137-142.
&
MEURAINGE ( J .
( M . A.). — Environmental factors influencing the
incidence of bovine leptospirosis. Veterinariya,
Moscow, 1966, 37, 22-25 (cited Vet. Bull., 30, 491).
MUZAEV
(L. M . ) . — Some effects of various
environmental conditions on the survival of Leptospira
pomona. Amer. J. vet. Res., 1957, 18, 219-223.
OKAZAKI ( W . ) & RINGEN
REES (H. G.). — Leptospirosis in a cat. N.Z. vet. J., 1964, 12,
64.
RUDGE
( J . M . ) . — The use of i m m u n e serum will prevent
calf losses from red-water in unvaccinated herds. N.Z.
J. Agric., 1956, 93, 354.
— 92 —
& HANSEN (N. R . ) . — The incidence of Leptospira hyos and Leptospira pomona infections in pigs
in New Zealand. N.Z. vet. J., 1958, 6, 50-51.
RUSSEL ( R . R . )
— Leptospirosis in New Zealand livestock.
Rev. sanit. Inst. J., 1954, 15, 2-12.
SALISBURY ( R . M . ) .
& MCDONALD (N. R . ) . — La Leptospirose
chez les animaux domestiques en Nouvelle-Zélande.
Bull. Off. int. Epiz., 1955.
SALISBURY ( R . P . )
(E. H.). — Leptospiral infection of rats.
med. J., 1960, 59, 558.
SHORTRIDGE
N.Z.
H.). — B o v i n e abortion caused by infection with Leptospira pomona. N.Z. vet. J.,
1953, 1, 143-149.
TE PUNGA ( W . A . ) & BISHOP ( W .
TILL ( D . C ) . — In press, 1969.
(B. A . ) . — Immunisation against
N.Z. vet. J., 1955, 3, 47-59.
WEBSTER ( W . M . ) & REYNOLD
Leptospira
pomona.
WEBSTER ( W . M . ) . — The hedgehog as a potential reservoir
of Leptospira pomona. N.Z. vet. J., 1957, 5, 113.
Bull.
Off.
int.
Epiz.,
1970, 73 ( 1 - 2 ) , 93-99.
Epidemiology, Diagnosis and Control
of Leptospirosis in Man
by
S. FAINE (*).
1. Clinical features
in
man.
The clinical form in which we see Leptospirosis in man
is often unlike the descriptions in textbooks published in the
English language, which are frequently erroneous. This is
because the classical description of Leptospirosis as Weil's
disease, about 80 years ago, was of a disease with jaundice,
fever, nephritis and an enlarged spleen. These features of
jaundice and haemorrhage are seldom seen in infections in
man nowadays. The typical doctor considers Leptospirosis
only when he sees a patient who has jaundice which he
hasn't been able to diagnose, and then perhaps looks for
laboratory confirmation. Those doctors who practice in areas
where Leptospirosis is common, such as in the northern
parts of New Zealand, and in Queensland, recognise clinically the disease as one where the manifestations are fever,
muscle pains, meningitis and some reddening in the eyes.
It is a disease rather like influenza. Thus, the first problem
is to educate medical practitioners to know the current clinical syndrome of Leptospirosis.
The second problem is to ask why the picture has changed.
One reason is that infection with L. icterohaemorrhagiae
is
not as common as it used to be. This is not just a relative
(*) P r o f e s s o r of M i c r o b i o l o g y , D e p a r t m e n t of M i c r o b i o l o g y , M o n a s h
University Medical School, Alfred Hospital, P r a h r a n Vic. 3181, Australia
—
94
—
change reflecting more diagnosis of infection with other
varieties of leptospira which were unknown 70 years ago,
it is an absolute change. Leptospirosis of the Weil's disease
type has become a rare disease, perhaps because we live further away from rats, and control pollution better.
Also, the factor of nutrition is very important. In some
areas of the world « mild » leptospiroses appear to produce
a slight and easily-treated illness in man. In other countries,
the same leptospires produce a very severe disease with liver
and kidney damage, and a considerable amount of haemorrhage. This is attributed to nutritional differences between
populations. It is necessary for doctors to be educated to
recognise that the manifestations of the disease will depend
on where people live, and what they cat and what sort of
leptospires they come in contact with.
2.
Epidemiology.
There are two separate sorts of epidemiological disease.
One may be called the feral type of disease, common in
South-East Asia, in parts of Europe, particularly Eastern
Europe, which may appear in either an endemic or an epidemic form. It is not uncommon in Eastern Europe for
people to encounter epidemics of Leptospirosis of a mild type.
This is because occasionally, due to climatic or other ecological considerations, the carrier rodent or marsupial population comes out of the forest or fields into contact with m a n .
Sometimes, floods drive these animals out of their nests.
Surface waters become polluted and infect m a n . This happens in rice fields, and in farms in Europe, where there may
be a sudden period of wet weather with suitable conditions
for the workers to become infected. There is also a second,
different picture, in the farm type of Leptospirosis where
the sources of infection for man are domestic animals, such
as cattle, sheep, pigs, and occasionally rodents associated
with them. Although rat populations on farms play a part,
the main sources of infection are domestic animals. This
type of infection is extremely occupationally directed, restricted almost entirely to those connected with handling
animals such as farm workers, veterinarians, butchers, abattoir workers. There is also an age distribution, with incidence confined to the age group that works with animals.
Occasionally, children or older people are affected on farms.
— 95 —
3. Serology
and
diagnosis.
There is a serological distribution which raises problems.
Changes in nomenclature are confusing for clinicians, epidemiologists and microbiologists. For example, L. mitili
(Johnson), later L. hyos, is now L. tarassovi.
is now restricted to members of a
rather rare division of the L. icterohaemorrhagiae
serogroup.
The correct name for the one which we all call icterohaemorrhagiae is now
copenhageni.
Only those
any locality.
are included
for detecting
serotypes which are tested for can be found in
It is necessary to ensure that all likely strains
in the batteries of antigens used in the tests
Leptospirosis by serological methods.
One main objective of tests is to identify and diagnose clinical cases. For this we need to know exactly which serological type it is — but first of all we need to k n o w whether
a patient or an animal has Leptospirosis or not.
Also, in serological screening procedures for epidemiological purposes, it is often important to k n o w whether there
is Leptospirosis present. The broad screening procedure is as
important as is a detailed diagnosis which will tell exactly
w h i c h of the serological types is present. Both procedures
have different purposes, and each its own application.
There have been many recommendations for
procedures which will be discussed below.
4 . Epidemiological
problems
in Australia and New
diagnostic
Zealand.
Leptospirosis in Australia is traditionally t h o u g h t to be
cane-cutter's disease of feral origin arising from bush animals, rodents or marsupials infesting sugar cane plantations.
It is said that there is very little Leptospirosis in m a n outside of this area. There is a high incidence in Queensland,
and it is easy to j u m p to the conclusion that because Queensland has sugar cane, this is cane-cutter's disease.
According to figures released recently (*), 73 of 148 cases
in man diagnosed in Queensland and northern New South
(*) A n n u a l R e p o r t of H e a l t h a n d M e d i c a l S e r v i c e s , S t a t e
s l a n d , 1 9 6 8 - 1 9 6 9 (1969) B r i s b a n e , G o v t . P r i n t e r , p . 73.
of
Queen-
—
96
—
Wales in 1968-69 were in industries connected with cattle,
dairy or meat industry. Only 11 (7 percent) were in the
cane industry. This means either the cane field Leptospirosis
situation has been improved very considerably by preventive
measures, such as b u r n i n g cane before it is cut, or there is
a much more intense interest in diagnosing infection in
people connected with the meat industry.
The size of the population at risk is not easily ascertained,
so that it is not possible to provide detailed statistics at present.
The incidence in man in New Zealand recently has been
very high in some areas. Infection appears to be confined
to occupational (farming) groups in some parts of that
country.
In New South Wales and in South Australia, serological
surveys at meat works have shown variable numbers up to
about 50 percent of the abattoir workers to have been infected. The herd incidence (serological reactors in cattle) may
be as high as 30 percent. Obviously people are becoming
infected, but how many of them have mild clinical illness
is unknown. Firstly, there are more diagnoses made than
there are actual notifications, although Leptospirosis is a
notifiable disease. Secondly, as mentioned above, unless the
doctors know what to look for they will not suspect the
diagnosis, nor ill they send serum specimens or try to make
isolations in culture, and laboratories w o n ' t have the information. There are no really reliable figures of the real incidence of Leptospirosis in m a n , even in areas where there are
high incidences in the cattle. Either our farming methods
are very good in those areas, or, our diagnoses are not very
accurate.
5. Serological
diagnosis.
Returning to the question of diagnosis, two separate requirements were mentioned above. One is specific diagnosis, for
which purpose the microscopic agglutination lysis test
(M.A.T.) is available. It is still the standard test against which
other specific tests are measured, although it is not perfect.
We need to know, using this type of test, what serological types are present in any local area. In addition to the
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97
—
list that was produced for Queensland (1), information from
South Australia (*) and from Victoria (**) shows that there
has been serological evidence of L. medinensis infections in
man, and also of bratislavia infections. These two serotypes
have only been included recently in the battery of test atigens.
The next problem is the screening test. The M.A.T. is not
good for screening because it is extremely sensitive. It crossreacts, it needs a highly specialised laboratory to do it and it
needs to have fresh special cultures grown all the time. Some
group screening antigen that will allow a confirmation or
negation of « Leptospirosis » is required. Several reports (2)
have appeared about the use of a biflexa strain (Patoc 1)
which cross-reacts with a large proportion of the other serogroups. Using this strain, it is possible to modify an i m m u n o fluorescence test as a screening procedure. There is need for
workers to use this test to ascertain its value. The antigen
may be preserved easily and the test can be done by any
laboratory where they can do immunofluorescence; this does
not require very complicated apparatus a n d can be performed with quite simple microscopic equipment. It is not perfect, but it is very m u c h better than n o testing at all. For
large numbers of tests, people might consider the use of an
automatic machine, such as one which is available for doing
the fluorescent treponema antibody test for syphilis, at about
five times as fast as manually.
The second type of test is a complement fixation procedure which could be m u c h more widely used for screening
purposes. It is relatively simple to use a leptospiral group
antigen included among antigens in routine virological
screening. A suitable antigen may be L. patoc i. Serological
surveys are necessary to know how m u c h Leptospirosis there
is, and screening procedures are required which will pick
up reactors in the first instance, so that the specific serotypes
can be identified later on.
(*) K i n d l y p r o v i d e d b y
{**)
Dr. K.
ANDERSON.
K i n d l y p r o v i d e d b y Dr. J . F O R S Y T H .
—
6.
98
—
Control.
The control of Leptospirosis in m a n is its control in animals, or the avoidance of contact with infected animal products. However, sometimes this cannot be done, and there
remain to be faced the problems of control among those
occupational groups whose work brings them into contact
with animals. The main concern is with domestic animals.
The methods available are firstly, better control of hygiene.
Secondly, mechanical protection (e.g., urine splash guards)
for people in « herringbone » milking sheds. Thirdly, eradication or Leptospirosis in domestic herds where people are
likely to become infected, so as to protect farmers and meatworkers.
Eradication needs first of all knowing where there is a
problem ; and secondly, immunisation or treatment. Immunisation is an important and controversial matter at present.
There is much debate over whether live avirulent vaccines
will prove to be more effective t h a n dead vaccines. It is clear
that live vaccines are safe and do not produce carrier states
themselves, but there is no good evidence about the protec
tive ability of the live compared with the dead vaccine.
Ideally, a vaccine would contain a purified protective antigen,
pan-specific, broadly immunising against all Leptospirosis.
It may not be possible, because so far no vaccine has been
introduced which will protect against a heterologous serological type, let alone one in a different serological group
A pan-specific or a multivalent vaccine active against several
types would be of great value.
7
Incidence.
In addition to surveys, a continuous surveillance programme is necessary to know the dynamic of the incidence
of infection, and of changes in incidence in different areas
due to climate, and to infection of herds by rodents. These
figures are necessary before a programme of control can be
planned. Also, and obviously, statistics must be based on proper surveys done with the help of reliable and competent
statisticians, consulted beforehand. Statistics should be based
not on the total general population, but on the population
at risk.
—
99
—
***
REFERENCES
1. Annual Report of Health and Medical Services, State of
Queensland, 1968-1969 (1969), Brisbane, Goot. Printer,
p. 73.
2.
TUENER
Soc.
(L. H.). — Leptospirosis. II. Serology.
trop.
Med. Hyg.,
1988, 62, 880-899.
Trans
R.
Point 6. — Maladies transmises par les tiques. Epizootologie,
Diagnostic, Prophylaxie.
Item 6. — Diseases transmitted by ticks. Epizootiology, Diagnosis, Control.
Punto 6. — Enfermedades transmitidas por las garrapatas.
Epizootología, Diagnóstico, Profilaxis.
Bull.
Off. int. Epiz.,
1 9 7 0 , 73 ( 1 - 2 ) , 1 0 3 - 1 0 7 .
Protozoan Diseases transmitted
by Ticks in India
by
C. Krishna RAO (*).
The pathogenic protozoa transmitted by ticks belong to
the genera : Anaplasma, Theileria and Babesia.
ANAPLASMOSIS
Anaplasmosis is a disease of cattle manifested by progres
sive anaemia associated with the presence of intraerythrocytic bodies.
Anaplasmosis has been reported from most parts of Africa,
Asia, Minor Asia, Southern Europe, Australia, South America, Taiwan, Philippines, Antilles and the Soviet, Union.
In India, occurrence of Anaplasmosis was first recorded in
1933 and since then the parasite, Anaplasma marginale has
often been recorded during routine examination of blood
smears of cattle. However, PATNAIK (1963) recorded 4 cases of
clinical bovine Anaplasmosis. SINHA and PATHAK (1966)
recorded A. marginale from Indian goats. Using capillary
tube agglutination test, MOHAN and PATHAK (1966) recorded
17 to 65 percent incidence of anaplasma infection in cattle,
buffaloes, sheep and goats.
Epizootiology.
In India, anaplasma infection is enzootic. Clinical infection
is extremely rare as calves pick u p the infection and become
(*) A n i m a l H u s b a n d r y C o m m i s s i o n e r w i t h t h e G o v e r n m e n t o f I n d i a .
— 104
-
premune. Imported animals, particularly adult cattle which
are more susceptible than calves, are liable to suffer from
the acute form of this disease.
Sheep and goats are susceptible but they develop mild
infection with A. marginale. Species such as antelope, zebu,
camel and deer are also considered to be susceptible to the
natural infection. Tick vectors of Anaplasmosis caused by
A. marginale reported from different parts of the world are
all species of genus Boophilus, some species of genera Dermacenter. Hyalomma,
Ixodes and Haemaphysalis.
Nothing
is known about tick vectors of the disease in India. No systematic work has been done on this disease in India where
it is not a major problem.
Diagnosis.
1. By symptoms and lesions.
2. By examination of blood. Examination of blood films
stained with various histochemical stains demonstrates anaplasma bodies.
3. Complement-fixation
test. Antibodies are detectable in
infected cattle beginning at 10 to 25 days following experi
mental inoculation. The test has been reported to be 96 percent accurate in detecting carriers. Purity of antigens, crossreactions between Anaplasma and bovine Eperythrozoon
and
the difficulties in performing this complex test are the factors
which have limited its use in practice.
4. Capillary-tube agglutination (CA) test. Anaplasma agglutinating antibody can be detected by means of the CA test.
The test is simple and easy to perform.
5. Fluorescence antibody (FA) test. The FA test is specific
but requires special sera and apparatus.
Control.
Therapy. Only the tetracycline series of antibiotics have
been shown to possess definite inhibiting effect on the m u l tiplication of anaplasma bodies. However, the usefulness of
the treatment is very limited as most of the damage has been
done by the time the disease is diagnosed.
— 105 —
THEILERIASIS
1. Theileria
annulata.
Tropical Theileriasis is caused by T. annulata.
It is characterised by pyrexia, malaise, anorexia, anaemia, icterus,
haemoglobinuria in some cases, digestive disturbances dyspnoea, swelling of the superficial and internal lymphatic
nodes, swelling of spleen and liver, lymphomata in the kidneys and a multiple localised ulcerative abomasitis.
The disease has been recorded from the Mediterranean
coastal countries of Africa and Minor Asia, Southern U.S.S.R.,
India, Pakistan and Western China. It affects cattle and buffaloes. Different species of ticks of the genus Hyalomma
are
vectors of this disease.
2. Theileria
mutans.
It causes benign infection characterised by pyrexia, anorexia and swelling of the superficial lymphatic nodes.
The infection has been recorded from Africa, North America, Asia, Southern Europe, England, U.S.S.R., Australia,
India and Pakistan. Tick vectors Rhipicephalus
evertsi
and
R. appendiculatus
have been reported from some countries
Recently work at I.V.R.I., India has shown H.
anatolicum
to be also capable of acting as vector of it.
Epizootiology.
Young ruminants are less susceptible and on contracting
the infection develop premunition.
Mortality in adult stock born and bred in tick-infested
areas is very rare. However, the stock introduced from infection-free areas suffer from acute form of the disease characterised by high mortality and morbidity. Mortality rate is also
dependant upon the virulence of the infecting strains.
Diagnosis.
2. By blood and gland smear examinations.
— 106 —
The carrier state of the infection can be revealed by either
subinoculating blood into susceptible animals or by splenectomy.
Control.
Although extensive field trials with several chemical compounds have been conducted, no satisfactory treatment of
clinical Theileriasis is known. Only tetracycline series of
antibiotics possess schizonticidal effect. As this stage of the
parasite precedes the onset of the clinical attack, then value
is limited only to the prophylaxis.
Advantage has been taken of the presence of less virulent
strains (e.g. Kouba strain) of the parasite, for immunisation
programme.
PIROPLASMOSE
1. Babesia bigemina. It causes « red water » and has been
reported from the Central and South America, Europe,
North, Central and South Africa, Australia, Pakistan and
India. Cattle, buffaloes and deer are susceptible to the parasite.
Tick vectors are the different species of the genus Boophilus,
some species of Rhipicephalus
and Haemaphysalis
punctata.
2. B. bovis. It affects cattle in Europe, U.S.S.R., and Africa.
Only one case of B. bovis infection in a buffalo has been
recorded in India. Tick vectors are Ixodes spp.
3 . B. argentina. This infection is common in India. Tick
vector is B. microplus.
Piroplasms
of sheep and
goats.
The parasites recorded from India sheep and goats are :
Babesia motosi, B. ovis, B. foliata, B. taylori. Some species
of ticks of the genera Dermacentor, Haemaphysalis and Rhipicephalus have been found to be vectors of these diseases.
Piroplasms
of
equines.
The parasites recorded from equines are : Babesia caballi
and Nuttallia equi. Both parasites occur in India. Different
— 107 —
species of ticks of the genera Dermacentor,
and Hyalomma act as vectors of the disease.
Piroplasms
of
Rhipicephalus
Swine.
The parasites known to occur in pigs are : Babesia trautmanni and B. perroncitoi. However none of the parasites has
been recorded from India.
Piroplasms
of dogs.
Babesia canis and B. gibsoni have been known to occur
in India. Rhipicephalus
sanguineus and Haemaphysalis
bispinosa respectively act as vectors of the two diseases.
Piroplasm
of fowls.
Aegyptianella
pullorum infection has been recorded
India. Argas persicus is the tick vector of the disease.
from
Epizootiology.
Piroplasmosis is enzootic in India. Young animals which
are less susceptible, contract the infection and recover.
Therefore, clinical infection in cattle reared in tick-infested
areas is noticed rarely.
Recovered animals harbour the infection for long periods,
may be for several years, but relapses caused by debilitating
factors and acute intercurrent infections debilitating are not
uncommon.
Diagnosis.
2 . By examination of stained blood smears.
Immunity.
Recovered animals develop durable premunity to the homologous strain of the parasite. The resistance may break down
under the stress of intercurrent disease or debilitating factors.
Control.
Effective treatments against individual parasites are available.
Bull.
Off.
int.
Epiz.,
1 9 7 0 , T3 ( 1 - 2 ) , 1 0 9 - 1 1 3 .
Diseases Transmitted by Ticks
in Thailand
by
Siri SUBHARNGKASEN
(*).
A tick-borne disease was first recognized in Thailand in
1953. At that time the Government, t h r o u g h the Army Veterinary Corps, Kasetsart University and the Department of
Livestock Development tried to develop a dairy programme
by importation of pure-bred stocks from abroad : Jersey,
Black and White and Brown Swiss cattle to up-grade the local
stocks for higher milk yield (Brown Swiss of Department of
Livestock Development was donated by the United States
Operation Mission to Thailand). These pure-bred stocks were
kept separately under the responsibilities of the three organisations mentioned above. A little while after the arrival of these
pure-bred animals, some deaths occurred among them and
the first recognition of a disease transmitted by ticks — Piroplasmosis — was made in the country.
Anaplasmosis is another disease transmitted by ticks and
it was first diagnosed in 1959 in Brown Swiss cattle, imported
from Switzerland. The second recognition was made in 1960
in Black and W h i t e cattle, imported from Hong-Kong and
the third case was reported in the same year in Red-Danish
Dairy cattle, of the Thai-Danish Dairy Farm, donated by the
Co-operative Farmers Association of Denmark to the Govern
ment of Thailand.
Bangkok (Thailand).
Development,
— 110
Why these pure-bred exotic stocks, imported from abroad,
got the infection is shown by experiments, given under heading of Piroplasmosis.
Piroplasmosis.
It will be advisable to mention in this report that the indigenous Thai cattle are highly resistant t o . Babesiosis. The
phenomenon could be demonstrated by the following experiments.
1st experiment. — A group of 7 indigenous Thai cattle, random selected, were kept at Pak Chong Breeding Station.
Close observation was undertaken for, ,7 days to assure the
general physical health of these animals, and the blood of
everyone was taken and examined microscopically for the
assurance of the absence of any organism before the experiment was started. The experimental animals were then splenectomized and their blood was examined microscopically
for protozoan parasites. The causal organism of Piroplasmosis, identified as Babesia bigemina, was found 3-7 days after
splenectomy.
2nd experiment. — A groupe of 4 cattle of different breeds,
random selected, were kept at Chieng Mai Breeding Station;
one indigenous, one 50 percent bred between indigenous and
Black and White, one 75 percent cross bred between indigenous and Black and White and the last one a pure bred
German Brown, donated by the Government of the Federal
Republic of Germany to the Government of Thailand, which
had been not less than 2 years in the country The procedure as well as the results obtained were the same as in the
first experiment.
It is obviously shown by thè previous experiments that t h e
Thai indigenous cattle are highly resistant to Piroplasmosis,
particularly caused by B. bigemina. The animals can harbour
quite a large number of parasites without showing any clinical
signs. They act as carriers indefinitely. The reason is how clear
why the pure bred stocks, previously mentioned got infected
a short while after their introduction into the country.
It was also noticed that a pure bred animal, e . g . G e r m a n
Brown, could acquire a high order of immunity when, it was
maintained in an enzootic area for a certain time. It is our
— III —
conviction that other pure bred exotic animals will also obtain
an acquired immunity as German Brown Swiss.
A survey of Piroplasmosis has not yet been carried out.
Babesia argentina was first recognised in 1965 when 5 pure
bred cattle died at Tap Kwang Breeding Station. It is strongly
believed that both B. bigemina and B. argentina are present
in the country and that B. bigemina is wider spread.
Diagnosis. — Tentative diagnosis is based on the symptoms : Fever, depression, loss of appetite, increased pulse
and respiration, anaemia and often icterus of mucous m e m
brane, milk yield dropped, abortion in some cases, haemoglobinuria. Definite diagnosis is based on the microscopic
findings of the organism, using Giemsa stain. B.
bigemina
can be seen easier than B. argentina under microscopic examination.
Control and Treatment. — A combination of the following
methods is used for control measures :
1. Direct destruction of ticks on cattle and on pastures by
using tick-destroying agents with brush, sponge, sprinkle
or hand sprayer.
2. Regular rotation of pasture for cattle to graze.
3. Double fencing at interval of 5 meters.
4. Destruction of the buffalo fly, as we do believe that this
insect acts as vector, spreading the infection. This theory
is supported by the following example : Australian Illawara
Shorthorn cattle imported from Australia were kept under
very good care and management. The pasture where these
animals were kept was cleaned from ticks. Many of t h e m
developed the disease at the same time with one death. The
other infected animals recovered after curative treatment was
given.
Curative treatment of sick animals is secondary compared
with control measures. 2 c.c. of 5 percent Acaprin per 100 kg
body weight is effective and i t is administered either subcutaneously or intramuscularly. Satisfactory results cannot be
expected if therapy is attempted after the animal has become
extremely weak, anaemic or prostrate. Supportive treatment
of the sick animal is also recommended to hasten recovery.
— 112 —
Anaplasmosis.
Anaplasmosis was first recognized in 1959. The recognition
was unintentionally discovered by the fact that Brown Swiss
cattle got infected with Piroplasmosis. Attempts were made
to save these valuable stocks by subcutaneous injection of
2 c.c. of 5 percent Acaprin per 100 kg body weight and all
of them were saved. About a fortnight later many of them
got infection this time of Anaplasmosis. The symptoms were
sudden rise in temperature up to 106-107° F, loss of appetite,
in some cases rumination stopped. There was also pronounced anaemia and the blood haemoglobin dropped to 3.00 gm/
100 c.c. but no sign of haemoglobinuria was noticed. Microscopic findings indicated the presence of Anaplasma
marginale. Death occurred among them whilst some of the survivors showed undesirable abilities for breeding purposes.
By co-incidental discovery led to the conclusion that Anaplasmosis co-existed with Piroplasmosis by which it was
camouflaged.
In 1964 five indigenous Thai cattle were splenectomised
under the supervision of Dr. R. V. S. BAIN of Australia, F.A.O.
Expert to Thailand. The presence of Anaplasma
marginale
was found in the blood of every head of cattle 7-16 days
after splenectomy. The experiment was repeated in 1969 with
the same result.
A survey for the incidence of Anaplasmosis was conducted
by using capillary tube agglutination test from 289 cattle and
688 buffaloes. The percentage of reactors in cattle and buffaloes was 37.37 percent and 2.33 percent respectively.
Diagnosis. — The tentative diagnosis is based upon : the
recognition of the symptoms of anaemia and icterus, the
history and knowledge of anaplasmosis-carrier cattle in the
area. A positive diagnosis depends upon the demonstration
of anaplasma bodies. In an infected area, the animals showing a drop in haemoglobin can be regarded as an anaplasmosis infection even if the blood smear is negative.
Control and
Treatment.
1. Pre-immunization with Anaplasma
the courtesy of C.S.I.R.O.
centrale,
given
by
— 113 —
2. Elimination of ticks as well as other blood sucker arthropods, some species of mosquitoes.
3. Curative treatment with tetracyclin of 5 m g / k g body
weight per day for 2-5 days depending upon the severety of
infection.
4. Blood transfusion
formed.
which has been occasionally
per-
Bull.
Off.
int.
Epiz.,
1 9 7 0 , 73 ( 1 - 2 ) , 1 1 5 - 1 1 9 .
Ticks and Tick-Borne Diseases
in J a p a n
by
Shigeo KITAOKA (*).
The species of ticks parasitizing cattle and horses had been
reported by NAKAMURA and
and NAMBA ( 1 9 6 3 ) . Other
YAJIMA ( 1 9 3 6 ) , ITAGAKI et al.
(1944)
fragmental data are also available
on this item, but they were too meagre to know the general
feature of distribution of tick species connected with the
local incidence of tick-borne diseases in Japan.
The author compiled the data on the tick species parasitizing on pasturing cattle based on the author's collection and
materials for identification sent to our laboratory throughout
the country excepting a few prefectures.
Although a considerable n u m b e r of species of ticks feed
on domestic animals other than cattle, there were no species
which transmitted tick-borne diseases. Anaplasmosis, Brucellosis and Leptospirosis are present in Japan, but no cases of
incidences of these diseases which would be caused by zoonotic function of ticks are reported.
Ten species of ticks belonging to 3 genera were recorded
among the known species of Amblyomma,
Boophilus,
Dermacentor, Haemaphysalis
and Ixodes in Ixodidae and Argas
and Ornithodoros
in Argasidae. Those ticks are Boophilus
microplus (CANESTRINI, 1 8 8 8 ) , Haemaphysalis concinna (KOCH,
1 8 4 4 ) , H. cornigera
(NEUMANN, 1 8 9 7 ) . H. flava
(NEUMANN,
(*) N a t i o n a l I n s t i t u t e of A n i m a l H e a l t h , M i n i s t r y of A g r i c u l t u r e
Forestry, T o k y o (Japan).
and
—
1 8 9 7 ) , Ii.
kitaokai
116 —
(HOOGSTRAAL, 1 9 6 9 ) , H. longicornis
(NEU-
MANN, 1 9 0 1 ) , H. sp. n . , Ixodies nipponensis
(KITAOKA et SAITO,
1 9 6 7 ) , I. ovatus (NEUMANN, 1 8 9 9 ) and I. persulcatus
(SCHULZE,
1 9 3 0 ) . There are no records of H. japonica
(WARBURTON,
1 9 0 8 ) and H. megaspinosa
(SAITO, 1 9 6 9 ) from cattle, which
were collected from horse and large-sized wild animals.
From the cattle of Okinawa islands, only B. microplus
was sampled within this survey. The species distributing
throughout the main four and adjacent small islands were
H. flava, H. longicornis and I. ovatus. Distribution of the
morphologically related two species, I. nipponensis
and
I. persulcatus, covered entire Japan, but the ranges of distribution of these ticks were segregated each other : I. persulcatus in Hokkaido and two focal areas in the central mountain range of Honshu and 7. nipponensis in the other southern
part.
The other haemaphysalids were found sporadically :
H. concinna in Hokkaido and the northern edge of Honshu;
H. cornigera in Hachijo and Miyake Islands; II. kitaokai in
central to southern Honshu and Kyushu; H. sp. n . in one
place near Mt. Fuji.
B. microplus is recorded in one locality of Shikoku, Kyushu,
Tsushima Island and Okinawa archipelago. Although there
were several old records on this tick in Honshu, the propagation in the present time is very questionable. H. falva and
I. ovatus showed thoroughly spread in distribution pattern,
the density of their infection on cattle was always relatively
low.
H. longicornis is the most prevalent species and the most
important tick as a vector of bovine theileriosis and babesiosis in Japan. KITAOKA ( 1 9 6 1 ) reported the existence of two
races of this tick which reproduce parthenogenetically or
bisexually. Two races of H. longicornis were found in different distribution areas having no distinct boundary : the
parthenogenetic population in Hokkaido and central to northern Honshu; the bisexual population in focal area near
Tokyo and central to southern Honshu, Kyushu and Shikoku.
Recently HOOGSTRAAL et al. ( 1 9 6 8 ) reviewed on this problem
with detailed description of the morphology, world distribution of II. longicornis and notion on taxonomically confused species, H. bispinosa.
— 117 —
According to their data, the parthenogenitic populations
were found in the Primorye area of U.S.S.R., Australia, New
Zealand, New Caledonia and Fiji and the bisexual one in
Korea. OLIVER and BREMNER (1968) studied on the chromosomes and sex-determining mechanism of ticks including
II. longicornis, and found the diploid number of chromosomes of the bisexual strain were 21 and 22 for male and female
respectively and those of the parthenogenetic strain were 31
to 32 as triploid n u m b e r . This result and the correlation between local incidence of piroplasmosis and feature of distribution of each pasture indicate that further taxonomic and
ecological research should be made.
Bovine theileriosis is a main tick-borne disease throughout
Japan and bovine babesiosis is found in far lower rate by
mixed infection with them in probably the same area. On
the other hand, tick fever by Babesia bigemina is restricted
in the range of Okinawa islands.
Theileria sp. in Japan has been identified as T. mutans
based on the superficial similarity of morphological characters within each species.
Ishihara and co-workers made comparative transmission
experiments using a considerable n u m b e r of strains of Theileria sp. originated in Japan, South Africa, Australia and
U.S.S.R. and several strains of various ticks of different
genera.
Table I is a summarized result on the vector-pathogenrelationship between ticks and various strains or species of
Theileria and Babesia. The Japanese strains of Theileria sp.
showed quite a resemblance in pathogenicity, to T. sergenti
YAKIMOFF and DEKHTEREFF (1930) which were severe than the
Australian strain of Theileria sp. and T. mutans was the
weakest. On the point of vector tick, the Japanese strains of
Theileria sp. is the same as T. sergenti and differ distinctly
from T. mutans and the Australian strain of Theileria sp.
each other.
The strains of B. bigemina in Okinawa, Formosa and
Korea were transmitted by three strains of B. microplus each
other. The Japanese strain of Babesis sp. was transmitted
transovarially by the two races of H. longicornis but not by
— 118 —
three strains of B. microplus. Therefore, Babesia sp. found
in Japan is a distinct species different from of B.
bigemina.
The isolated strain of Babesia sp. showed considerable
pathogenicity which is a little weaker than 73. bigemina to
adult cattle and splenectomized calves of the first infection.
Due to inhibition phenomenon. Theileria sp. on the multiplication of Babesia sp., the detection n u m b e r of Babesia
was low and the rate of discovery of babesiosis is correspondingly slight in pasture cattle.
Studies for the final identification is being carried out by
means of serological and cross immunity methods.
ci
Pi
s
/
/
S
/
/
/
/
ÍA
1 ^
longicor-
+
1
B. bigemina
(Formosan
Strain)
+ +
+
+
1
1
1
1
I I
+
1
—• Ticks did not transmit the piroplasma.
B. bigemina
(Japanese
Okinawa
Strain)
+
+ Ticks transmitted the piroplasma.
Theileria
SP.
(Japanese
Strain)
+
1
B. microplus
(Formosan strain)
I
microplus
(Japanese Okinawa
strain)
I
B.
Theileria
SP.
(Australian
Strain)
I
microplus
(Japanese strain)
+
B.
Babesia
SP.
(Japanese
Strain)
+
flava
(Japanese strain)
T. sergenti
(U.S.S.R.
Strain)
Piroplasma.
I I
H.
+
H- concinna
(Japanese strain)
Theileria
mutans
(S. African
Strain)
+
H. longicornis
(Japanese parthenogetic strain)
nis
(U.S.S.R. parthenogenetic strain)
H. longicornis
(Japanese bisexual
strain)
Haemaphysalis
Rhipicephahis appendiculatus
(S. African strain)
TABLE I
Vector-Pathogen-Relationship between Ticks and
(based on Ishihara's [1968] data)
— 119 —
Bull.
Off.
int.
Epiz.,
1970, 73 ( 1 - 2 ) , 1 2 1 - 1 2 9 .
Tick-Borne Diseases of Domestic
Animals in Australia (*)
1. Tick
Toxaemias.
W h e n feeding on animals ticks produce varying responses.
Usually the response is a local one and that caused by Boo
philus microplus has been described (1). However two species
can produce systemic effects. These are Ixodes holocyclus and
Omithodorus
gurneyi (2).
W h e n engorging as the adult stage 7. holocyclus females
can produce a flaccid paralysis in domestic animals and m a n .
Cats, dogs and sheep are more frequently affected but mortality has occurred in both young and fully grown cattle.
Experimentally, larvae and n y m p h s can be shown to produce
toxin but are of less consequence than engorging adults. The
eastern seaboard of mainland Australia and Tasmania is
infested, particularly where there is forest cover to provide
a habitat for the common hosts, Perameles spp. (bandicoots)
and other native animals.
The clinical signs are a curare-like effect with death following respiratory distress owing to paralysis of the muscles
of the thorax.
There is no abnormality to see at post-mortem other than
perhaps the presence of the tick or ticks. The only effective
treatment is the administration of h y p e r i m m u n e serum.
(*) P r e p a r e d b y officers
Industries.
of t h e Q u e e n s l a n d
Department
of
Primary
— 122 —
This is expensive. It is usually produced in the dog and used
only for the treatment of dogs and cats.
In the affected areas, domestic animals develop a strong
immunity if the initial doses of toxin are small.
Acaricide treatments aimed at preventing attachment of
the tick can be carried out but these need to be frequent and
the toxicity of the medicament to the host species may be a
consideration.
The disease can be controlled by clearing the land.
0. gurneyi, the inornate kangaroo tick is a soft, argasid,
tick. It is found at sites where kangaroos rest under trees
and in caves in the drier areas of North Australia and extending into New South Wales. There is evidence that after the
ticks have fed, the host kangaroos are very lethargic. Men
who have been bitten, subsequently had a few hours of impaired vision, headache and gastrointestinal upset (2).
2. Rickettsia
and Anaplasma
Infections.
Only two diseases are involved — Q fever of m a n , caused
by Coxiella burneti and bovine anaplasmosis.
N.B. The « Q » stands for query and not Queensland.
C. burneti has world wide distribution, with the exception
of Scandinavia and New Zealand. It occurs in Australia and
in fact was first recognised in this country.
Six Australian species of ticks have been experimentally
infected and excreta from such ticks has been found infective (3).
Transmission of the disease to man from ticks has not
been confirmed. The gravid uterus and m a m m a r y tissue of
infected animals (cattle, sheep and goats) are the important
sources of the infection but milk and m a m m a r y gland are
also involved. The bandicoot, one of Australia's marsupials
is a reservoir in the wild.
Meatworkers, fellmongers and veterinarians are the h u m a n s
most likely to be affected by the disease.
Anaplasma marginale is a parasite of the red blood cells
of cattle. The only known vector in Australia is the cattle
— 123 —
tick Boophilus microplus although blood sucking
Stomoxys
calcitrans and Tabania spp. flies are present. Therefore
A. marginale occurs only within the cattle tick area. This is
a coastal strip 100 to 150 miles in width extending from
Broome in Western Australia around the northern and eastern coast line of the Northern Territory and Queensland and
into the north east of New South Wales.
The incubation period is quite long being 2-6 weeks by
blood inoculation and presumably about 6 weeks for tick
transmissions.
Affected animals are fevered, anaemic and jaundiced and
have many of the red blood cells parasitised by the anaplasma.
These can be demonstrated as small dark dots in Giemsastained blood films. The post mortem findings are anaemia
and jaundice. The urine is usually normal in colour and this
is useful in differentiating anaplasmosis from babesiosis.
Most animals that are infected remain carriers of the infection and their blood can be used to transmit the disease to
susceptible recipients.
Tetracyclines are useful for treatment of the disease. These
drugs can be used at 2 m g per lb body weight for 2 or 3 days
to reduce the severity of the disease (4) but treated animals
often relapse 3 weeks to a m o n t h later. This relapse is not
as severe as the primary attack. Large doses, 5 m g / l b tetracycline given daily for 10-16 days have been used to eliminate the infection from cattle (5, 6).
A. centrale is less pathogenic and gives i m m u n i t y to
A. marginale.
Blood containing A. centrale is used as a
vaccine in areas where anaplasmosis has caused losses ( 7 ) .
Generally, there is a high level of resistance in endemic
areas and introduced animals are the greatest risk.
3 . Protozoan
Infections.
These include two babesia of cattle, one babcsia in the dog
and a theileria infection of cattle.
Babesiosis of
cattle.
Babesiosis is one of the most important diseases of cattle
in northern Australia. The two causative organisms are the
— 126 —
tina are attenuated prior to use by serial passage through
splenectomized calves (15). The vaccine is produced by inoculating a large dose of the strain of B. argentina in use
into a susceptible splenectomized calf. W h e n this calf has
a h i g h parasitaemia — usually after a prepatent period of 4
or 5 days — it is bled and given a transfusion by a carotid
canula. The following day the bleeding and transfusion operation is repeated. By estimating the percentage of parasitised
cells and the red blood cell count, the volume required to provide an infecting dose of 10 to 10 organisms can be calculated.
In order to produce a sufficiently large dose for inoculation
this is made up to a volume of 2 ml. This diluent is also
blood, normally from an uninfected animal but if B. bigemina or A. centrale are required it is taken from a carrier
of the appropriate organism.
7
8
Penicillin and streptomycin are added to the vaccine, it
is bottled as required and packed in a plastic bage of ice
that is placed in an insulated pack together with instructions
for use and advice on treatment. This vaccine has been
shown to be highly infective, and to produce mild reactions,
under field conditions (16).
The problem of producing a long lasting immunity by
vaccination is more complicated. Certainly one exposure to
babesiosis, whether by tick infestation or vaccination, is not
sufficient for life-long immunity. Further, field observations
suggest that in herds inoculated at 4-6 monthly intervals
with the one vaccine strain of B. argentina, solid immunity
may develop to that strain only, and that immunity to a
different (heterologous) strain introduced by ticks may not
be sufficient to prevent clinical disease (17). For this reason
the vaccine strain of B. argentina is changed at intervals of
5 months so that animals vaccinated at intervals of 6 months
will be exposed to and subsequently be resistant to a wide
variety of strains of B. argentina.
Another problem associated with the distribution of a
blood vaccine is the potential risk of spreading extraneous
parasites and other blood diseases. To ensure against the
spread of unwanted parasites, blood of vaccine donors is
screened prior to their use.
Recently it has been found that Under certain circumstances antibodies to vaccine red cells can develop to such
— 127 —
an extent that some breeding cows may have calves that
are fatally affected by haemolytic disease after taking colostrum (18). Further alterations to the vaccine are planned
to reduce the risk of this disease by reducing the red cell
content as far as practicable.
Canine
babesiosis.
In recent years Babesia canis infections were described in
North Queensland (12). Since then the disease has been diagnosed in other parts of the State. Young dogs are most severely affected and treatment with phenamidine isothionate is
effective.
There is some experimental evidence that
Rhipicephalus
sanguineus is the vector. It was present on infected dogs (19).
Bovine
Theileriosis.
The only theileria infecting cattle
pathogenic Theileria mutans. This
B. microplus in experimental (20)
areas occupied by this tick. The
transmitted by both Haemaphysalis
pinosa.
4. Infections
with
in Australia is the lowly
was not transmitted by
and extends beyond the
organism apparently is
bancrofti and H. bis-
Spirochaetes.
There are two tick borne spirochaetes that affect domestic
animals in Australia.
Borrelia theileri is a blood spirochaete of cattle. It can be
transmitted by the cattle tick B. microplus and apparently
some other ticks (21, 22). It is of low pathogenicity, producing only a mild febrile response for a few days.
Spirochaeta gallinurum
the cause of a severe disease in
domestic poultry is transmitted by the fowl tick Argas persicus and sometimes by the red mite Dermanyssm
gallinae (21).
The tick and the disease occur in the sub-coastal areas of
Australia and in farmyard flocks. W i t h intensification of the
poultry industry it has become rare.
Birds may die rapidly with the acute disease and present
a post-mortem finding of an acute toxaemia with a very
— 128 —
swollen spleen. Milder infections produce anaemia and jaundice with a yellow liver and swollen spleen.
Differential diagnosis depends on demonstration of spirochaetes in blood films or spleen by either Giemsa stain or
dark field illumination.
Prevention is by control of the vectors. A satisfactory killed vaccine has been produced.
*
**
REFERENCES
Tick Borne Diseases of Domestic Animals in Australia.
1. RIEK (R. F.). — Aust. J. agric. Res., 1962,. 13, 532.
2.
(H. R.). — Diseases of Domestic Animals in Australia. Service publication No. 7. Department of Health,
Canberra, A.C.T.
SEDDON
3. SEDDON (H. R.) & ALBISTON (H. E.). — Diseases of domestic
animals in Australia. 1965. Part 5. Service Publication
No. 10. Dept. of Health, Canberra, A.C.T.
4.
ANON. —
57th Annual Meeting U.S. Livestock
Sanit.
Ass.,
Med.,
1953,
1953.
5. SPLITTER (E. C.)
& MILLER ( J . G.).
—
Vet.
48, 486.
6. PEARSON (C. C.), BROCK (W. E.) &. KLIEWER (I. O.). —
Amer.
J.
vet. med. Ass., 1957, 130, 290.
7. LEGG ( J . ) . — Aust. vet. J., 1936, 12, 230.
8. DALY (G. D.) & HALL (W. T. K . ) . — Aust.
vet.
J.,
1955,
31, 152.
9. O'SULLIVAN (P. J . ) . — Unpub. Rep. Qd., Dep. Agric.
Files, 1960.
10. CALLOW ( L . L . ) & HOYTE (H. M . D . ) . — Aust.
1961, 37, 381-390.
11. REES (G. W . ) . — J. agric. Res.,
1934, 48, 427.
vet.
J.,
— 129 —
12. CALLOW (L. L.) & MCGREGOR. — Aust.
vet. J.,
1969, in
press.
13. HALL (W. T. K.). — Aust. vet. J., 1963, 3 9 , 386-389.
14. SEDDON (H. R.). — « Diseases of Domestic Animals in
Australia ». Part 4. Service Publication No. 8. Dept.
Health, Canberra, A.C.T. 1952.
15. CALLOW (L. L.) & MELLORS (L. T.). — Aust. vet. J., 1966,
42,
464.
16. DALGLIESH (R. J . ) . — Aust. vet. J., 1968, 44, 103.
17.
CALLOW
18.
BELL
(L. L.). — Pers. comm.
(K.) & DIMMOCK (Corinne). — In press, 1969.
19. HILL ( M . W . M . ) & BOLTON ( B . L.). — Aust. vet. J., 1966,
42,
84.
20. CALLOW (L. L.) & HOYTE (H. M . D.). — Aust. vet. J., 1961,
37,
21.
381.
(H. R.) & ALBISTON (H. E . ) . — Diseases of Domestic Animals in Australia. Part 5. Service Publication
No. 10. Dept. of Health, Canberra, A.C.T.
SEDDON
22. CALLOW (L. L.). — Brit. vet. J., 1967, 1 2 3 , 492.
Point 7. — Leucose aviaire —
Prophylaxie.
Item
7. —
Avian
Leucosis —
Epizootologie,
Epizootiology,
Diagnostic,
Diagnosis,
Prophylaxis.
Punto 7. — Leucosis aviar — Epizootología,
Profilaxis.
Diagnóstico,
Bull.
Off.
int.
Epiz.,
1 9 7 0 , 73 ( 1 - 2 ) , 1 3 1 - 1 3 2 .
Avian Leukosis in Thailand
by
Siri SUBHARNGKASEN (*).
Avian Leukosis was first recognized in 1949 when quite
a n u m b e r of pure-bred exotic birds (White Leghorn, Rhode
Island Red and Barred Plymouth Rock) were imported. Almost
two months after their arrival many of them got infection
which caused considerable losses. There was a difference in
the mortality rate and our experience was that resistance in
the Barred Plymouth Rocks was higher in the other two
breeds. The indigenous Thai poultry breed seems to have the
highest resistance to the disease.
Many forms of Leukosis have been reported since the first
case was diagnosed; Ocular, neural, viscera and osteoporotic.
The visceral form or what is also called hepatolymphomatosis is most frequently found. The frequency of Leukosis in
the year 1965-1969 are shown below :
YEAH
1965
1966
1967
1968
J a n . - A u g . 1969
No.
OF
BIRDS
EXAMINED
No.
OF
POSITIVE
20
22
30
39
15
177
171
32
48
19
Phya Thai Road (Bangkok).
CASES
Development,
— 132 —
Diagnosis.
Diagnosis is based on the symptoms as well as post-mortem
findings.
Ocular form — diffuse bluish-grey of iris, pupils frequently
become irregular in outline.
Neural form — paralysis of leg, wing, or less commonly
the neck. The disease may be unilateral or bilateral. The
unilateral is commonly found.
Visceral form — the liver generally is greatly enlarged and
the body cavity is full of fluid.
Osteopetrotic form — bone becomes swollen and dense. The
deformities can be seen by palpation if long bone is affected.
Control.
Careful culling of affected birds and separation of chicks
of different ages in separate pens are recommended.
Bull.
Off.
int.
Epiz.,
1970, 73 ( 1 - 2 ) , 1 3 3 - 1 3 5 .
Report on an Epizootic of Marek's
Disease in South Vietnam
by
Vu DINH CHINH (*).
INTRODUCTION
Marek's Disease is a highly contagious neoplastic disease of
domestic chickens, characterized by lymphoid infiltration in
peripheral nerves, the eye, skin, muscle and internal viscera.
Recently, a DNA virus of the herpes group has been incriminated. The disease is world-wide in distribution and probably occurs wherever large n u m b e r s of chickens are raised.
In some countries it causes great economic losses. In the
United States condemnation of carcasses due to Marek's
Disease cost an estimated 200 million dollars each year.
The fall of 1968 was the first time Marek's Disease occurred
in South Vietnam. W e believe that the first outbreak occurred
in October or November. However, the first specimen was
not received at our laboratory until early January. This flock
experienced a mortality of 30 to 40 percent, involving chickens from 3 weeks to 3 months of age.
It is believed that the disease entered the country d u r i n g
the massive imports of chicks, which took place during the
months of November, December and January. In one week
imports totaled nearly one half million chicks. Most of these
chicks (1 to 4 days of age) were imported from Singapore,
(*) Chief, B a c t e r i i n P r o d u c t i o n D i v i s i o n , N a t i o n a l
teriology and Animal Pathology, Saigon.
Institute
of
Bac-
— 134 —
Japan, Taiwan and the United States. The point of entry
was Saigon and most of the chicks were distributed in Saigon and surrounding provinces.
Clinical
findings.
Marek's Disease has been diagnosed in our laboratory in
more than 15 flocks. Paralysis of the extremities has been
observed in most of the flocks examined. The paralysis is
often assymetrical characterized by the drooping of one w i n g
or the vent feathers bent to one side. Muscular atrophy and
inscription was common. Large subcutaneous tumors can be
palpated in some specimens. They sometimes ulcerated and
become necrotic and secondarily to infected with bacteria.
In the plucked chicken, enlarged feather follicles could sometimes be observed. Only two specimens had the classic ocular
form (grey eye or pearly eye).
Necropsy
findings.
The distribution of lesions could easily be grouped into
nervous, visceral, skin and ocular forms. The brachial plexus
and sciatic nerve were routinely examined and occasionally
they were found to be greyish tan, enlarged and nodular.
The normal cross striated appearance was absent in affected
nerves. Gross changes in peripheral nerves were not frequently found as compared to lesions in other forms of the
disease.
In the visceral form of the disease, the liver, kidney, spleen,
heart, ovary, lung, and intestines, were frequently affected.
The tumors cut with ease and the cut surfaces were greyish
white and of uniform texture. The ovary was more frequently
affected than any other visceral organ. It was often found to
be greatly enlarged, smooth or nodular. The liver, spleen and
kidney contained similar neoplastic massess both diffuse and
nodular. In only one specimen was involvement of the thymus observed. The heart and digestive tract were seldom
involved.
Microscopic
findings.
Microscopic examination of affected tissues revealed massive infiltrations of lymphoid cells. Characteristic were mix-
— 135 —
tures of maturo large lymphocytes, lymphoblasts, a few
plasma cells and occasional « Marek's cells ». However, in
few specimens, lymphoblasts were predominate. The peripheral nerves were grossly affected, impression smears from
the cut surface revealed a similar population of cells.
DISCUSSION
Lymphoid Leukosis and related disease in the avian Leu
kosis complex are present in South Vietnam. However, the
mortality is relatively low (less than 5 percent). Also older
chickens, usually older than 4 months are affected. Marek's
Disease which causes relatively high mortality represents a
serious threat to broiler production in South Vietnam.
No program of control of this disease has been instituted
at this time. Selection of chickens for genetic resistance
to this disease as practiced in some countries, is not a realistic approach at the present time. Vigorous efforts at poultry management is suggested.
Bull.
Off.
int.
Epiz.,
1 9 7 0 , 73 ( 1 - 2 ) , 1 3 7 - 1 4 0 .
A v i a n Leukosis C o m p l e x in J a p a n
by
Takehiko SHIMIZU (*).
Incidence
of Avian Leukosis
Complex.
The Avian Leukosis complex is typified by Lymphoid
Leukosis and Marek's Disease from the standpoint of
actual damage. Out of these two diseases the damage from
Marek's Disease is more conspicuous in recent years in Japan.
Since it is not designated as an official disease, its epizootiological feature is not sufficient.
Although the acute Marek's Disease has not been observed
in Japan yet, it has been reported from the result of pathomorphological examinations on dead and cull chicks from
16,000 ones observed from 1 day to 12 months old during
the three-year period from 1960-1962 that about 4 percent
of them have died from lymphomatosis and out of which
75 percent were classified as visceral lymphomatosis and
25 percent were neural lymphomatosis.
Major portion diagnosed as visceral lymphomatosis is judged to fall under Lymphoid Leukosis and major portion diagnosed as neural lymphomatosis as falling under the classical
form of Marek's Disease. Since then, commensurate with
the increase in imported chicks since 1965 the increase of
lymphomatosis has been witnessed in young bird and the
damage therefrom is estimated to be very h i g h .
(*) N a t i o n a l I n s t i t u t e of A n i m a l
and Forestry, Tokyo (Japan).
Health,
Ministry
of
Agriculture
— 138 —
Since the fall of 1968 a large scale investigation on the
incidence of Avian Leukosis complex is being carried out
under the guidance of the Bureau of Animal Industry of the
Ministry of Agriculture and Forestry and according to interim report thereof, in 42 chicken groups of 22,427 chickens
observed from the age of 51 days to 120 days, 1,358 chickens
(6.1 percent of the total chickens) have died or discarded,
out of which 748 chickens (3.3 percent of the total chickens
and 55.1 percent of dead chickens) have been diagnosed at
the post-mortem inspection as lymphomatosis.
And the compositions thereof were 694 cases
involved only in the visceral organs, 165 cases
lesions only and III cases with lesions both in
organs and nerves. Major portion of the cases
lesions as well as of the cases with lesions in
organs can be judged as acute Marek's Disease
of ages involved.
Distribution
of
with lesions
with neural
the visceral
with neural
the visceral
in the light
Agents.
As stated above in Japan the damage on young bird from
lymphomatosis is high and the major portion is judged as
acute Marek's Disease. Most recently from the lesion of chicken infected with such disease cell associated virus of the
Herpes group have been isolated at considerably h i g h percentage and it has been estimated that this agent has been
distributed to a considerably a wide area. However, it has not
been clarified whether or not these cell associated viruses
are all antigenically uniform and the systematic investigation
in this field has not yet been launched.
On the other hand, the characteristics of Avian Leukosis
virus which is the pathogen of Lymphoid Leukosis has been
clarified and the research method has practically been established. The result from the serological investigation on
514 cases of chicken sera collected from 8 prefectures from
various regions showed that practically no regional difference has been witnessed as a whole. And in an average
around 50 percent of the sera were positive against the Agroup virus and around 10 percent against the B-group virus
respectively. It has been made clear that the A-group virus
played the lead in transmission.
— 139 —
Another investigation on the susceptibility and the existence of viruses was subjected to 180 cases of fertilized eggs
from 5 chicken farms under the RIF test. Most of the
layers are characterized by phenotype of C/O (64 percent)
and C/B (32 percent) but in the case of broiler phenotypes
of C/A and C/A, B have been found over 20 percent. The
fact that phenotype of C/B is larger as a whole can be j u d g ed as one reason for the low infectivity of the B-group virus.
Furthermore, it has been discovered that among those
eggs 2 cases harbored the A-group virus and 1 case the
B-groupe. From this fact that there is egg transmission,
although the rate is low, it indicates heavily infected chick
hatched therefrom may play a major source of transmission.
Problems
in
Diagnosis.
Because acute Marek's Disease does not always follow the
pattern of disturbing peripheral nerves, differential diagnosis
with Lymphoid Leukosis is rather difficult. So the development of a simple specific method of diagnosis is desirable
which can be used in the field against each disease.
It has been expected that the direct attestation of specific
antibody of tissue lesion under the Cofal test will serve as a
diagnostic method of Lymphoid Leukosis, but as the method
of HUEBNER et al. using antiserum of hamster may show nonspecific reaction, it can not be applied in the field.
In this respect, the method using pigeon antiserum developed by SAZAWA et al. is highly specific and preferable
because it completely does not react to normal avian tissue
antigen. Since the Cofal test itself is the reaction due to internal component of virus common to Avian Leukosis virus as
antigen. Special attention shall be paid to the fact that a
chicken heavily infected such as tolerant infection may react
as positive even if it has not yet developed the disease. At
present, the diagnostic value of this method is being studied.
*
— 140 —
SUMMARY
In Japan the Avian Leukosis complex is not designated as
an official disease ; therefore, the incidence thereof has not
been clarified authentically.
From 1965 the import of chick has markedly increased
and commensurate therewith the increase of lymphomatosis
in young bird (acute Marek's Disease) came to be observed
and at present great damage is being inflicted by this disease.
Recently, cell associated virus of the Herpes group has Peen
found in chickens infected with the disease in h i g h ratio.
However, the antigenicity has not been clarified and the
research thereon is being continued.
The Lymphoid Leukosis incidence is being witnessed throughout the country and the A-group virus is judged to be
a major transmitter. In the investigation under the RIF test
the phenotype of C/B is found to be larger in number. As
for the method of diagnosis for Lymphoid Leukosis the
method using pigeon antiserum developed by SAZAWA et al.
is judged to be better than that of HUBNER et al. and studies
are being conducted on the diagnostic value.
On the other hand, the research to establish the resistant
line by genetical selection will be launched this year at the
National Livestock Breeding Stations with the cooperation of
the National Institute of Animal Health.
Bull.
Off.
int.
Epiz.,
1970, 73 ( 1 - 2 ) , 1 4 1 - 1 4 8 .
Avian Leucosis & Marek's Disease
in Australia
by
D. A. DICKINSON (*).
INTRODUCTION
Until recent years the term « Avian Leucosis complex »
on simply « Leucosis » has been used in Australia, as in
other countries, to refer to the group of diseases affecting
poultry which, it is now universally accepted, comprise two
distinct groups of conditions differing both in aetiology and
clinical and pathological manifestation : the Leucosis/sarcoma
group and Marek's Disease.
The lymphoid/sarcoma group includes the pathological
entities Lymphoid Leucosis (syn. visceral lymphomatosis, big
liver disease) Erythroid Leucosis (syn. Erythroleucosis, Erythroblastosis, Fowl leucaemia), Myeloid Leucosis (syn. Myelocytomatosis, white tumours) and other tumours including
sarcoma, endothelioma, kidney tumour and osteopetrosis
(syn. Marble bone, Big Bone disease).
Marek's Disease, both acute a n d classical forms, is characterised by lymphoid lesions in peripheral nerves and other
organs and tissues. It includes the ocular form (syn. ocular
lymphomatosis, grey eye or pearly eye disease), neural form
(syn. Neural Lymphomatosis, Fowl Paralysis, Range Paralysis) and visceral form (syn. Visceral Lymphomatosis).
(*) D e p a r t m e n t of A g r i c u l t u r e , S y d n e y , N e w S o u t h W a l e s ,
Australia.
— 142 —
It is only recently that the two have been dealt with separately as far as occurrence and recording of incidence is
concerned. Even so, on a flock basis, the two groups are
differentiated arbitrarily according to age of bird affected :
Marek's Disease when less than 20 weeks old, leucosis when
not less than 16 weeks old generally.
Occurrence.
All forms of the Leucosis/sarcoma group and Marek's
Disease occur in Australia. They occur in all the Australian
States and have no particular geographical distribution (1).
Lymphoid Leucosis is the most common disease manifestation of the Leucosis/sarcoma group and is the only one of
economic significance, the others being comparatively rare.
Accordingly in this paper the term leucosis will refer almost
entirely to Lymphoid Leucosis.
Usually one form of Marek's Disease predominates in individual outbreaks but tumours of skin and musculature are
seen infrequently.
Leucosis and Marek's Disease have been quite
since 1930 and probably m u c h before (2).
common
Incidence has increased since then to a varying degree in
the various States until by the 1960's in all poultry raising
areas of Australia, Leucosis and Marek's Disease were accepted as a most important cause of loss in poultry and of particular concern as neither treatment nor specific control
measures are available. Probably most flocks are infected
with both groups.
Lymphoid Leucosis in turkeys has been recorded on four
farms in New South Wales.
Incidence.
Exact figures on overall incidence and mortality and morbidity rates for Lymphoid Leucosis and Marek's Disease in
Australia are not available and it is possible to obtain only
an indication from such figures as are available.
In New South Wales 15 percent of all poultry specimens
examined at veterinary research stations of the State Depart-
— 143 —
ment of Agriculture in the period 1966-1969, were affected
with Leucosis or Marek's Disease. The annual figure at Veterinary Research Institute in Victoria was 17 percent up to
1959 and since then the incidence has increased to an average of 23 percent in the last three years.
In a replacement pullet survey in New South Wales in
1968, Leucosis was by far the greatest cause of losses in
flocks of all sizes comprising over 80 percent of the total
losses.
States conduct random sample laying t e s t s whereby hatcheries submit a sample of eggs for hatching and rearing
by the State. Production is measured for the first year of
lay. In many cases the incidence of Marek's Disease and
Leucosis is less in the sample than on the farm of origin.
Incidence of Leucosis in eleven completed random sample
laying tests in Victoria has varied from 1 to 5 percent without
any evidence of a decline or increase. Incidence of Marek's
Disease is less than 1 percent.
In New South Wales tests 3 percent losses occurred from
Leucosis and less than 1 percent from Marek's Disease both
conditions accounting for 10 percent of all mortalities.
In similar tests in Queensland, 76 percent of the losses
occurring from day-old to 17 weeks were due to Marek's
Disease and 55 percent from 17 weeks to 66 weeks to Leucosis. The average mortality in the eleven entries due to
Marek's Disease was 10 percent r a n g i n g from 2 to 18 percent.
In random sample tests conducted in Western Australia,
incidence of Marek's Disease has been less than 7 percent
and Leucosis less than 10 percent over the past six years.
In a broiler mortality survey in New South Wales, 0.07 percent birds died from Marek's Disease in 9 flocks, the average age being 8.2 weeks. Marek's Disease accounted for
2 percent ol all mortalities.
On farms in Victoria less than 10 percent losses occur due
to Marek's Disease in broilers and 8-12 percent in pullet
replacement flocks. The incidence of Leucosis ranges between 2 to 15 percent with an average flock incidence of
about 5 percent.
— 144 —
In New South Wales the average loss from Marek's Disease
is 10-20 percent with u p to 50 percent on commercial farms
and 80 percent in some small backyard groups. Losses from
Leucosis are less than 5 percent.
The average loss from Marek's Disease a m o n g broiler
chickens in Queensland is about 5 percent, and amongst
pullet replacement flocks, losses up to 30 percent to point
of lay are reported commonly.
Age
incidence.
Most outbreaks of Marek's Disease begin at 10 weeks but
are encountered at 5-6 weeks and as early as 4-5 weeks Leucosis is not seen commonly in Victorian flocks under 30 weeks
of age.
There is evidence of highly virulent strains of Marek's
Disease affecting chickens to some extent in most States in
that outbreaks occur as early as 4-5 weeks and cause up to
50 percent mortality. This was first described as occurring
in Victoria in 1961. The most common type of tumour
encountered in these cases is visceral (3).
Economic
Loss.
In general terms Marek's Disease is regarded as a most
important cause of loss in pullet replacement flocks. It causes significant loss in broilers when reaching marketing age.
From the figures given above it can be stated that Marek's
Disease and Leucosis together cause about 10-20 percent loss
in pullet replacement flocks.
In 1965 it was estimated that Marek's Disease and Leucosis
together cost the poultry industry, which ranks fourth of
the animal industries, $ Aus. 2 million annually compared
to $ Aus. 12 million for all diseases.
In Queensland the two diseases are considered to cost the
poultry industry one million dollars per year.
Diagnosis.
Diagnosis is based on clinical symptoms and gross pathology. Marek's Disease and Lymphoid Leucosis are differentiated on epidemiology, particularly the age of birds affected.
— 145 —
This is found sufficient providing a reasonable sample of
affected cases is available for examination. W h e r e there is
doubt, histopathology is used. Serology is not used. In a
current survey in Victoria, histopathology of the bursa of
Fabricius is being used to differentiate Marek's Disease from
Lymphoid Leucosis.
Control.
Control measures are directed primarily at Marek's Disease,
including rearing in strict isolation and sanitation, with allin, all-out system of management for broilers and on replacement pullet rearing establishments.
Egg producers are advised to maintain replacements in
isolation on the farm after receipt from the rearer. Similar
precautions can be taken by producers who do their own
rearing. They are advised to have rearing and laying houses
not less than 100 feet apart.
Frequent removal and destruction of affected
recommended in pullet replacement flocks.
birds
is
In some cases, to alleviate the stress of moving started
pullets from deep litter to laying cages, pullets are being
reared in cages from 5 weeks of age. At times this procedure appears to reduce considerably the incidence of Marek's
Disease.
Unaccountably on occasions particularly heavy mortality
is experienced in birds reared in a completely new shed.
Genetic
Selection.
Commercial poultry enterprises have commenced identifying and selecting strains of birds resistant to Marek's
Disease using as highly virulent virus material as possible.
Blood and tumour preparations have been used.
Some of these programmes have been in progress up to
two years and results are promising but the work is hampered by lack of highly virulent isolates of the agent.
— 146 —
Research.
Industry funds have been granted to University of Queensland for work aimed at isolating Marek's Disease virus with
a view particularly to obtaining attenuated or naturally avirulent agents to produce a vaccine. This will be the first
large scale investigation into the disease in Australia.
Tissue culture and transmission studies are in progress
at other institutions and observations arc being made on
tumour occurrence in flocks of known history for Marek's
Disease and Leucosis.
Funds have been sought by University of New England
to study various factors which may interact with Marek's
Disease, particularly diet and management.
The Victorian Department of Agriculture has tested
23 strains of layingtype fowls for susceptibility to Marek's
Disease. These were selected from entrants to random sample laying tests. Although incidence up to 10 weeks old ranged from 5 to 33 percent in inoculated groups and 2 to 17 per
cent in groups in contact with them, the differences are
not statistically significant.
The Department is investigating procedures for
selection of resistant strains.
Future
genetic
Work.
The appearance of an acute form of Marek's Disease in
other countries which have poultry industries run on intensive systems and work which this has stimulated in overseas
research establishments has given rise to increased interest in
Australia in both Avian Leucosis and Marek's Disease.
The need is recognised to conduct research into the several
aspects of Marek's Disease particularly.
Basic research is required to isolate and characterise local
agents leading to selection of vaccine strains and to enable
challenge work to proceed more rapidly.
Known highly susceptible and highly resistant strains of
birds need to be identified.
— 147 —
Epizootiological studies are required to examine virus survival in the Australian climate. Susceptibility of Australian
strains of fowls, possible vectors and influence of Australian
management practices on the disease.
Modes of inheritance of resistance and selection techniques
require investigation.
*
SUMMARY
Avian Leucosis and Marek's Disease occur in all poultry
raising areas in Australia.
All forms of Marek's Disease are encountered with usually
one predominating in individual outbreaks. While all forms
of the Leucosis/sarcoma g r o u p occur, Lymphoid Leucosis is
the only one of economic significance, the others being
comparatively rare. The only record in birds other than
fowls, is that of Lymphoid Leucosis in turkeys on four farms
Probably most flocks are infected with both groups. On
a flock basis, the two groups are differentiated arbitrarily
according to age of birds affected : Marek's Disease when
less than 20 weeks old, Leucosis when not less than 16 weeks
old.
Marek's Disease is regarded as a most important cause of
loss in pullet replacement flocks. It causes significant loss
in broilers when reaching marketing age.
Marek's Disease and Lymphoid Leucosis together
about 10-20 percent loss in pullet replacement flocks.
cause
There is evidence of highly virulent strains of Marek's
Disease affecting chickens in that some outbreaks occur as
early as 4-5 weeks old and cause up to 50 percent mortality.
Exact figures are not available to judge economic importance but it was estimated in 1965 that Marek's Disease and
Avian Leucosis together caused annual loss in Australia of
$ Aus. 2 million due to disease.
— 148 —
Diagnosis of the two groups is based on symptoms and
gross pathology. Histopathology is used occasionally, usually
to support research or surveys. Agents of Marek's Disease
and Avian Leucosis have not been isolated in Australia.
Control measures are directed mainly at Marek's Disease
and include rearing in strict isolation and sanitation with
all-in, all-out system of management for broilers, and wherever possible, pullet replacements.
Commercial enterprises have commenced identifying and
selecting strains of birds resistant to Marek's Disease using
blood or tumour filtrate. Results are encouraging but work
is hampered by lack of highly virulent isolates of the agent.
Industry funds have been allocated for work aimed at isolating Marek's Disease virus with a view particularly to
obtaining attenuated or naturally avirulent agents to produce
a vaccine. This will be the first large scale investigation
into the disease in Australia.
Greatly increased interest on a national scale in Australia
has followed the advances made with Marek's Disease and
Avian Leucosis overseas. The need is recognised to conduct
research into selection of resistant strains of birds, characterisation of agents in Australia and epizootiological studies.
*
ACKNOWLEDGMENT
The assistance of Chief Veterinary Officers of the States and
workers at Universities of Queensland, New England and
Melbourne is gratefully acknowledged.
(II. E.). — « Diseases of Domestic Animals in
Australia Part 4 Protozoan and Virus Diseases ». Serv.
Pubis. Dept. IIIth Ausi. vet. Hyg., 1 9 6 6 8 . Second
Edition.
1. ALBISTON
2 . HUNGERFORD (T. G . ) . — Diseases Poult.,
and
ROBERTSON
1 9 6 2 , 1 4 0 . ANGUS
Ltd., Sydney.
3 . GORRIE (C. J . R.). — Vic.
Vet. Proc,
1963-1964, 2 8 .
B. — Comptes rendus des Séances
Liste des Participants
A. — PAYS
Afghanistan
Dr. M . A. KHAMOSII, Director General of Veterinary Services,
Ministry of Agriculture, Kabul.
Australie
Dr. K. S. MCINTOSIJ, Director of Veterinary Hygiene, Commonwealth Department of Health, Canberra, A . C . T .
Dr. H. R. PEISLEY, Assistant Director of Veterinary Hygiene,
Corqmonwealth Department of Health, Canberra, A . C . T .
Dr. L. N. THORNTON, Chief Veterinary Officer, Commonwealth Department of Primary Industry, Canberra, A . C . T .
Dr. D. F. STEWART, Associate Chief, Division of Animal
Health, Commonwealth Scientific and Industrial Research
Organisation, Private Bag No. 1, P.O., Glebe, N.S.W.
Dr. L. C. LLOYD, Principal Research Scientist, Animal
Health Research Laboratory, Commonwealth Scientific and
Industrial Research Organisation, Parkville, Victoria.
Dr. P. R. HaRVEY. Chief Veterinary Officer (Veterinary Services), Department of Agriculture, Stock and Fisheries, Konedobu, Papua and New Guinea.
Australie
Dr. A. L. CLAY, Director, Division of Animal Industry,
Department of Primary Industries, William Street, Brisbane,
Queensland. 4000.
— 150 —
Dr. M. R. GARDINER, Chief Veterinary Surgeon, Department
of Agriculture, Jarrah Road, South Perth, Western Australia.
Dr. G . K MELDRUM, Chief Veterinary Officer, Department
of Agriculture, Hobart, Tasmania. (President, Australian Veterinary Association.)
Dr. D. T. OXER, Consultant Veterinary Officer, Department
of Agriculture, Treasury Gardens, Melbourne, Victoria.
Dr. D. A. DICKINSON, Assistant Principal Veterinary Officer
(Exotic Diseases), Department of Agriculture, State Office
Block, Phillip Street, Sydney, N.S.W.
Dr. R. E. CHURCHWARD, Registrar, Australian Veterinary
Association, 72 Parramatta Road, Camperdown, N.S.W.
Chine (République
de)
Pr. Dr. Y. P . Liu, Department of Veterinary Medicine, College of Agriculture, National Taiwan University, Taipei,
Taiwan.
Corée
Mr. Won-Chul PARK, Secretary, Embassy of Korea, Canberra, A.C.T.
Dr. J o n g Hee LEE, Chief of Disease Control Section, Veterinary Division, Livestock Bureau, Ministry of Agriculture
and Forestry, Seoul.
Dr. Yun Hi LIM, Director, National Animal Quarantine Station, Republic of Korea, Pusan.
Fiji
Dr. Brian D. GEE, Senior Veterinary Officer,
of Agriculture, Suva, Fiji.
Department
Inde
Dr. Krishna RAO, Animal Husbandry Commissioner, Ministry of Food, Agriculture and Community Development,
Krishi Bhavan, New Delhi.
— 151 —
Indonesie
Dr. A. DAHLAN, Chief, Directorate
Salemba Raya 16, Djakarta.
of
Animal
Health,
Pr. Dr. R. Tandjung ADIWINATA, Director, Institute of Animal Virus Diseases, P.O. Box W o . 3, Surabaja.
Professor of Animal Sanitation, Parasite and Disease Control, Faculty of Animal Husbandry, Brawidjaja University,
Malang, Indonesia.
Iran
Dr. M . KAVEH, Directeur
Box 656, Téhéran.
Général, Institut
Razi, P .
0.
Japon
Dr. Kenzo NOBUTO, Director, Animal Health Division, Animal Industry Bureau, Ministry of Agriculture and Forestry,
1-2, Kasumigaseki, Chiyoda-ku, Tokyo.
Dr. Sadaharu AOKI, Chief, Sakura Branch, Chiba Serum
Institute, 103, Oja-machi, Sakura, Chiba.
Laos
Dr. Houane SIHAPANYA, Directeur des Services Vétérinaires,
Vientiane.
Malaysia
Dr. S. T h i u R A I s i N G H A M , Deputy Director of Veterinary Services, Ministry of Agriculture and Co-operatives, Kuala
Lumpur.
Nouvelle-Calédonie
Dr. P. MÉTRAL Chef du Service de l'Elevage et des Industries Animales, Noumea.
Nouvelle-Zélande
Dr. S. JAMIESON, Director of Animal Health, Department of
Agriculture, Wellington.
— 152 —
Thaïlande
Dr. Siri SUBHARNGKASEN, Deputy Director-General, Department of Livestock Development, Ministry of Agriculture,
Bangkok.
U.S.A.
Dr. E. E. SAULMON, Director, Animal Health Division, Agricultural Research Service, U . S. Department of Agriculture,
Washington, D.C.
Dr. Nels KONNERUP, Livestock and Animal Health Technical
Assistance Bureau, Agriculture and Fisheries, Agency for
International Development, Washington, D.C.
B. — ORGANISATIONS INTERNATIONALES
O.I.E.
Pr. A. RAFYI, Président de l'O.I.E., Doyen de la Faculté
Vétérinaire, Université de Téhéran, P.B. 3262, Téhéran, Iran.
Dr. R. VITTOZ, Directeur de l'O.I.E., Paris, France.
Dr. Yoshio TANAKA, Representative of the O.I.E. in Asia,
Vice-President, Livestock Industry Promotion Corporation,
13, 3-Ghome, Likura-cho, Azabu, Minato-ku, Tokyo, Japon.
F.A.O.
Dr. C. Perumal PILLAI, F.A.O. Regional Veterinarian,
F.A.O. Regional Office for Asia and Far East, Phra Atit Road,
Bangkok 2, Thailand.
Dr. Hans-Heinrich KLITZ, Animal Health Officer,
c/- UNDP, P.O. Box 1647, Taipei, Taiwan.
Commission
Dr.
W.
GRANGER,
B.V.
du, Pacifique
Sc.,
Dip.
Ag.
F.A.O.,
Sud
Ec,
Dip.
Pub.
Ad.,
M.R.C.V.S., South Pacific Commission, P.O. Box No. 9, Noumea (P.O. Box 20, Canberra, A.C.T. 2600).
— 153 —
Observateur
Dr.
States
nam,
bassy,
David H. SCHAER, Chief Animal Health Branch, United
Agency for International Development (USAID) VietOffice of Domestic Production, c / - United States EmSaigon, Vietnam.
a) Discours d'ouverture.
Opening addresses.
Discursos de apertura.
DISCOURS
D'OUVERTURE
PRONONCE
PAR SON E X C E L L E N C E SIR WILLIAM
REFSHAUGE
DIRECTEUR GENERAL DE LA SANTE
AU M I N I S T E R E DE LA SANTE DU COMMONWEALTH
Je suis très heureux d'être avec vous ce matin à l'inauguration de la 8 Conférence Régionale sur les Epizooties
en Asie, en Extrême-Orient et en Océanie.
e
En vous souhaitant la bienvenue à Canberra je vous transmets également les souhaits du Ministre de la Santé du Commonwealth et du Gouvernement Australien d'un plein succès
de vos délibérations au cours de cette semaine.
C'est un événement historique : Pour la première fois la
Conférence régionale tenue sous le parrainage c o m m u n de
l'O.I.E. et de la F.A.O. se tient en Australie.
Nous sommes honorés que noire Pays ait été choisi pour
la tenue de cette Conférence.
Les epizooties, l'étude des maladies infectieuses des animaux
sont un domaine dans lequel l'Australie a beaucoup à contribuer et beaucoup à apprendre.
En tant que Nation nous dépendons beaucoup de nos industries rurales et notre économie est encore basée largement
sur leur productivité.
A son lour cette productivité est étroitement solidaire de la
santé de notre grand et petit cheptel.
Il est vrai que nous sommes dans une phase de rapide
expansion industrielle stimulée au cours de la dernière
— 156 —
decennie par l'énorme développement de nos ressources
minérales, mais l'Australie demeure sur une grande échelle
u n producteur de matière première.
Ceci étant considéré et en tenant compte des besoins présents
et futurs d'une population croissante en davantage de nourriture, nos industries rurales demeurent l'une des clés de
notre développement national.
La raison pour l'Australie d'une dépendance continuelle
de ces industries rurales est évidente lorsque nous considérons
l'importance de notre cheptel.
Il existe presque 16 millions de bovins de boucherie en
Australie et la production totale de viande durant l'exercice
financier en cours est évaluée à 1.725.000 tonnes.
Nous possédons le plus grand cheptel ovin du monde : les
différentes races de moutons totalisent plus de 176.000.000 de
têtes et ce cheptel ovin fournit plus d'un quart de la laine
produite dans le monde et plus d'un tiers de cette laine
comprend la fine toison de la race mérinos.
La valeur globale de la production rurale en 1968/1969
a été évaluée à environ 4 milliards de dollars australiens.
La valeur d'exportation des produits ruraux
presque la moitié de ce montant.
représente
Il est évident que les bénéfices provenant d'une région qui
prend les dispositions nécessaires pour maintenir le contrôle
des épizooties profite à tous les Pays de cette région.
L'Australie est favorisée par l'absence relative de maladies
du bétail sur son territoire.
C'est la préoccupation constante du Service de Quarantaine
de l'Australie que les maladies animales exotiques pour le
continent australien ne pénètrent pas dans le pays en provenance des Pays d'outre-mer.
Au cours de son histoire, l'Australie, comme les autres
pays de cette Région de l'O.T.E., a été protégée de nombreuses
maladies du bétail par son éloignement des autres pays
d'élevage.
L'Australie ne pouvait être atteinte que par un long voyage
maritime dont la durée dépassait les périodes d'incubation
de la plupart des maladies animales.
— 157 —
Mais aujourd'hui les progrès obtenus dans les transports
ont créé de nouveaux problèmes pour les Autorités de Quarantaine dans le Monde entier.
Nous ne pouvons plus désormais compter sur notre isolement pour protéger notre bétail des ravages des maladies
exotiques. Le transport aérien, essentiel pour le commerce
mondial, a rapproché tous les Pays des Régions du Monde
où existent des maladies animales, souvent ignorées de leur
propre industrie de l'élevage.
De même, de nouvelles routes de transport maritime et
des bateaux plus rapides ont rendu possible le transport des
marchandises à un niveau sans précédent.
Ces transports maritimes sont aussi responsables en potentiel
d'un accroissement de la propagation des maladies animales
sur le plan international.
Les avions à réaction et les bateaux à conteneurs ont introduit une nouvelle dimension dans les voyages de passagers et
dans le commerce mondial, et en même temps apportent
de plus grands défis aux Services de quarantaine animale.
Le problème posé par ce risque croissant de transmission
des maladies animales est commun à tous les Pays.
Le niveau auquel chaque pays est menacé varie naturellement selon son état indemne relatif de maladies animales.
En Australie, par exemple, où nous sommes indemnes
de Fièvre aphteuse et de Fièvre catarrhale du mouton, nous
avons jugé nécessaire d'imposer de strictes mesures de quarantaine pour nous assurer qu'il n ' y a pas ou qu'il existe
un risque négligeable d'importer de telles maladies.
Chaque Pays doit établir ses propres règlements de quarantaine pour satisfaire ses propres besoins tout en permettant
le m a x i m u m de courant commercial sur les animaux et les
produits animaux compatible avec la sécurité.
Il est important que des liens étroits soient maintenus
entre les Pays et que des entretiens aient, lieu à de fréquents
intervalles sur les problèmes de maladies et sur les restrictions
dp quarantaine.
—
158
—
Nous devons développer la compréhension des raisons pour
lesquelles les Pays considèrent ces problèmes de manière
différente selon les circonstances particulières de leurs intérêts
nationaux.
Il est très agréable de constater que deux Organisations
Internationales telles que l'O.I.E. et la F.A.O. travaillent
ensemble d'une manière si effective à ces Conférences
régionales.
En ma qualité de dévoué partisan d'une autre Organisation
internationale, l'Organisation mondiale de la Santé, je réalise
les tâches énormes que nous affrontons non seulement dans
le domaine de la santé h u m a i n e , mais aussi dans celui de
la santé animale, un domaine qui intéresse les activités de
toutes les trois Organisations, celui de l'importance toujours
croissante des Zoonoses. Ces maladies transmissibles des animaux à l'homme sont devenues récemment l'objet d'une
attention considérable et c'est un domaine dans lequel
davantage de travaux de recherches doivent être effectués.
Je suis sûr que la coopération de toutes les Organisations
Internationales s'intéressant à la Santé apportera les résultats
les plus effectifs dans ce domaine.
En Australie les études sont continuellement poursuivies
dans beaucoup de domaines de la santé h u m a i n e : Les Centres
de Recherche de la Division de la Santé Animale de l'Organisation de Recherches scientifiques et industrielles du Commonwealth, les laboratoires vétérinaires du Département de
l'Agriculture de l'Etat, les Laboratoires de Sérum du Commonwealth et les Universités. Je sais que vous aurez la possibilité après cette Conférence de visiter quelques-unes de
ces institutions.
J'espère que vous trouverez cette visite à la fois intéressante
et agréable.
Dans tous les domaines d'intérêt commun à l'O.I.E., à la
F.A.O. et à l'O.M.S., je crois que grâce au développement
continuel des connaissances et des idées, grâce à l'échange d'informations sur la fréquence des maladies et les méthodes de
diagnostic, de prophylaxie et d'éradication, nous atteindrons
— 159 —
notre objectif : celui du maintien de la santé, de la productivité des animaux pour le bénéfice du genre h u m a i n .
C'est pourquoi c'est avec un grand plaisir que je déclare
ouverte celle 8 Conférence sur les Epizooties en Asie, en
Extrême-Orient et en Océanie.
e
ALLOCUTION
PRONONCEE PAR LE DOCTEUR K. S. MC INTOSH
DIRECTOR OF VETERINARY
HYGIENE
COMMONWEALTH DEPARTMENT OF H E A L T H
EN AUSTRALIE
LORS D E LA CEREMONIE
D'OUVERTURE
DE LA CONFERENCE
Excellences,
Distingués Invités et Estimés Collègues,
Tout d'abord, qu'il me soit permis d'adresser mes sincères
remerciements à vous, Messieurs les participants à cette
Conférence, pour m'avoir élu Président de celle-ci.
J'apprécie l'honneur que vous m'avez ainsi fait et, en
même temps, je réalise pleinement la responsabilité qui
incombe nécessairement au Président.
C'est la première fois q u ' u n e Conférence conjointement
organisée par l'O.I.E. et la F.A.O. se tient en Australie,
c'est pourquoi il s'agit d'un événement mémorable pour nous
tous et en même temps d'un hommage à l'Australie.
Permettez-moi, mes chers Collègues, de vous souhaiter
de tout cœur la bienvenue à Canberra et de formuler l'espoir
que vous emporterez d'Australie u n bon souvenir de notre
capitale et aussi de l'ensemble de votre visite dans ce pays.
Je voudrais saluer individuellement chaque participant
mais malheureusement le temps ne le permet pas. Cependant,
— 161 —
je dois adresser une très spéciale bienvenue au Professeur
RAFYI, Président de l'O.I.E., qui est venu d'Iran, au Docteur
VITTOZ, Directeur de l'O.I.E., qui est venu de Paris, au
Docteur C. P. PILLAI, Représentant régional de la F.A.O.,
qui est venu jusqu'à nous de Bangkok, et au Docteur TANAKA,
Représentant de l'O.I.E. dans cette Région, venu de Tokyo.
Nous sommes heureux d'avoir le plaisir de votre compagnie
et nous comptons sur l'aide et les conseils que vous avez
toujours apportés avec distinction en de semblables Réunions.
De la part de tous les participants, je voudrais également
exprimer notre reconnaissance aux Excellences et aux Hôtes
de marque qui nous honorent de leur présence à cette cérémonie d'ouverture.
Votre présence témoigne de l'importance que vous accordez
à cette Conférence et je suis certain qu'elle sera u n puissant
encouragement, si en vérité u n encouragement était nécessaire pour tous ceux d'entre nous, et tout spécialement ceux
qui ont franchi de longues distances pour se réunir ici.
Je pense que l'O.I.E. et la F.A.O. doivent être félicités
pour avoir agi de telle sorte en vue de poursuivre et de
stimuler les progrès de la lutte contre les maladies animales
dans la Région. Les deux Organisations ont une longue
tradition au service de la Santé du bétail dans le monde entier
et je suis certain que les représentants des pays réunis ici
maintiendront et développeront cette tradition.
Le domaine des épizooties, j ' e n ai la conviction, nous
offre une possibilité unique de coopération internationale.
Cette semaine, au cours de nos délibérations nous étudierons
des problèmes présentant un intérêt immédiat et à long terme
pour nous tous. C'est mon espoir le plus ardent que nous
allons non seulement procéder à un échange de connaissances mais aussi établir entre nous une plus grande compréhension des problèmes d'intérêt particulier et mutuel.
Les pays d'Asie, d'Extrême-Orient et d'Océanie ont établi
des relations de travail dans leur étude de l'évolution des
maladies épizootiques et des meilleures méthodes pour les
combattre.
C'est seulement en continuant à travailler ensemble sur
tous les sujets concernant les épizooties que nous pouvons
— 162 —
espérer atteindre l'idéal d'une Région indemne — ou relativement indemne — des maladies que nous aurons à étudier
au cours de cette Conférence.
A ce point de vue nous avons à apporter une importante
contribution.
Nous sommes tous très familiarisés avec les tâches que
nous avons à affronter dans cette Région. Je suis certain
que cette 8 Conférence marquera une importante étape sur
le chemin qui nous conduit vers nos objectifs.
e
ALLOCUTION
PRONONCEE PAR L E PROFESSEUR A. RAFYI
P R E S I D E N T DE L'O.I.E.
LORS DE LA CEREMONIE
D'OUVERTURE
DE LA CONFERENCE
Monsieur le Président,
Excellence,
Monsieur le Directeur de l'O.I.E.,
Monsieur le Représentant de la F.A.O.,
Mes chers Collègues,
Mesdames, Messieurs,
Permettez-moi tout d'abord de vous exprimer mes remerciements bien sincères pour l'intérêt que vous voulez tous
montrer en assistant à l'ouverture de cette Conférence et
aussi d'exprimer nos remerciements très vifs à tous ceux
qui ont apporté leur concours à la réalisation de cette
Réunion.
Cette Conférence, comme vous le savez déjà, a pour but
d'étudier les divers problèmes en rapport avec les maladies
contagieuses épizootiques des animaux.
Toutefois, vous savez aussi bien que moi que ces maladies
causent, non seulement des dégâts considérables à l'économie
de nos pays, mais que certaines d'entre elles comme la
— 164 —
Brucellose, la Leptospirose, pour ne parler que de deux
maladies qui figurent à l'Ordre du Jour de notre Conférence,
sont des Zoonoses, c'est-à-dire des maladies communes à
l'homme et aux animaux, qui menacent très sérieusement
la santé de l'homme.
Je n'ai pas l'intention de vous citer de chiffres, ni de vous
énumérer la liste de ces Zoonoses, je rappellerai seulement
en passant le désastre causé tout récemment par la Fièvre
aphteuse en Grande-Bretagne.
Les besoins de l'homme en protéine animale pour lui
assurer son bien-être sont une nécessité que nous ne pouvons
pas ignorer, malgré les promesses que nous ont faites les
hommes de science, les spécialistes en pétro-chimie de nous
procurer ces produits par la voie synthétique ayant recours,
par exemple, à des ferments ou autres, car je pense que
vous êtes aussi d'avis que le goût de l ' h o m m e d'aujourd'hui
n'adopterait pas si facilement une viande synthétique par
exemple.
C'est donc à nous, vétérinaires, de concerter nos
pour sauvegarder la santé de nos animaux.
efforts
A cette occasion, il n'est pas sans intérêt de rappeler encore
une fois la rapidité de contagion qui s'effectue de nos jours
grâce aux déplacements rapides et aux communications
faciles.
Il est d'une extrême urgence que les Gouvernements de
tous les pays encouragent et renforcent leurs Services Vétérinaires, afin de contrôler et d'endiguer les maladies contagieuses des animaux par des moyens efficaces, en empêchant
l'introduction d'une nouvelle maladie et en s'assurant de
ne pas laisser échapper une maladie contagieuse vers d'autres
pays.
En nous basant sur ce que je viens de dire, nous nous
rendons bien compte de l'importance de ce genre de Conférence que nous sommes heureux de voir se tenir aujourd'hui
à Canberra.
Il m'est un très agréable devoir de remercier le Gouvernement australien, son Excellence le Ministre de l'Hygiène,
ainsi que son Excellence Sir William REFSHAUGE, Secrétaire
Général du Ministère de l'Hygiène, nos Collègues vétérinaires,
— 165 —
en particulier le Docteur Mc INTOSH et, tous ceux qui ont
contribué à faciliter cette Conférence dans ce beau pays qu'est
l'Australie.
Monsieur le Président, je ne peux pas terminer cette
allocution sans vous dire l'estime dans laquelle nous tenons
tous votre pays et vous féliciter pour vos réalisations merveilleuses ; vous avez utilisé largement les techniques modernes
et vous avez résolu plusieurs questions vétérinaires grâce
à vos hommes de science et à vos Centres de recherche.
Votre contribution a été grande en assurant les protéines
animales, produits laitiers et viande à ce monde affamé
qui en a tant besoin, en utilisant au m a x i m u m des procédés
de réfrigération connus du monde entier. Toutefois, vous
n'avez pas négligé le côté industriel que vous avez si bien
développé dans votre pays.
En m'excusant d'avoir été u n peu long, je vous souhaite,
Monsieur le Président, mes chers Collègues, une réussite
éclatante pour vos travaux et votre compréhension internationale.
ALLOCUTION
PRONONCEE PAR L E DOCTEUR R. VITTOZ
DIRECTEUR DE L'O.I.E.
LORS D E LA CEREMONIE
D'OUVERTURE
DE LA CONFERENCE
Monsieur le Directeur Général de la Santé,
Messieurs les Délégués et Observateurs,
Qu'il me soit permis, ainsi que vient de le faire le distingué
Président de l'Office International des Epizooties, M. le Professeur RAFYI, d'adresser la profonde gratitude de l'O.I.E.
aux Autorités du Commonwealth de l'Australie, Pays-Hôte
de la Conférence, et tout particulièrement à Sir William
REFSHAUGE, Directeur Général de la Santé, représentant de
Son Excellence le Ministre de la Santé, ainsi que toutes les
autres personnalités des différents départements ministériels,
pour toutes les facilités accordées à la réalisation de cette
importante Conférence, à M. le Docteur Mc INTOSH, Directeur
de l'Hygiène Vétérinaire au Département de la Santé du
Commonwealth, et à ses dévoués collaborateurs, ainsi qu'aux
distingués rapporteurs de l'Organisation de la Recherche
Scientifique et Industrielle du Commonwealth et du Département de l'Agriculture des Etats du Commonwealth.
Nous sommes très heureux de constater que grâce aux
efforts faits solidairement par le distingué Délégué permanent
de l'Australie auprès de l'O.I.E., par le Docteur TANAKA,
— 16T —
Représentant de l'O.I.E. en Asie, par MM. les Délégués et
Directeurs des Services Vétérinaires de nombreux Pays
d'Asie, d'Extrême-Orient et de nombreux Pays de la région
du Pacifique représentés ici, efforts soutenus par la Direction
générale de la F.A.O. à Rome et son distingué Représentant
régional, le Docteur PILLAI, et par la Direction de l'O.I.E.
à Paris, notre Conférence régionale pour l'Asie s'est transportée pour la première fois sur le continent australien.
L'intérêt scientifique et technique de notre visite en
Australie est en effet considérable. Ce pays n'est-il pas avec
son voisin la Nouvelle-Zélande, l'un des plus grands éleveurs
mondiaux de moutons et de bovins ; l'industrie qui exporte
la laine, la viande et les produits laitiers n'a-t-elle pas atteint
dans ce pays un niveau très élevé de productivité et de
qualité ?
Or, le développement rationnel d'un tel cheptel, la protection sanitaire, médicale, ont été et demeurent assurés
par la compétence et la vigilance d'un Service Vétérinaire
remarquable, hautement organisé, disposant de cadres nombreux répartis judicieusement, de laboratoires de recherche,
de services de quarantaine très efficaces.
Ainsi, la profession vétérinaire internationale, très largement représentée dans cette Conférence, peut être légitimement
fière de l'oeuvre de longue haleine accomplie par nos collègues
australiens.
La réalisation de cette Conférence internationale en
Australie nous permet d'observer la progression géographique
continuelle des activités de notre Commission régionale pour
l'Asie au cours de ces Réunions itinérantes entreprises depuis
1952.
La Commission s'est en effet transportée successivement
au Pakistan : à Karachi en 1952 ; en Thaïlande : à Bangkok
en 1954 ; au Japon : à Tokyo en 1956 ; au Kazakhstan
(U.R.S.S.) : à Alma-Ata en 1958 ; aux Philippines : à Manille
en 1959 ; dans l'Inde : à la Nouvelle-Delhi en 1964 ; au
Japon : à Tokyo en 1967. et aujourd'hui en Australie à
Canberra, couvrant ainsi de nombreux secteurs épizootologiques en Asie méridionale, en Asie centrale, dans le SudIvsl, asiatique, dans la région du Pacifique.
— 168 —
Toutes ces actions itinérantes, poursuivies solidairement
avec nos collègues de la F.A.O., de l'O.M.S., de la Commission du Pacifique Sud et de nombreuses Organisations ont
pour effet d'établir des contacts indispensables entre les
Services Vétérinaires nationaux de nombreux pays du continent asiatique, de faire u n bilan assurément incomplet, mais
très large, de l'évolution des différentes maladies épizootiques
et des modes de lutte mis en œuvre contre elles.
Les nombreux rapports et documents présentés ou discutés
depuis plus de dix années, à l'occasion de ces Conférences
régionales en Asie, sont réunis et publiés dans le Bulletin
de l'O.I.E. et constituent les archives précieuses de cette
activité régionale à long terme.
Simultanément, un service d'information s'est continuellement développé grâce à la coopération de tous et permet
malgré certaines lacunes de recevoir et de diffuser à partir
de notre Bureau Central de Paris des documents qui sont
très précieux sur l'évolution des maladies épizootiques les
plus importantes.
Dans le domaine de la recherche appliquée, une coopération
agissante s'est développée entre les nombreux Laboratoires
Vétérinaires des pays d'Asie, d'Extrême-Orient, d'Océanie,
qui ont également la lourde tâche de l'établissement des
diagnostics, de la mise au point et de la production de
vaccins appropriés.
Les Directions des Services Vétérinaires des Pays-membres
ont pu faciliter la coordination scientifique des laboratoires
nationaux avec les spécialistes des Commissions hautement
spécialisées de l'O.I.E.
Ainsi, l'étude systématique des problèmes devant être
examinés sur les différents points inscrits à l'Ordre du Jour
de la présente Conférence se trouve, à priori, facilitée,
accélérée, parce qu'elle bénéficie de l'expérience déjà acquise
par les réunions antérieures des spécialistes.
Enfin, une telle Conférence, constituant une nouvelle
étape dans les activités de notre Commission régionale pourra,
sur la base des Conclusions antérieures, élaborer ses propres
— 169 —
Recommandations adaptées aux impératifs
zoo-sanitaire en grande évolution.
d'une
situation
Notre Conférence aura ainsi atteint une nouvelle fois
ses objectifs, dont l'essentiel est celui du renforcement,
dans l'intérêt général, de la coopération internationale dans
u n climat confiant et confraternel.
ALLOCUTION
D'OUVERTURE
DU DOCTEUR C. PERUMAL PILLAI
REPRESENTANT
DE LA
F.A.O.
Excellences,
Sir
WILLIAM,
Messieurs les Délégués,
Au nom du Directeur Général et du Directeur de la Production et de la Santé Animale de la F.A.O., le Professeur
JASIOROWSKI, j ' a i le grand plaisir de vous transmettre leurs
salutations et leurs meilleurs vœux de réussite à cette
Conférence Régionale sur les Epizooties en Asie, en ExtrêmeOrient et en Oceanie, organisée conjointement par l'O.I.E.
et la F.A.O.
Je voudrais également remercier le Gouvernement de
l'Australie pour avoir généreusement offert l'hospitalité à
cette Conférence et pour avoir pris des dispositions remarquables en vue d'en assurer le succès.
Les points inscrits à l'Ordre du Jour de cette Conférence
sont d'une importance vitale pour cette Région en raison
des efforts conjugués déployés par les gouvernements membres
en vue de résoudre les problèmes de la production et de
la santé animales, maintenant q u ' u n e percée technologique
a été réalisée dans la production céréalière. Les maladies
du bétail ont constitué u n obstacle majeur aux investissements privés dans la production animale, et tous les efforts
— 171 —
devront être faits en vue de contrôler efficacement et finalement d'éradiquer les principales maladies épizootiques de
manière à créer u n climat tel que les nations en voie de
développement de cette Région pourront non seulement combler leur déficit en protéines, mais aussi gagner et sauvegarder
leurs échanges internationaux.
C'est dans ce contexte que des Réunions comme celle-ci,
où nous nous réunissons périodiquement pour échanger nos
idées et nos expériences, sont d'une valeur inestimable et
ne peuvent aboutir qu'à des progrès en vue de la solution
des problèmes de la santé animale dans la Région.
Sir WILLIAM, votre présence parmi nous à cette cérémonie
d'ouverture prouve le grand intérêt que vous portez aux
problèmes de la santé animale, et nous sommes sûrs qu'elle
stimulera nos discussions.
Permettez-moi, Sir WILLIAM, de redire combien nous vous
sommes reconnaissants d'honorer de votre présence cette
cérémonie d'ouverture et de renouveler l'expression de notre
gratitude à toutes les personnalités australiennes qui ont
pris d'excellentes dispositions pour le succès de la Conférence.
Merci beaucoup.
ALLOCUTION
D'OUVERTURE
DU DOCTEUR YOSHIO TANAKA
R E P R E S E N T A N T DE L'O.I.E. EN ASIE
Votre Excellence,
Monsieur le Ministre,
Messieurs les Délégués et Observateurs,
C'est pour moi un grand honneur et un privilège de participer à cette Conférence en tant que Représentant de l'O.I.E.
en Asie et d'avoir été invité à parler au nom du Comité d'Asie.
Depuis notre première Réunion à Karachi, au Pakistan,
en 1952. c'est la huitième fois que nous nous réunissons ici
aujourd'hui. Comme vous vous en souvenez certainement, le
nombre des pays participants et celui des délégués n ' o n t cessé
d'augmenter à chaque Réunion, ce qui symbolise la portée
et l'importance de la présente Réunion. Non seulement notre
Réunion a été hautement appréciée par les diverses sphères
intéressées, mais encore on attend beaucoup de cette Réunion.
Cette Réunion a été rendue possible par le souhait et la
demande exprimés unanimement à la dernière Réunion,
tenue à Tokyo à l'automne de 1967, de la tenir en Australie
et l'acceptation de cette demande par le Gouvernement de
l'Australie, et par la décision de l'O.I.E. et de la F.A.O.
Je souhaite exprimer notre très vive gratitude et nos sentiments respectueux au Gouvernement de l'Australie, particulièrement à Son Excellence Monsieur le Ministre de la Santé,
à notre distingué collègue le Docteur MCINTOSIT et à ses colla-
— 173 —
borateurs, pour leur empressement à se comporter en hôtes
de la Conférence.
Je n'ai pas besoin de souligner ici que l'Asie est si vaste,
s'étendant de l'est à l'ouest, du nord au sud, contenant tant
de pays grands et petits, si divers par leurs conditions naturelles, sociales, politiques et économiques. De ce fait, nous
nous heurtons ici en Asie à toutes sortes de difficultés dans
la mise en oeuvre des campagnes contre les épizooties et
dans nos échanges de techniques et d'informations. Néanmoins, malgré ces handicaps, nous les peuples d'Asie avons
une destinée commune, un avenir grandiose et nous avons
d'immenses possibilités de développement futur et les nations
d'Asie représentées ici à cette Réunion font le m a x i m u m pour
atteindre cet objectif final pas après pas.
C'est une grande chance pour nous de tenir cette Réunion
ici en Australie, car l'Australie est u n des pays les plus
avancés du monde en matière d'industrie animale ; en particulier, elle a à son actif de nombreux et brillants résultats
dans le contrôle des maladies animales, dont elle peut être
légitimement fière, et au cours de cette Réunion nous aurons
la possibilité de visiter de nombreuses installations dont nous
pourrons beaucoup apprendre et dont nous pourrons rapporter
chez nous des éléments précieux pour améliorer notre propre
travail.
La mise en œuvre de la lutte contre les epizooties dont
nous sommes tous responsables peut ne pas avoir reçu le
crédit qu'elle mérite, dans la plupart des cas à l'ombre de
secteurs plus spectaculaires, mais personne ne peut nier
que nos services deviennent de plus en plus importants
parallèlement à l'expansion du commerce et du transport
international.
L'accumulation de nos découvertes scientifiques continuelles et nos efforts inlassables pour venir à bout des
épizooties ne contribueront pas seulement au développement
de l'industrie, animale mais auront un effet à longue portée
sur le développement économique de cette Région, et la
responsabilité de cette tâche repose sur nos épaules.
Permettez-moi de reprendre une phrase de mon allocution
à la dernière Réunion de Tokyo : « Rome n'a pas été bâtie
en un jour. » En gardant cela présent à l'esprit, travaillons
— 174 —
ensemble, la main dans la main, avec la fierté de faire notre
part pour rendre le monde u n peu meilleur et u n peu plus
heureux.
Le développement futur de la lutte contre les épizooties
ne peut être obtenu que par la conjugaison de nos efforts.
En ce sens, cette Réunion posera une pierre angulaire de
plus dans ces efforts conjugués tendant à la réalisation de
notre objectif final, l'éradication des épizooties.
En conclusion, permettez-moi de remercier à nouveau le
Gouvernement de l'Australie et Son Excellence, et de formuler
mes vœux de succès pour cette Conférence.
Je vous remercie.
Compte rendu des Séances
La Conférence Régionale 0.I.E.-F.A.O. sur les Epizooties
en Asie, en Extrême-Orient et en Océanie s'est tenue à
Canberra (Australie) du 20 au 28 octobre 1969.
Cette Conférence Régionale a été réalisée conformément au
projet de la Commission régionale de l'O.I.E. pour l'Asie
d'organiser conjointement avec la F.A.O. une Conférence
Régionale sur les Epizooties en Asie, en Extrême-Orient et
en Océanie, approuvé par le Comité de l'Office International
des Epizooties réuni à Paris en mai 1968 pour sa XXXVI Session Générale.
e
Il a été en même temps décidé d'accepter la généreuse
proposition du Gouvernement de l'Australie de bien vouloir
se comporter en Pays-Hôte de la Conférence.
Toutes les sessions plénières de la Conférence se sont tenues
dans la Salle Robert-Menzies, au Park Royal Motel, à
Canberra.
Cette importante Conférence a réuni les Délégations vétérinaires des Pays suivants : Afghanistan, Australie, Chine
(Taïwan), Corée, Iles Fidji, Inde, Indonésie, Iran, Japon,
Laos, Malaysia, Nouvelle-Calédonie, Nouvelle-Zélande, Thaïlande, U.S.A.
Ont également participé à la Conférence, en outre des
Représentants de l'O.I.E. et de la F . A , 0 . , organisateurs
conjoints, les Représentants de la Commission du Pacifique
Sud, de l'U.N.D.P., de l'U.S. Aid.
Le Bureau de la Conférence a été ainsi constitué : Président : Dr. K . S. MCINTOSH, Director of Veterinary Hygiene,
—
176
—
Commonwealth Department of Health, Australie ; VicePrésidents : Dr. A. DAHLAN, Chief, Directorate of Animal
Health, Indonésie, — et Dr. S. JAMIESON, Director of Animal
Health, Nouvelle-Zélande, — solidairement avec le Professeur
A. RAFYI, Président de l'O.I.E., le Docteur C. Perumal PILLAI,
Représentant Régional de la F.A.O. en Asie, le Docteur
R. VITTOZ, Directeur de l'O.I.E., le Docteur Y . TANAKA,
Représentant de l'O.I.E. en Asie.
La Conférence a été solennellement ouverte lundi matin
20 octobre 1969 par Sir William REFSHAUGE, Directeur Général
de la Santé, représentant Son Excellence Monsieur le Ministre
de la Santé du Commonwealth, en présence du Corps Diplomatique, d'éminents épidémiologistes du Corps médical et
de nombreuses personnalités. (Voir le texte des discours et
allocutions d'ouverture page 155.)
Ont été présentés au cours de la Conférence et, discutés :
— 4 Rapports sur le point 1 de l'Ordre du Jour : Fièvre
aphteuse — par les délégations de l'Inde, de l'Indonésie,
du Laos, de la Thaïlande ;
— 5 Rapports sur le point 2 de l'Ordre du Jour : Peste
bovine et Maladies ressemblant à la Peste bovine — par les
délégations de l'Afghanistan, de l'Inde, de l'Indonésie, de
l'Iran, de la Thaïlande ;
— 3 Rapports sur le point, 3 de l'Ordre du Jour : Péripneumonie
contagieuse
bovine (Epizootologie, Diagnostic,
Prophylaxie) — par les délégations de l'Australie, de l'Inde,
de la Thaïlande ;
— 5 Rapports sur le point 4 de l'Ordre du Jour : Brucellose
— par les délégations de l'Inde, de l'Indonésie, du Japon,
de la Nouvelle-Zélande, de la Thaïlande ;
— 6 Rapports sur le point 5 de l'Ordre du Jour : Leptospirose — par les délégations de l'Australie, de la Chine,
de l'Inde, du Japon, de la Nouvelle-Zélande, de la Thaïlande ;
— 4 Rapports sur le point 6 de l'Ordre du Jour : Maladies
transmises par les tiques — par les délégations de l'Australie,
de l'Inde, du Japon, de la Thaïlande ;
— 3 Rapports sur le point 7 de l'Ordre du Jour : Leucose
aviaire — par les délégations de l'Australie, du Japon, de
la Thaïlande.
— 177 —
D'autre part, des Notes sur plusieurs points à l'Ordre du
Jour avaient été préparées pour la Conférence par le Service
Vétérinaire du Viêt-Nam, ainsi q u ' u n e Note sur le Surra
présentée par la délégation de l'Indonésie.
Une importante documentation de base avait été mise
à la disposition de la Conférence par la Direction de l'O.I.E.
Cette documentation comportait notamment :
— les Recommandations de la Conférence régionale O.I.E.F.A.O. sur les Epizooties en Asie tenue à la Nouvelle-Delhi
en novembre 1964 ;
— celles de la Conférence régionale 0.I.E.-F.A.O. sur les
Epizooties en Asie tenue à Tokyo en octobre 1967 ;
— le Code Zoo-sanitaire International approuvé par le
Comité de l'O.I.E. en 1968 ;
— la Circulaire épizootique mensuelle N° 273 (Septembre
1969) de l'O.I.E. ;
— les Recommandations de la 3 Réunion du Groupe
d'Experts F.A.O./O.I.E./O.U.A. sur la Péripneumonie contagieuse des bovidés, tenue à Khartoum en 1967.
e
Epizootologie,
Diagnostic et Prophylaxie
de la Fièvre
aphteuse..
Le Docteur M. KAVEH, Directeur de l'Institut Razi à Hessarek (Iran) a bien voulu accepter de conduire la discussion
sur ce point consacré à la Fièvre aphteuse.
Tout d'abord, le Docteur KAVEH présenta son Rapport sur
la « Situation de la Fièvre aphteuse en Iran et dans les pays
voisins » (voir le texte de ce Rapport in Bull. Off. int. Epiz.,
1969, 71 [11-12], 1267-1270).
Ensuite, le Docteur C. Krishna RAO, Animal Husbandry
Commissioner du Gouvernement de l'Inde, à la NouvelleDelhi, présenta son Rapport intitulé : « Epizootiology, Diagnosis and Control of Foot-and-Mouth Disease in India » (voir
le texte de ce Rapport in Bull. Off. int. Epiz., 1969, 71 [11-12],
1271-1275).
Le Docteur Siri SUBHARNGKASEN, Deputy Director General,
Department of Livestock, Bangkok, présenta son Rapport :
« Foot-and-Mouth Disease in Thailand », reproduit in Bull.
Off. int. Epiz., 1969, 71 [11-12], 1277-1279.
— 178 —
La Réunion entendit ensuite le Rapport du Docteur Houane
SIHAPANYA, Directeur du Service Vétérinaire et de l'Elevage
du Laos à Vientiane, sur la « Fièvre aphteuse et les mesures
de prophylaxie au Laos ». Ce Rapport est reproduit in Bull.
Off. int. Epiz., 1969, 71 [11-12], 1281-1283.
Enfin, en l'absence d'une délégation du Viêt-Nam, une
Note préparée par le Docteur NGUYEN-VAN-TRINH, Directeur
de l'Institut National de Bactériologie à Saigon, intitulée
« An Epizootic of Foot-and-Mouth Disease in South Vietnam
— Current Status », fut communiquée à la Conférence.
Une discussion générale eut ensuite lieu, à laquelle participèrent les délégations de tous les pays intéressés ainsi que
les Représentants de la F.A.O. et de l'O.I.E.
Le Docteur PILLAI, Vétérinaire Régional de la F.A.O.,
précisa la position de son Organisation en ce qui concerne
l'infrastructure des Laboratoires spécialisés dans le diagnostic
et la production des vaccins contre la Fièvre aphteuse.
C'est ainsi que l'Institut Razi en Iran est un Laboratoire
régional pour les pays du Moyen-Orient.
D'autre part, le Laboratoire de Nong-Sarai en Thaïlande
effectue des typages du virus aphteux et produit du vaccin
anti-aphteux.
A une question posée par le Délégué de l'Afghanistan,
le Représentant de la F.A.O. exprima l'opinion que les problèmes posés par la lutte contre la Peste équine et ceux posés
par la lutte contre la Fièvre aphteuse sont différents, notamment en ce qui concerne la production des vaccins. En
matière de Fièvre aphteuse, la création de petits Laboratoires
dans chaque pays ne serait pas rentable.
Le Docteur KAVEH précisa que l'Iran avait accepté que
l'Institut Razi fonctionne comme Laboratoire de Référence
dans la Région. La capacité de production de l'Institut Razi
est de 12 millions de doses par an.
Le Docteur ADIWINATA, Directeur de l'Institut de Virologie
animale à Surabaya, relata les conditions dans lesquelles
les Services Vétérinaires d'Indonésie ont lutté contre la
maladie. L'éradication de la Fièvre aphteuse a été obtenue
dans son pays par la combinaison de l'abattage et de la
vaccination.
— 179 —
Le Docteur VITTOZ, Directeur de l'O.I.E., rappela les
Recommandations sur la Fièvre aphteuse faites par les
Conférences régionales tenues précédemment à la NouvelleDelhi en 1964 et à Tokyo en 1967.
L'organisation de la vaccination anti-aphteuse en Asie
méridionale et dans le Sud-Est asiatique soulève des problèmes
techniques et financiers très importants qui empêchent actuellement la réalisation de campagnes de vaccination sur u n e
grande échelle.
La création, l'installation et le fonctionnement d'un
Laboratoire de la Fièvre aphteuse exigent beaucoup de temps
et d'argent. Le nombre des spécialistes des techniques de
laboratoire en matière de Fièvre aphteuse est encore très
limité et la formation du personnel de laboratoire à tous
les échelons exige une longue préparation.
Cependant, il existe déjà en plusieurs pays d'Asie des
Laboratoires de la Fièvre aphteuse, très bien équipés et
pourvus d'un personnel hautement qualifié, qui peuvent
ainsi effectuer les typages de virus nécessaires pour les Services
Vétérinaires intéressés des pays de la Région et éventuellement mettre à la disposition des pays qui en feraient
la demande certaines quantités de vaccin spécifique sur la
base d'accords mutuels.
A la suite de ces différentes interventions, le Docteur
MCINTOSH, Président de la Conférence, remercia le Docteur
KAVEH pour sa remarquable conduite de la discussion sur
la Fièvre aphteuse et le pria de bien vouloir réunir u n groupe
de rédaction du projet de Recommandation sur ce point
de l'Ordre du Jour.
Epizootologie,
Diagnostic et Prophylaxie
et des maladies ressemblant à la Peste
de la Peste
bovine.
bovine
Sur la demande du Président de la Conférence, le Docteur
Krishna RAO, Animal Husbandry Commissioner du Gouvernement de l'Inde, accepta de conduire la discussion sur
ce point.
Les Rapports suivants furent
présentés successivement
:
— « Recent outbreak of Rinderpest, in Iran », présenté
par le Professeur A. RAFYI, Président de l'O.I.E.
— 180 —
Ce Rapport est reproduit in Bull.
71 [11-12], 1289-1291.
Off.
int.
Epiz.,
1969,
— « The Rinderpest situation in Afghanistan », présenté
par le Docteur M. A. KHAMOSH, Directeur Général du Service
Vétérinaire de l'Afghanistan.
Rapport reproduit in Bull. Off. int. Epiz., 1969, 71 [11-12],
1293-1295.
— « Rinderpest and Rinderpest-like diseases in India »,
présenté par le Docteur Krishna RAO, Animal Husbandry
Commissioner du Gouvernement de l'Inde.
1297-1301.
— « Rinderpest and Rinderpest-like diseases in Thailand »,
présenté par le Docteur Siri SÜBHARNGKASEN, Directeur Général
adjoint du Service Vétérinaire de la Thaïlande.
1303-1304 ;
et enfin, un Rapport « Rinderpest-like disease on the Island
of Rali », présenté au nom de la délégation indonésienne
par le Docteur ADIWTNATA. Directeur de l'Institut de Virologie
animale de Surabaya.
1305-1306.
Après la présentation
ouverte.
de ces rapports la discussion
fut
Le Professeur A. RAFYI, Président de l'O.I.E. attira l'attention de la Conférence sur l'intérêt présenté par le Document
d'actualité N° 5 sur la Peste bovine en Asie diffusé — en
langue française et en langue anglaise — en juin 1969 par
la Direction de l'O.I.E.
Le Docteur E. E. SAULMON (U.S.A.), Directeur de la Division
de la Santé Animale à Washington, évoqua la Campagne
conjointe contre la Peste bovine en Afrique, dont la troisième
phase vient de s'achever et qui a permis une amélioration
considérable de la situation en ce qui concerne la Peste
bovine sur le continent africain. Le succès de cette campagne
— 181 —
démontre l'opportunité d ' u n e coordination
la lutte contre cette maladie en Asie.
régionale
de
Ensuite, le Docteur Vittoz, Directeur de l'O.I.E., souligna
la nécessité d'une notification rapide à l'O.I.E. des nouveaux
foyers de Peste bovine partout où ils peuvent apparaître.
L'O.I.E. diffuse continuellement par ses Notes d'Information, ses Circulaires épizootiques mensuelles, éventuellement par des Documents d'actualité, u n nombre considérable de renseignements très utiles sur l'évolution des
epizooties, mais pour effectuer avec le m a x i m u m d'efficacité
désirable cette diffusion d'une importance vitale le Bureau
Central de l'O.I.E. dépend entièrement des informations qui
lui sont fournies par les pays atteints par la maladie.
L'observation de cas de maladies des muqueuses dans
plusieurs pays de la Région où la Peste bovine n'avait pas
été constatée depuis une longue période a pu, dans certains
cas, entraîner une confusion et retarder ainsi l'établissement
du diagnostic tandis que l'épizootie se propageait.
D'autre part, la difficulté du contrôle vétérinaire dans
des zones peu accessibles ou se trouvant dans des secteurs
d'insécurité peut compliquer énormément la tâche des
Services Vétérinaires sur le terrain.
C'est pourquoi la plus grande vigilance
s'impose.
Ensuite, plusieurs délégués portèrent intérêt aux conditions
dans lesquelles la Peste bovine s'est propagée aussi rapidement — au cours de l'été 1969 — en Afghanistan et,
en Iran. Les transports d'animaux de boucherie apparemment
sains par camions automobiles ont été à la base de cette
extension rapide de la maladie.
Fort, heureusement,
l'Institut Razi ont pu
campagne massive de
sur 10 à 11 millions
le Service Vétérinaire de l'Iran et
organiser rapidement et réaliser une
vaccination antipestique qui a porté
de têtes de bétail.
A une question posée par le Docteur Siri SUBHARNGKASEN
(Thaïlande) sur les conditions dans lesquelles le virus-vaccin
lyophilisé est transporté et utilisé dans l'Inde, le Docteur
Krishna RAO (Inde) fournit les explications nécessaires.
— 182 —
Le Docteur PILLAI, Vétérinaire Régional de la F.A.O., fit
observer que, faute d'une coopération effective des pays
d'Asie dans la lutte contre la Peste bovine, cette maladie
continuera à sévir dans la Région pendant de nombreuses
années. L'exemple fort démonstratif de la Campagne
conjointe contre la Peste bovine en Afrique devrait inciter
les pays d'Asie à coordonner eux aussi leur action de
manière méthodique.
II existe d'excellents vaccins antipestiques. C'est pourquoi
la mise en oeuvre de campagnes de vaccination selon u n
programme régional ou sub-régional serait parfaitement
réalisable à la condition que les pays apportent leur adhésion
à u n tel programme.
Sur la demande du Président, le Docteur Siri SUBHARNGKASEN
fit u n rapide historique de la campagne d'éradication conduite
en Thaïlande, qui fut réalisée en 4 ans et demi. Le vaccin
utilisé était celui découvert et mis au point par le Docteur
J. NAKAMURA du Japon. L'action sur le terrain a été menée
par 3 groupes comptant chacun 400 vétérinaires et agents
du Service Vétérinaire.
Le Docteur Krishna Rao à son tour décrivit les conditions
dans lesquelles a été entrepris et poursuivi depuis 1954 dans
son pays le Plan d'éradication de la Peste bovine. Jusqu'en
mars 1969, plus de 282 millions de bovins et de buffles
ont, été vaccinés, ce qui a entraîné u n e réduction très
importante du nombre de foyers de Peste bovine dans les
différents Etats. Pour consolider ces résultats, il est procédé
régulièrement à la vaccination des jeunes animaux. En même
temps, le cloisonnement sanitaire du pays est, effectué par
la création, à l'intérieur même du pays, de zones immunes
de part et d'autre des frontières inter-Etats.
Sur le désir exprimé par le Docteur ADIWINATA (Indonésie),
le Docteur VITTOZ lut et commenta les articles du Code
Zoo-sanitaire International de l'O.I.E. définissant les conditions dans lesquelles un pays peut être déclaré indemne de
Peste bovine.
La discussion fut ensuite portée sur le comportement
éventuel d'un bétail complètement réceptif dans le cas d'une
introduction accidentelle de la Peste bovine.
— 183 —
Le Docteur HARVEY, Chef du Service Vétérinaire en
Papouasie et Nouvelle-Guinée, a eu à ce sujet des entretiens
à Edinburgh avec le Docteur SCOTT. Celui-ci considère que
des animaux extrêmement réceptifs tels que les bovins
d'Australie ou de Nouvelle-Zélande manifesteraient u n e forme
aiguë de la Peste bovine.
Ensuite la discussion porta plus particulièrement sur les
maladies des muqueuses.
Le Docteur SAULMON (U.S.A.) déclara que l'on pense dans
son pays que la diarrhée infectieuse des bovins et les maladies
des muqueuses dont les symptômes cliniques sont différents
seraient causés par un même virus.
Le Docteur CLAY (Australie), Directeur de la Division des
Industries Animales au Queensland, rappela les préoccupations des Services Vétérinaires australiens lorsqu'ils se trouvèrent pour la première fois en présence d'une maladie
ressemblant à la Peste bovine.
Le Docteur VITTOZ rappela les travaux du Comité de l'O.I.E.
sur cet important problème. Lors de sa XXIX Session
Générale (mai 1961) et de sa XXXIV Session Générale
(mai 1966), le Comité de l'O.I.E. a entrepris une enquête
sur l'évolution et le diagnostic des maladies des muqueuses
des bovins, notamment : l'Entérite à virus, la Rhinotrachéite infectieuse, la grippe bovine à Myxovirus
parainfluenzae.
e
e
L'observation de ces affections, aussi bien dans le cheptel
bovin des Régions du monde indemnes de Peste bovine :
Amériques, Europe, Océanie, que dans celui des Régions
intertropicales de l'Asie et de l'Afrique où la Peste bovine
évolue avec une plus ou moins grande fréquence, entretient
un état de confusion dont les conséquences peuvent être
désastreuses dans le cas où un nouveau foyer de Peste bovine
no serait pas rapidement reconnu et signalé.
Cette situation implique la nécessité pour les Laboratoires
vétérinaires de tous les Pays intéressés d'être en mesure
d'établir — dans les circonstances parfois les plus inattendues — un diagnostic différentiel entre la Peste bovine
et ces maladies des muqueuses et, éventuellement, de faire
confirmer ou infirmer un diagnostic particulièrement délicat
— 184 —
et urgent par u n Laboratoire ayant une grande expérience
du diagnostic des différentes formes de la Peste bovine en
Asie ou en Afrique.
A ce point de la discussion furent examinées les conditions
dans lesquelles les pays de la Région pourraient effectuer
ou faire effectuer dans des Laboratoires spécialisés ces délicats
diagnostics différentiels.
Le Docteur K. NOBUTO, Directeur de la Division de la Santé
Animale au Japon, rappela que la création dans son pays
d ' u n Laboratoire de diagnostic et de recherches portant sur
les maladies virales est à l'étude.
Le Docteur KAVEH (Iran) suggéra qu'en raison de sa position
centrale en Asie méridionale et de l'expérience acquise en
la matière par ses Services Vétérinaires et Laboratoires, l'Inde
pourrait créer u n Laboratoire de référence pour la Peste bovine.
Cette suggestion recueillit également l'approbation de la
Conférence.
Il est, également bien évident que les Laboratoires hautement
spécialisés en matière de Peste bovine en différents pays
d'Asie méridionale et du Sud-Est asiatique sont en mesure
de développer — dans l'intérêt général — solidairement avec
les spécialistes du Japon et de l'Inde, des travaux de recherche
sur les différents aspects épizootologiques et immunologiques
de la Peste bovine et des maladies ressemblant à cette
maladie.
A la suite de ces intéressantes discussions, le Président
de la Conférence pria le Docteur Krishna RAO, avec la coopération du Docteur PILLAI et des délégués ayant participé
aux débats, de former u n groupe de rédaction de la Recommandation sur ce point de l'Ordre du Jour.
Péripneumonie
contagieuse
gnostic,
Prophylaxie).
des bovidés (Epizootologie,
Diag-
Le Docteur L. C. LLOYD (Australie), spécialiste des travaux
de recherche, notamment sur la Péripneumonie contagieuse
bovine, au C.S.I.R.O., à Parkville, Victoria, voulut bien
accepter de conduire les débats sur ce point important de
l'Ordre du Jour.
- 185 —
Furent, présentés :
— le Rapport « Contagious Bovine Pleuropneumonia in
India », par le Docteur C. Krishna RAO, reproduit in Bull.
Off. ini. Epiz., 1969, 71 [11-12], 1309-1313,
— et le Rapport : « Contagious Bovine Pleuropneumonia.
Aspects of eradication in Australia », par le Docteur
L. C. LLOYD, reproduit in Bull. Off. int. Epiz., 1969, 71
[11-12], 1329-1334).
La présentation de ce Rapport du Docteur LLOYD fut accompagnée de la projection d'intéressantes plaques diapositives
sur l'évolution et les lésions de la maladie.
Au cours de la discussion qui eut ensuite lieu, le Docteur
confirma que la Péripneumonie était devenue non seulement rare mais extrêmement rare en Australie.
CLAY
La maladie existe encore dans des propriétés situées dans
les zones de quarantaine du nord de l'Australie, respectivement
dans une partie du district de Kimberley Est de l'Etat d'Australie Occidentale et dans une zone du Golfe de Carpentaria
de l'Etat du Queensland.
Il rappela que l'acheminement du bétail sur pied sur de
longues distances avait joué, dans le passé, un rôle très
important dans la transmission et la diffusion de la maladie
en Australie.
C'est pourquoi, un des facteurs importants dans le succès
remarquable remporté par l'Australie dans la lutte contre
la Péripneumonie a été le développement du transport
motorisé — aisément, contrôlable — du bétail.
Cependant, la vaccination systématique a été le facteur
principal de l'élimination de la maladie.
Plusieurs orateurs des pays d'Asie désireux de développer
leurs Elevages nationaux au moyen de bétail importé éventuellement d'Australie demandèrent au Docteur LLOYD quelles
étaient les exigences devant être requises pour garantir
indemne de la maladie le bétail exporté.
Le Docteur LLOYD rappela que la réglementation australienne
relative à l'exportation exige :
-
186 —
— que les animaux aient présenté des résultats négatifs
à l'épreuve de fixation du complément effectuée à deux
reprises, à un intervalle d'au moins 21 jours et d'au plus
30 jours, la seconde épreuve devant ainsi être faite 14 jours
au plus avant l'embarqueemnt ;
— que les animaux aient été maintenus complètement
isolés de tous autres bovins ou buffles domestiques depuis
le jour de la première épreuve jusqu'à leur embarquement.
Il pense d'autre part que les pays importateurs auraient
tort de demander la vaccination du bétail australien importé
chez eux.
Le Docteur HARVEY signala que le territoire de la Papouasie
en Nouvelle-Guinée est probablement le plus grand importateur de bovins vivants d'Australie puisque depuis 7 ans
plus de 60.000 têtes de bétail australien, dont la plupart
en provenance du Queensland, y ont été importées.
La Péripneumonie n'a jamais été introduite à la faveur de ces
importations.
Les animaux ne sont pas mis en quarantaine à l'arrivée.
Les épreuves exigées sont, comme il a été déclaré précédemment, que deux épreuves de fixation du complément
aient été effectuées à 30 jours d'intervalle et que les animaux
ne proviennent pas d'une zone dite infectée.
A une question posée sur les méthodes de diagnostic
utilisées, le Docteur LLOYD déclara que la technique de l'immunofluorescence n'était pas employée pour le diagnostic
de la maladie en Australie puisqu'il existe déjà des méthodes
de diagnostic très satisfaisantes.
En ce qui concerne les restrictions imposées aux déplacements du bétail du nord au sud de l'Australie, celles-ci
répondent, surtout à la nécessité de prévenir la propagation
de la tique des bovins.
Dans u n avenir prochain, compte tenu de l'amélioration
considérable de la situation en ce qui concerne la Péripneumonie, la Commission nationale de lutte contre cette
maladie en Australie s'apprête à abandonner complètement
la notion du découpage du pays en régions ; la réglementation
de quarantaine ne s'appliquera plus qu'à des exploitations
individuelles.
— 18T —
A une question posée par le Docteur METRAL, Délégué
de la Nouvelle-Calédonie, le Docteur LLOYD déclara qu'il
était difficile de fournir des chiffres précis concernant le
nombre de vaccinations antipéripneumoniques effectuées.
1.250.000 doses de vaccin sont fabriquées annuellement par
le C.S.I.R.O. Ces doses sont utilisées surtout pour vacciner
les jeunes bovins dans les exploitations dont le nombre est
très élevé, mais la quantité de vaccin demandé diminue
continuellement.
La Commission nationale australienne considère que lorsque
des élevages n'ayant pas été vaccinés depuis 5 ans ne sont
plus atteints par la maladie, ceux-ci peuvent être considérés
comme indemnes.
A la suite de ces intéressantes discussions, le Docteur
MCINTOSH, Président de la Conférence, fit u n e synthèse
remarquable de la Réunion. Il pria ensuite les Docteurs
LLOYD, Krishna RAO et PEISLEY, de former u n groupe pour
élaborer un projet de Recommandation sur ce point de
l'Ordre du Jour.
Brucellose
(Epizootologie,
Diagnostic,
Prophylaxie).
Le Président pria le Docteur S . JAMIESON, Directeur de la
Nouvelle-Zélande, qui accepta, de bien vouloir conduire la
discussion sur la Brucellose.
Les Rapports suivants furent présentés :
— « Epizootiology, Diagnosis and Control of Brucellosis
in India », par le Docteur Krishna RAO ; Rapport reproduit
in Ball. Off. int. Epiz., 19T0, 73 (1-2), 3-7.
— « Brucellosis in Thailand », par le Docteur Siri
SUBHARNGKASEN ; Rapport reproduit in Bull. Off. int. Epiz..
1970, 73 (1-2), 9-15.
— « Present situation of Brucellosis in Japan », par les
Docteurs Kenzo NOBUTO et Koji SUTO ; Rapport reproduit in
Bull. Off. int. Epiz., 1970, 73 (1-2), 17-27.
— «Control of Bovine Brucellosis in New Zealand », par
le Docteur R. M . DAVIDSON ; Rapport reproduit in Bull. Off.
int. Epiz., 1970, 73 (1-2), 29-32.
— 188 —
Après la présentation de ces différents Rapports la discussion fut ouverte.
Le Docteur SAULMON (U.S.A.) rappela que, dans son pays,
le programme d'éradication de la Brucellose a été lancé
en 1 9 6 4 . Les progrès réalisés sont frappants. Actuellement,
la plupart des Etats sont déclarés indemnes de Brucellose
et 3 des Etats sur les 5 qui ne le sont pas encore pourront
être déclarés indemnes dans les prochains mois. En conséquence, alors que 6 . 9 0 0 cas de Brucellose h u m a i n e avaient
été reconnus en 1 9 4 7 , il n ' y a plus eu que 3 1 cas en 1 9 6 8 .
L'élimination totale de la Brucellose aux U.S.A. est prévue
pour 1 9 7 5 .
Le Docteur KAVEH signala qu'en Iran la Brucellose sévit
aussi bien sur les bovins et les caprins que sur les ovins.
Brucella melitensis est répandu dans tout le pays.
Actuellement, la vaccination est largement pratiquée, tant
sur les veaux que sur les vaches laitières.
La lutte contre la Brucellose ovine et caprine est basée
sur le dépistage par la séro-agglutination et sur la vaccination
systématique des adultes et des jeunes dans les troupeaux
contaminés.
Pour répondre à une question posée par un délégué,
le Docteur STEWART (Australie), avec l'accord du Docteur
JAMIESON, déclara que Brucella Ovis est rencontré en NouvelleZélande chez les béliers et les brebis ayant avorté. La prévention est basée sur l'isolement des béliers âgés d'une part
et des jeunes béliers d'autre part.
Répondant à une question du Docteur DAHLAN (Indonésie),
le Docteur STEWART déclara que le vaccin souche 4 5 - 2 0
utilisé en Australie est très semblable à celui utilisé au
Royaume-Uni et en Irlande.
Le Docteur THURAISINGHAM (Malaysia) attira l'attention sur
l'évolution de la Brucellose porcine, reconnue dans son pays
depuis 1 9 6 3 . La prophylaxie est basée notamment sur l'insémination artificielle des porcs. Au cours d'une enquête portant
sur un million de porcs abattus, la situation a été reconnue
très satisfaisante.
— 189 —
Il demanda ensuite s'il était nécessaire de faire vacciner
avec le vaccin S. 19 les vaches importées d'outre-mer.
Le Docteur STEWART répondit qu'il était préférable
porter des animaux indemnes non vaccinés.
d'im-
Cependant, le Docteur GARDINER considéra que la vaccination avec S . 19 effectuée depuis 15 ans a réduit sensiblement
la fréquence de la Brucellose en Australie occidentale.
Le Docteur CLAY (Australie) rappela que, 15 ou 20 ans
auparavant, la Brucellose porcine était fréquente en Australie.
Dans cette forme de la maladie, il n ' y a pas le plus souvent
avortement, mais plutôt stérilité complète chez la truie ou
mise-bas de porcelets malingres dont la plupart succombent
au cours des premières semaines.
Brucella suis étant plus contagieux pour l'homme que
Brucella bovis, il convient de prendre de grandes précautions
en effectuant les autopsies.
Le Docteur MELDRUM décrivit les conditions dans lesquelles
a été conduite la lutte contre la Brucellose en Tasmanie,
pays qui compte actuellement 775.000 têtes de bétail dont
un tiers est du bétail laitier.
Dans les zones où la fréquence de la maladie dépassait
10 p . 100, on vaccinait avec le vaccin S . 19 et on pratiquait
l'abattage sanitaire quand la fréquence ne dépassait pas
10 p. 100. Depuis 3 ans la situation est devenue extrêmement
satisfaisante.
Le Docteur METRAL signala que les bovins importés en
Nouvelle-Calédonie doivent n'avoir jamais présenté de symptômes de Brucellose et doivent avoir donné une réaction
négative aux épreuves sérologiques.
Le Docteur HARVEY fit remarquer que lorsque les vaches
sont atteintes de Brucellose au début de la gestation, elles
ne présentent pas souvent un titre positif aux examens
sérologiques pendant la gestation, et ceci jusqu'au vêlage
ou à l'avortement.
Ces résultats négatifs peuvent donner une sécurité illusoire.
C'est pourquoi il faut continuer à surveiller les vaches
jusqu'après leur vêlage.
— 190 —
Le Président fit ensuite un résumé des Rapports et de
l'intéressante discussion qui eut lieu. Il félicita les Rapporteurs
et les Délégués de leur excellente contribution aux débats.
Leptospirose
(Epizootologie,
Diagnostic,
Prophylaxie).
En ouvrant la séance, le Docteur MCINTOSH, Président de
la Conférence, pria le Docteur Y. P . Liu (République
de Chine - Taïwan) de bien vouloir conduire les débats sur
ce point de l'Ordre du Jour.
— « Epizootiology of Leptospirosis in India », par le Docteur
Krishna RAO.
73 (1-2), 35-38.
— « Leptospirosis
in
Off.
Thailand », par
int.
Epiz.,
1970,
le Docteur
Siri
SUBHARNGKASEN.
73 (1-2), 39-42.
Off.
int.
— « Studies on Leptospirosis in Taiwan
China »), par le Docteur Y . P. Liu.
73 (1-2), 43-48.
Off.
int.
Epiz.,
1970,
(Republic
Epiz.,
of
1970,
— « Rapid microscopic agglutination test for Leptospira
without non-specific reaction », par le Docteur E. RYU.
73 (1-2), 49-58.
Off.
int.
Epiz.,
1970,
— « Leptospirosis in Japan », par le Docteur Ryo YANAGAWA.
73 (1-2), 59-65.
Off.
int.
Epiz.,
1970,
— « A Review of the Leptospirosis of domestic animals
in Australia», par les fonctionnaires du Queensland Department of Primary Industries.
73 (1-2), 67-80.
Off.
int.
Epiz.,
— « Leptospirosis in New Zealand », par les
S.
JAMIESON, R
. M . DAVIDSON et
R.
M.
SALISBURY.
1970,
Docteurs
— 191 —
73 (1-2), 81-92.
Off. int. Epiz.,
1970,
— « Epidemiology, Diagnosis and Control of Leptospirosis
in Man », par le Professeur S. FAINE, Department of Microbiology, Monash University, Medical School, P r a h r a n , Australie.
73 (1-2), 93-99.
Off. int. Epiz.,
1970,
Après la présentation de ces Rapports qui mettent en
évidence l'importance considérable prise par la Leptospirose
dans les populations animales de l'Asie méridionale, du SudEst asiatique, de l'Extrême-Orient et de l'Australie, la discussion fut ouverte.
Le Docteur JAMIESON (Nouvelle-Zélande) souligna la gravité
des problèmes médico-vétérinaires posés par la Leptospirose.
Il exprima le souhait que, dans le cadre de la présente
Conférence, l'O.I.E. conjointement avec la F.A.O. établissent
une Recommandation insistant sur la nécessité d'une coopération entre les Services Vétérinaires et les Services Médicaux
des différents pays, tout particulièrement en ce qui concerne
les conséquences sanitaires de toute nouvelle méthode d'élevage et d'exploitation, notamment celle des vaches laitières.
Sur la demande du Président, le Professeur FAINE, d u
Département de Microbiologie de l'Ecole de Médecine de
l'Université Monash en Australie, qui revenait de Genève
où il avait participé à une Réunion d ' u n Comité d'Experts
de l'Organisation Mondiale de la Santé, fit u n rapport très
intéressant sur l'epidemiologie, le diagnostic et la lutte contre
la Leptospirose chez l ' h o m m e .
Le Président et les personnalités présentes à la Réunion
— à laquelle était venu se joindre Sir William REFSHAUGE,
Directeur Général de la Santé du Commonwealth Australien —
exprimèrent leur gratitude au Professeur FAINE pour son
exposé qui illustrait de manière aussi évidente les étroites
relations existant entre l'épidémiologie et l'épizootologie de
la Leptospirose.
Le Docteur KAVEH (Iran) demanda ensuite des informations
concernant les vaccins actuellement utilisés contre la Leptospirose.
—
192
—
Le Docteur CLAY signala que l'on utilise en Australie u n
vaccin préparé en Nouvelle-Zélande et u n autre préparé à
Sydney. Ces deux vaccins sont des vaccins inactivés.
Le Professeur RaFYI, Président de l'O.I.E., signala que
la Leptospirose a fait l'objet d'études importantes en Iran
depuis une douzaine d'années. Des épizooties ont évolué chez
les bovins et les ovins, causées par L. pomon et L. grippotyphosa identifiés par les examens sérologiques et les cultures.
Il attira l'attention sur la nécessité d'un diagnostic différentiel entre la Brucellose et la Leptospirose dans les foyers
nouvellement reconnus.
Le Docteur Siri SUBHARNGKASEN exprima le souhait que
l'exposé du Professeur FAINE soit diffusé à tous les pays
représentés à la Conférence. Le Directeur de l'O.I.E. lui en
donna l'assurance.
En ce qui concerne la prédominance de la maladie chez
l'homme et l'animal, le Docteur CLAY fit remarquer qu'au
Queensland la plus grande fréquence de la maladie chez
l'homme est constatée à proximité des abattoirs, abstraction
faite de toute cause géographique ou climatique.
Le Docteur MCINTOSH, Président de la Conférence, fit ensuite
une remarquable synthèse des Rapports et des discussions
qui eurent lieu.
Il pria les Docteurs Liu, JAMIESON et CLAY de se réunir
pour élaborer u n projet de Recommandation sur cet important
Point de l'Ordre du Jour.
Maladies transmises
Prophylaxie).
par les Tiques
(Epizootologie,
Diagnostic,
Le Docteur Siri SUBHARNGKASEN fut prié par le Président
de conduire la discussion sur ce Point.
— « Protozoan Diseases transmitted by Ticks in India »,
par le Docteur Krishna RAO.
Le texte de ce Rapport est reproduit in Bull. Off. int.
1970, 73 (1-2), 103-107.
Epiz.,
— 193 —
— « Diseases transmitted by Ticks in Thailand », par le
Docteur Siri SUBHARNGKASEN.
1970, 73 (1-2), 109-113.
Epiz.,
— « Ticks and Tick-Borne Diseases in Japan », par le Docteur Shigeo KITAOKA.
1970, 73 (1-2), 115-119.
Epiz.,
— « Tick-Borne Diseases of domestic animals in Australia»,
par les fonctionnaires du Queensland Department of Primary
Industries.
1970, 73 (1-2), 121-129.
Epiz.,
La discussion fut ensuite ouverte.
Le Docteur Liu signala l'existence de foyers de Piroplasmose à Taïwan. Les buffles d'eau et les bovins de race
locale sont résistants mais le bétail laitier d'importation est
sévèrement atteint.
Le Docteur PILLAI (F.A.O.) rappela l'enquête faite précédemment en Thaïlande sur les maladies transmises par les
tiques. Cette enquête a permis de constater le fort pourcentage
d'animaux atteints de Piroplasmose : u n tiers des buffles,
85 p . 100 des bovins entretenus en plein air. Le bétail laitier
entretenu en stabulation présente u n taux nettement moindre :
11,6 p . 100 d'infestation.
Il n ' a pas été possible, jusqu'à maintenant, de préparer
un vaccin contre l'Anaplasmose. D'autre part, il convient
de ne pas détruire totalement les tiques dont un petit nombre
s'avère utile pour maintenir u n certain degré de protection.
Le Professeur RAFYI rappela que l'Institut Razi avait effectué
d'importants travaux de recherche sur les maladies transmises
par les tiques en Iran. Ces travaux sont valables pour les
pays du Moyen-Orient.
L'Institut Razi a mis au point u n vaccin de culture tissulaire dont les résultats sont intéressants. Ce vaccin est utilisé
pour la prémunition du bétail infecté très réceptif.
— 194 —
Le Docteur THURAISINGHAM signala que la Babésiose, l'Anaplasmose et la Theilériose existent depuis longtemps en
Malaysia. Le bétail importé contracte des maladies graves
et de longue durée : 3 à 4 mois parfois, ce qui entraîne
des pertes économiques importantes, notamment avec les
vaches laitières. Les taureaux souffrent moins de la maladie
que les vaches gravides.
Le Centre de Recherches Vétérinaires du Queensland a bien
voulu fournir au Service Vétérinaire de Malaysia des vaccins
contenant à la fois Babesia argentina et Anaplasma
centrale.
Après
ces exposés sur les piroplasmoses, le Docteur
fit une brève communication sur u n e épizootie
de Surra causée par Trypanosoma
evansi ayant évolué en
Indonésie.
ADIWINATA
Le Président pria ensuite le Docteur Siri SUBHARNGKASEN
de bien vouloir réunir ses Collègues pour établir un projet
de Recommandation sur les maladies transmises par les
Tiques.
Leucose
aviaire (Epizootologie,
Diagnostic,
Prophylaxie).
Le Président pria le Docteur K . NOBUTO, Directeur du
Service Vétérinaire du Japon, de bien vouloir conduire les
débats.
— « Avian Leukosis in Thailand », par le Docteur
Siri
SUBHARNGKASEN.
1970, 73 (1-2), 131-132.
Epiz.,
— « Report on an epizootic of Marek's Disease in South
Vietnam », par le Docteur Vu DINH CHINH.
1970, 73 (1-2), 133-135.
Epiz.,
— « Avian Leukosis Complex in Japan », par le Docteur
Takehiko SHIMIZU.
1970, 73 (1-2), 137-140..
Epiz.,
— 195 —
— « Avian Leucosis and Marek's Disease », par le Docteur
A. DICKINSON (Australie).
1970, 73 (1-2), 141-148.
Epiz.,
Après la présentation de ces Raports, la discussion
ouverte.
fut
Le Président déclara que certaines communications montrent bien les problèmes que créent les programmes de
développement de l'aviculture mis en place dans certains pays
qui, actuellement, produisent, suffisamment de céréales pour
leur consommation interne et sont même sur le point de
devenir excédentaires, si bien qu'ils peuvent consacrer l'excédent de la production céréalière à l'élevage de volailles.
On peut se demander s'il faut investir beaucoup d'argent
dans la production avicole si, en raison de cette maladie,
elle est vouée à l'échec ?
Pour le Docteur Krishna RAO, la Leucose est décrite à juste
titre comme une maladie majeure pour l'industrie de l'aviculture. Le problème dans l'Inde n'est pas grave à l'heure
actuelle, soit dans les régions rurales, soit dans les stations
gouvernementales, mais certains établissements commerciaux
ont signalé une fréquence atteignant jusqu'à 15 ou 20 p . 100.
11 existe des exploitations très importantes où l'on met aussi
l'accent sur la fréquence de la Leucose.
L'industrie de la volaille en Inde fait des progrès et il
est certain qu'à l'avenir les problèmes se poseront de façon
plus sérieuse quand l'industrie aura atteint une plus grande
importance.
Il existe dans l'Inde u n certain nombre d'Instituts de
recherche qui travaillent tous sur les questions de l'aviculture.
Le Docteur ADIWINATA signale que la maladie de Marek
est reconnue en Indonésie depuis les années 1950. Cette
maladie n'a jamais constitué une menace dangereuse pour
l'aviculture indonésienne ; jusqu'ici, il n ' y a pas de déclaration obligatoire de cette maladie.
Il souhaiterait savoir, pour le cas où cette maladie serait
connue des pays d'où l'on importerait des poussins, quels
— 196 —
sont les règlements à mettre en vigueur pour permettre
à l'Indonésie de rester indemne de cette maladie nouvelle ?
Le Docteur KAVEH déclare que la Leucose en Iran se présente
plus ou moins comme dans les autres pays, c'est-à-dire
que la maladie n ' y était pas connue avant 1 9 5 0 mais s'y
est développée depuis que l'industrie de l'aviculture s'est
elle-même développée en Iran pour satisfaire les besoins
en viande.
Les seules mesures appliquées à l'heure actuelle contre
la maladie sont des mesures d'hygiène. Le fait d'acheter
dans des centres indemnes de Leucose serait déjà une aide
précieuse pour éviter la contamination de la maladie.
Le Docteur LEE n'est pas en mesure de fournir des détails
sur la Leucose en Corée. Cependant la lutte contre la Maladie
de Marek y est un grand problème pour les exploitations
avicoles recevant des poussins importés du Canada et des
Etats-Unis d'Amérique, soit du Japon.
Le Docteur THURAISINGHAM déclara que la Maladie de
Marek est très commune en Malaysia où elle est connue
et dépistée depuis de très nombreuses années. Les symptômes :
paralysie des extrémités, etc. sont caractéristiques et à
l'autopsie les principales lésions relevées sont celles qui
affectent le nerf sciatique et le foie. Les autres symptômes
sont semblables à ceux que l'on a déjà décrits. Cependant
cette maladie est observée également chez le canard et
souvent la mortalité est élevée quand les exploitations de
canards sont atteintes de la Maladie de Marek.
Il souhaiterait savoir si la Maladie de Marek ne pourrait
pas être transmise par des vaccins préparés sur embryon
de poulet.
Le Professeur RAFYI déclara qu'en ce qui concerne la
transmission des maladies par des vaccins avianisés, il peut
y avoir certains dangers à l'heure actuelle et il est recommandable d'écarter de tels vaccins.
A son avis, il faudrait renforcer cette notion que la transmission par le vaccin est toujours possible ou que le danger
existe, et il faut encourager les laboratoires à s'orienter
plutôt vers les vaccins de culture tissulaire qui sont souvent
plus actifs que le vaccin sur embryon de poulet.
— 197 —
Le Docteur NOBUTO exprima l'opinion qu'il peut arriver
que la transmission se réalise par le vaccin, et pourtant
il lui semble facile qu'avec l'embryon de poulet le virus
soit supprimé.
Le Docteur JAMIESON pense que la Leucose aviaire en
Nouvelle-Zélande ressemble à bien des égards à celle qui
a été décrite par le Docteur DICKINSON en Australie, et en
fait sa communication aurait pu se rapporter à la NouvelleZélande, ce qui est normal, puisque les deux pays échangent
des poulets.
La lymphomatose est le type le plus répandu de Leucose
aviaire en Nouvelle-Zélande.
L'aviculture est un secteur assez restreint qui répond aux
besoins internes. La Nouvelle-Zélande exporte néanmoins de
façon sporadique. Il ne connaît aucune solution satisfaisante
qui permette de garantir u n pays importateur contre tout
risque d'introduction de la Leucose.
Le Docteur SAULMON déclare que les différentes formes
de lympho-leucose constituent la maladie de la volaille la
plus déconcertante et la plus nuisible aux Etats-Unis ; elle
est largement distribuée dans le pays, mais il n'existe pas
de données statistiques sur l'incidence qu'elle peut avoir.
C'est la mise au point de vaccins qui offre les meilleures
perspectives dans ce domaine jusqu'à présent.
Le Docteur CLAY déclara ensuite que l'industrie de l'aviculture australienne exerce une certaine pression depuis
trente ans déjà et demande que l'on effectue davantage de
recherches sur cette maladie. Des expériences très importants sont faites dans d'autres pays, notamment aux EtatsUnis, mais les résultats ne sont pas encore tout à fait
satisfaisants, et il se félicite de la décision d'entreprendre
des recherches en Australie.
En ce qui concerne les mesures à prendre par les pays
importateurs contre l'introduction de la maladie, ils peuvent
demander aux pays fournisseurs d'assurer, dans toute la
mesure du possible, qu'au moins les œufs ou les poussins
d'un jour qu'ils exportent proviennent de volailles parmi
lesquelles il n'existe pas de signe clinique de la maladie
au moment de la collecte des œufs.
— 198 —
Après la présentation des Rapports et cette intéressante
discussion, le Président fit un résumé très complet des travaux
de la Réunion. Il proposa ensuite que les Docteurs NOBUTO
et DICKINSON se réunissent pour élaborer le projet de Recommandation sur ce Point de l'Ordre du Jour.
Les projets de Recommandations établis par les souscommissions composées des distingués Rapporteurs ont été
attentivement examinés et discutés par la Conférence au
cours de l'après-midi du jeudi 23 octobre. Le texte final
de ces Recommandations a été mis au point et adopté le
vendredi matin 24 octobre.
(Nota. — Le texte de ces Recommandations est reproduit
dans le présent numéro du Bulletin, p . 223 en langue française et p . 231 en langue anglaise.)
De brillantes réceptions ont été offertes à Canberra au
cours de la Conférence par Son Excellence le Directeur Général
de la Santé, par le Président de la Conférence, par les Représentants de l'O.I.E. et de la F.A.O.
En outre, u n voyage d'étude a été aimablement offert par
le Gouvernement australien aux Délégations qui ont pu se
rendre de Canberra à Melbourne et visiter notamment le
Sanctuaire Sir Colin MacKenzie de la Faune Sauvage, les
Laboratoires de Sérums du Commonwealth, la Division de
la Santé Animale du Laboratoire du C.S.I.R.O. à Parkville.
Enfin, u n certain nombre de visites individuelles ont été
organisées, notamment à la Quarantaine de Sydney.
Au m o m e n t de la séance de clôture de la Conférence,
le Président de l'O.I.E., le Représentant régional de la F.A.O.,
le Directeur de l'O.I.E., le Représentant de l'O.I.E. en Asie
et les Représentants des Délégations et Organisations ayant
participé à la Conférence ont adressé leurs félicitations et
l'expression de leur profonde gratitude aux Autorités du
Gouvernement australien, représentées par Sir William
REFSHAUGE, au Président de la Conférence, le Docteur
MCINTOSH et à ses dévoués Collaborateurs, pour l'excellente
organisation technique et matérielle de la Conférence et
pour la chaleureuse hospitalité de leur part accordée à
Canberra.
— 199 —
(Voir le texte des discours et allocutions de clôture de la
Conférence, p. 201 du présent numéro du Bulletin.)
Faisant suite aux remarquables Conférences régionales
organisées précédemment : à Karachi en 1952, à Bangkok
en 1954, à Tokyo en 1956, à Alma-Ata en 1958, à Manille
en 1959, à la Nouvelle-Delhi en 1964, à Tokyo en 1967,
cette Conférence de Canberra a été une nouvelle et importante
étape dans le développement d'une coopération internationale
confiante et efficace entre les Pays des différentes sub-régions
épizootologiques de l'Asie méridionale et centrale, du SudEst asiatique, de l'Extrême-Orient et de l'Océanie dans la
lutte contre les epizooties et la prévention de la propagation
de celles-ci.
Il convient également de souligner l'importance accordée
par cette Conférence comme les précédentes à la nécessité
d'une coopération très active entre les Services Vétérinaires
et les Services de la Santé publique dans la lutte contre les
anthropozoonoses.
En raison de la nécessité de l'établissement d'un bilan
zoo-sanitaire périodique et d'un renforcement continuel du
contrôle international des épizooties, il a été envisagé de
préparer et de tenir la neuvième Conférence régionale en Asie
en 1971 ou en 1972.
b) Discours de clôture.
Closing addresses.
Discursos de clotura.
ALLOCUTION
PRONONCEE PAR LE PROFESSEUR A. RAFYI,
PRESIDENT DE L'O.I.E.,
LORS DE LA CEREMONIE DE CLOTURE
DE LA CONFERENCE REGIONALE
SUR LES EPIZOOTIES
EN ASIE, EN EXTREME-ORIENT ET EN OCEANIE
CANBERRA (AUSTRALIE)
MONSIEUR LE PRÉSIDENT,
Permettez-moi de rappeler qu'après quelques jours de
travail très intéressants et aussi très bien réussis, nous sommes
arrivés à la fin de notre Conférence, et l'usage veut que
je dise quelques mots.
C'est donc avec grand plaisir et honneur que je vous
adresse ces quelques mots, non seulement au titre d ' u n e
obligation, mais, soyez en certains, très sincèrement pour
vous dire quelle admiration nous éprouvons tous à l'égard
de votre pays et de vous-même.
Je suis convaincu que mes collègues ici présents, venant
des différents pays, m'autoriseront à être non seulement
l'interprète des sentiments de l'Office international, mais
aussi des leurs, et, bien sûr, des miens, mais ceci n ' e m pêchera pas que je demande au Docteur VITTOZ, l ' h o m m e
le plus courageux et plein de dévouement, avec cet esprit
international apprécié de tous nos confrères dans le monde
entier, de venir aussi vous dire quelques mots.
Monsieur le Président, les quelques jours, hélas très courts,
que nous avons passés parmi vous el que vous avez comblés
par votre hospitalité dès notre arrivée, m'incitent à exprimer
— 202 —
nos vifs remerciemenls à votre Gouvernement, à M. le Directeur général, Son Excellence Sir William REFSHAUGE, à vous,
mon cher Président, à vos collègues, qui nous ont facilité
la marche si réussie et si brillante de notre Conférence.
Vous nous avez fait apprécier en si peu de temps le charme
de votre pays, vous nous avez fait entrevoir son avenir brillant.
Et puis l'arrangement si agréable et plein de succès de la
salle de conférence, les facilités diverses que vous nous avez
accordées, et que je n'arriverai pas à énumérer toutes,
grâce à votre savoir-faire, ont été des facteurs importants
et, si je peux dire, la garantie même du succès.
Je suis certain, après ce que nous avons
vous pouvez compter sur nous pour être, si
des ambassadeurs de votre pays auprès de nos
car nous parlerons avec beaucoup de sympathie
et de vos réussites.
constaté, que
je puis dire,
compatriotes,
de vos efforts
Permettez-moi, Monsieur le Président, de vous souhaiter,
à vous et à votre pays, une réussite de plus en plus éclatante
dans vos travaux, dans vos œuvres humanitaires.
En outre, il m'est aussi très agréable de dire que vous
avez été u n Président extrêmement averti, plein de bon
sens et d'intelligence, et que vous avez mené si bien nos
débats — faisant à la fin de chacune de nos séances un
excellent résumé de l'essentiel de nos discussions — que
tous mes collègues ici, j ' e n suis certain, se joindront à moi
pour vous présenter nos vifs remerciements et nos félicitations.
Je dois également, et de tout mon cœur, remercier vos
collègues australiens et tous ceux qui ont apporté leur
concours à la bonne marche de cette Conférence ; le secrétariat a fait un travail très utile, nos interprètes, avec une
patience digne d'éloges, nous ont beaucoup aidés ; qu'elles
acceptent nos remerciements.
Mes remerciements s'étendent également à tous ceux qui,
derrière ces m u r s ou ces rideaux, nous empêchant de les
voir de près, ont assuré, eux aussi, la réussite de notre
Conférence.
Je ne me pardonnerai pas si je ne disais pas aussi, de
votre part, mes chers Collègues, en même temps que de
— 203 —
la mienne, mes remerciements et nos félicitations au Docteur
VITTOZ dont vous connaissez l'énergie et qui nous assure
la réussite de toutes nos Conférences dans la Région.
Monsieur le Président, soyez certain que nous aurions
voulu prolonger notre séjour, mais, malheureusement, le
devoir et nos responsabilités nous appellent. C'est donc dans
l'espoir de nous revoir très prochainement que je vous prie,
Monsieur le Président, d'être l'interprète de nos sentiments
les meilleurs auprès de votre Gouvernement, et d'accepter
vous-même, une fois encore, nos remerciements bien
sincères.
A vous, mes chers Collègues, qui m'avez écouté si patiemment, je vous adresse également mes sincères remerciements
pour votre compréhension très confraternelle, votre collaboration régionale et internationale.
Je vous remercie.
(Applaudissements.)
ALLOCUTION
PRONONCEE PAR LE DOCTEUR C. PERUMAL PILLAI,
VETERINAIRE REGIONAL DE LA F.A.O.,
SUR LES EPIZOOTIESEN ASIE, EN EXTREME-ORIENT ET EN OCEANIE
MES CHERS COLLÈGUES,
Nous en sommes arrivés à la fin de cette semaine de travail
et je suis très heureux de voir assister à cette Conférence de
nombreux délégués. C'est la première fois que je participe
à une Conférence régionale de l'O.I.E. et de la F.A.O.,
tout ce qui a été discuté a donc été pour moi une première
expérience, mais les discussions que nous avons eues ont été
d'une si grande valeur pour l'Asie et l'Extrême-Orient que je
sentais combien j ' a u r a i s dû être plus au courant de ces Réunions avant de venir à celle-ci.
Les points qu'on a discutés couvrent un domaine dans
lequel la F.A.O. offre son concours depuis vingt ans dans
le but de renforcer l'activité régionale, et c'est dans le
domaine de l'amélioration de la situation zoo-sanitaire que
je travaille pour la F.A.O. dans la région.
Non seulement dans les domaines dont nous avons discuté,
mais dans d'autres domaines zoo-sanitaires, l'aide fournie
par la F.A.O. va être relevée à! tous les échelons.
Vos débats d'une si haute qualité, les recommandations
qui sont sorties de vos discussions ont un caractère très
— 205 —
pratique et vont donc aider la F.A.O. à prévoir une aide
qui sera efficace.
Or, la F.A.O. ne peut pas agir, comme vous le savez,
sans que les Gouvernements, les Pays-membres accordent
une priorité élevée aux questions de la santé animale. Il ne
serait pas possible, dans le cadre du système des NationsUnies de fonctionner autrement. Toute demande doit venir
par l'intermédiaire d'un Gouvernement vers le Bureau de
planification de la F.A.O., mais c'est une chose qui n'est
pas toujours comprise, notamment par des Directeurs de
Services vétérinaires de Gouvernements, qui quelquefois
blâment la F.A.O. ; j ' a i entendu exprimer ce point de vue
dans beaucoup de pays d'Asie, or, la procédure est une
chose qui compte et il faut la connaître, car ce n'est qu'en
se basant sur elle que la F.A.O. peut offrir son concours.
Il faut faire u n effort important pour débarrasser cette
Région de la Peste bovine. Je suis très reconnaissant au
délégué de l'Inde d'avoir accepté le fait que son pays doit
réaliser l'éradication de la Peste bovine, maladie qui règne
dans ce pays depuis toujours ; des efforts nationaux considérables ont visé l'éradication de la maladie, mais ne l'ont
pas complètement réalisée ; cependant, je suis assuré que
si l'Afrique avec son peuplement bovin nomade a pu réaliser
l'éradication de cette maladie, le continent d'Asie pourrait
le faire avant cinq ans.
Monsieur le Président, je vous remercie de la façon
admirable dont vous avez dirigé nos débats. C'est avec
plaisir que nous avons écouté le résumé que vous avez
si bien fait de chaque débat ; je serais étonné q u ' u n autre
délégué ait pu en faire autant et nous remercions également
tous les membres de votre personnel du travail accompli.
Je répète combien je suis heureux de voir Sir William
REFSHAUGE, spécialiste de la Médecine humaine, s'intéresser
à nos réunions, c'est une chose qui a beaucoup de valeur.
Je suis reconnaissant aussi à mes collègues de l'O.I.E.
de leur collaboration. Cette Conférence est surtout u n e
Réunion de l'O.I.E., la F.A.O. participe simplement à la
Réunion ; c'est la politique de notre Division de renforcer
les liens et la collaboration avec l'O.I.E. et vous pouvez
compter sur nous à l'avenir, Messieurs.
Je vous remercie.
(Applaudissements.)
ALLOCUTION
PRONONCEE PAR LE DOCTEUR Y. TANAKA,
REPRESENTANT DE L'O.I.E. EN ASIE,
SUR LES EPIZOOTIES
MESSIEURS LES DÉLÉGUÉS ET OBSERVATEURS,
Nous en arrivons aujourd'hui au terme de cette Conférence
fort réussie ; chacun d'entre nous ici présent, j ' e n suis
persuadé, sera d'accord pour penser que ces délibérations
qui portaient sur tant de problèmes auxquels nous faisons
tous face ont rendu notre Réunion extrêmement utile sur
le plan de la coopération internationale et du renforcement
de la coopération mutuelle.
Le Gouvernement australien a joué le plus grand rôle
dans cette entreprise, grâce à son concours qui appelle
la plus grande gratitude de notre part.
Au Président de l'O.I.E., le Professeur A. RAFYI, au Directeur de l'O.I.E., le Docteur R. VITTOZ, au représentant de la
F.A.O., le Docteur P. PILLAI, et aux représentants des Organisations internationales, j'aimerais présenter mes sincères
remerciements, car leurs conseils, nous ont été des plus
utiles.
Monsieur le Président, le Docteur MCINTOSH, et les deux
vice-Présidents, le Docteur S. JAMIESON, et le Docteur
O. DAHLAN doivent être remerciés de la façon dont ils ont
conduit nos débats.
— 20T —
Enfin, tous les délégués ont participé de façon dévouée
et très active à nos délibérations et doivent aussi de ce fait
être remerciés.
Comme vous le savez, Messieurs, le succès d'une Conférence
ou d'une Réunion dépend aussi toujours du travail de ceux
qui œuvrent en coulisse, mais de façon diligente et inlassable. A cet égard, je remercie sincèrement les membres
du Secrétariat et les interprètes ; je veux également remercier
le Gouvernement australien qui nous a permis de tenir
cette Réunion et d'améliorer notre connaissance de ce pays ;
pendant un court séjour, nous avons pu apprécier l'hospitalité
chaleureuse du peuple australien, ainsi que le vaste potentiel,
la vaste richesse de ce pays.
Je suis persuadé qu'à la suite de notre séjour ici, nous
réalisons tous que ce pays a beaucoup à apporter à la prospérité de chaque pays asiatique.
Pour terminer, je vous adresse tous mes vœux de réussite
et de succès pour votre pays, Monsieur le Président. (Applaudissements.)
ALLOCUTION
PRONONCEE PAR LE DOCTEUR R. VITTOZ,
DIRECTEUR DE L'O.I.E.,
SUR LES EPIZOOTIES
J'ai bien peu de choses à ajouter à ce qui vient d'être dit
par nos collègues, Monsieur le Président RAFYI, le Docteur
TANAKA et notre ami de la F.A.O., le Docteur PILLAI.
Cependant, je ne voudrais pas rester complètement muet
et ne pas vous dire tout ce que j ' a i au fond du cœur à la fin
d'une telle Conférence.
Il est certain que de telles Conférences ont une importance
énorme. Nous savons très bien que depuis 1952, il s'est créé
u n esprit tout à fait particulier dans cette Région de l'Asie,
de l'Extrême-Orient et de l'Océanie qui nous a permis,
effectivement, de réaliser des progrès considérables avec
des moyens parfois apparemment dérisoires, car le rôle de
l'Office, en réalité, est un rôle de stimulateur, de catalyseur.
Nous ne prétendons pas faire le travail, ce n'est pas notre
rôle ; nous avons pour effet de conseiller, de guider et
d'encourager.
A cet égard, je dois dire q u ' u n e telle Conférence a un
bilan positif considérable. Nous avons pu confronter les
points de vue, les situations de pays hautement producteurs
d'un bétail en élevage industriel intensif avec ceux de pays
dont l'élevage est un élevage extensif plus difficile à exploiter
— 209 —
et à développer, parce qu'il est fait dans des conditions
difficiles de climat et de nourriture. Il s'établit ainsi normalement des échanges entre des pays qui sont complémentaires.
Il est évident que l'Océanie, Région grande productrice
et exportatrice de produits animaux, est en m ê m e temps
un exemple en ce qu'elle a accompli par ses grands programmes de prophylaxie. Il est certain aussi que les pays
d'Asie et de l'Extrême-Orient ont besoin de ces relations
continuelles avec les pays du Pacifique.
Je me félicite tout spécialement de la participation très
amicale qui s'est manifestée à cette Conférence de la part
de nos collègues de la F.A.O. Je dois dire que nous sommes
des amis de la F,A,0, depuis toujours ; le rôle de l'Office
vis-à-vis de la F.A.O. est celui d'un organe consultatif,
la F.A.O. ayant le rôle considérable de l'application des
résolutions de l'Office, si elle le souhaite, et de la coopération
technique qui est un rôle complémentaire extrêmement agréable. Je suis très reconnaissant au Docteur PILLAI des mots
aimables qu'il a dits tout à l'heure, parce que nous sommes
tout à fait désireux, effectivement, de faciliter la tâche écrasante de la F.A.O. lorsqu'il est question d'aider les Paysmembres dans la réalisation de leurs programmes.
Enfin, je suis très heureux également de souligner ce
qui a été dit à propos de la coopération avec l'O.M.S. et
avec le corps médical. Une telle Conférence nous a permis,
précisément, de réaliser combien nous sommes solidaires,
combien il n'existe pas de frontières entre deux professions
et que l'épidémiologie et l'epizootologie forment u n tout.
A cet. égard également, nous avons beaucoup à apprendre
et grâce aux très bonnes dispositions prises, nous avons été
en mesure d'apprendre beaucoup de choses intéressantes en
ce qui concerne les zoonoses qui ont été traitées à la
Conférence.
Enfin, Monsieur le Président, je souhaiterais surtout
exprimer notre gratitude pour les conditions dans lesquelles
le Gouvernement australien, notamment sous le bienveillant
parrainage de Sir William REFSHAUGE, nous a reçus dans
ce pays ; nous sommes très sensibles à l'accueil qui nous
- 210 —
a été réservé, aux réceptions qui nous ont permis de connaître
avec plus d'intimité les personnalités australiennes dans leur
cadre habituel. Ceci pour nous a été d'un grand intérêt,
et je dois dire que nous y avons trouvé ce sentiment extrêmement chaleureux de l'amitié et de la coopération internationale auquel nous sommes tous tellement sensibles.
Merci, Monsieur le Président.
(Applaudissements.)
ALLOCUTION
PRONONCEE PAR LE DOCTEUR M. KAVEH,
DIRECTEUR GENERAL DE L'INSTITUT RAZI, EN IRAN
SUR LES EPIZOOTIES
MESSIEURS LES DÉLÉGUÉS,
MESSIEURS LES OBSERVATEURS,
A cette séance de clôture de la Conférence et au n o m
do la délégation iranienne, j ' a i grand plaisir à remercier
sincèrement tous ceux qui ont concouru à l'organisation de
la présente Conférence régionale sur les épizooties en Asie,
en Extrême-Orient et en Océanie.
Je remercie tout d'abord, et du fond du cœur, le Gouvernement australien qui a bien voulu être hôte de la Conférence,
et nos collègues australiens de l'hospitalité dont ils ont fait
montre à l'égard de toutes les délégations, hospitalité qui
a rendu si agréable notre séjour à Canberra.
Je remercie Monsieur le Directeur général de la Santé, Sir
William REFSHAUGE, qui a bien voulu ouvrir la Conférence;
tous les Vétérinaires que nous sommes doivent aussi remercier
les Services de Santé en Australie qui s'intéressent à l'Art
vétérinaire. Je puis les assurer que les Vétérinaires jouent un
grand rôle dans la Santé publique en luttant contre les zoonoses.
— 212 —
Mes remerciements vont également au Docteur MCINTOSH
qui a présidé la Conférence avec tant de compétence, a fait
preuve de patience en accueillant les idées, les suggestions
des différents délégués, et a fait preuve aussi de beaucoup
d'expérience en même temps que d'une grande connaissance
de toutes les questions examinées ; il a toujours trouvé les
meilleures formules pour présenter les recommandations
définitives et obtenir l'accord de toutes les délégations.
Je remercie M. le Professeur RAFYI, Président de l'O.I.E.,
le Docteur VITTOZ, Directeur de l'O.I.E., le Docteur PILLAI,
représentant de la F.A.O., le Docteur TANAKA, représentant
de l'O.I.E. en Asie, qui ont assisté la Conférence et ont
guidé nos délibérations.
Je voudrais aussi remercier le personnel du Secrétariat
qui a pris toutes les dispositions voulues pour nous fournir
les documents dont nous avions besoin.
Je remercie les interprètes, les traducteurs, les dactylographes, les personnes chargées des transports et des voyages
de leur concours et du travail dont ils nous ont fait
bénéficier.
Merci encore à tous.
(Applaudissements.)
ALLOCUTION
PRONONCEE PAR LE DOCTEUR KRISHNA RAO,
ANIMAL HUSBANDRY COMMISSIONER DANS L'INDE
LORS D K LA CEREMONIE DE CLOTURE
SUR LES EPIZOOTIES
EN ASIE, EX EXTREME-ORIENT ET EN OCEANIE
MONSIEUR
LE
PRÉSIDENT,
MESSIEURS LES DÉLÉGUÉS,
Il est fort triste d'arriver à la fin d'une Conférence après
quatre jours si heureux dans ce merveilleux pays, pourtant
notre départ approche.
Nous avons été très impressionnés par l'organisation qui
a été déployée depuis notre arrivée à Sydney où nous avons
été reçus par des personnes souriantes qui nous ont fait
passer sans aucune difficulté à travers les formalités de
douane et de santé. Nous avons été hébergés dans des hôtels
extrêmement confortables... et nous n'avons aucune envie
de quitter un pays aussi agréable.
Nous avons également été très favorablement impressionnés
par votre générosité, votre hospitalité. Nous pensions que
l'Australie était un pays dur, eh bien, il ne s'agit là que
d'une surface extérieure, l'intérieur au contraire est tendre !
Dans cette salle do Conférence, nous avons eu des débats
extrêmement animés, d'une tenue très élevée, et je me
félicite particulièrement que nos recommandations soient
de caractère pratique, je suis persuadé qu'elles pourront
être mises en œuvre.
— 214 —
Le Docteur MCINTOSH en particulier mérite d'être félicité.
Il a fait preuve d'énormément de patience ; nous ne pensions
pas qu'il était utile d'enregistrer les débats, car si chaque
délégué devait répéter ses interventions, il serait incapable
de le faire, alors que le Docteur MCINTOSH serait en mesure,
lui, de répéter tout ce qu'ont dit tous les délégués ! Outre
la faculté qu'il a de se souvenir de toutes les interventions,
sa conduite des débats a été tout à fait remarquable. Il a fait
preuve de beaucoup de tact, a maintenu la bonne h u m e u r
parmi tous et fait preuve, je le répète, de la plus grande
patience.
Nous avons tous été extrêmement frappés, non seulement
de la compétence avec laquelle il a conduit les débats,
mais de l'initiative dont il a fait preuve, de ses qualités
de chef, comme l'ont dit les orateurs précédents.
Vous avez tout u n état-major qui vous aide dans votre
tâche et toute votre organisation, traducteurs, chargés des
transports, personnel de secrétariat, etc., ont tous été extrêmement aimables à notre égard, nous ont fait sentir que
nous étions chez nous.
Nous avons réussi à faire ici des choses que nous ne pourrions pas obtenir dans notre propre pays et je voudrais
pour cela vous féliciter et vous remercier.
Sir William REFSHAUGE mérite aussi une mention toute
particulière. Nous sommes tout spécialement heureux, comme
scientifiques et vétérinaires, d'avoir eu la présence, je devrais
dire l'honneur de la présence de Sir William REFSHAUGE :
je suis très heureux qu'en ses mains compétentes la lutte
contre les maladies des animaux en Australie occupe la place
qu'elle mérite
Je suis persuadé que dans nos propres pays, nous travaillons
naturellement en collaboration avec les médecins, mais nous
tâcherons de réaliser le genre de collaboration qui existe
en Australie.
Le Docteur MCINTOSH s'est occupé, non seulement de notre
hébergement, de notre travail, grâce à u n programme très
chargé de 9 heures du matin à 5 heures de l'après-midi,
mais il a également veillé à nos loisirs. Nous avons été
très bien reçus à différentes réceptions. Hier, nous avons pu
— 215 —
visiter cette ville-jardin qu'est Canberra et nous avons été
frappés du développement qu'elle a pris ; cela nous a donné
une idée des perspectives offertes à l'Australie, de ce qu'est
en train de devenir l'Australie avec son potentiel énorme.
Je voudrais féliciter le Professeur RAFYI, Président de
l'O.I.E., le Docteur VITTOZ, Directeur de l'O.I.E., de l'excellent travail réalisé par cette Organisation. Il y a beaucoup de
différences entre les programmes d'élevage et de lutte contre
les animaux dans les divers pays et nous devons remercier
une Organisation telle que l'O.I.E. qui fait face à toutes sortes d'aléas financiers et autres dont on nous a parlé lors de la
dernière Session générale à Paris. Il est absolument nécessaire
que tous les pays représentés ici mettent à la disposition du
Docteur VITTOZ les moyens de fonctionner de façon plus
efficace.
Nous leur demandons une coopération rapide; nous nous
impatientons lorsque nous n'obtenons pas rapidement cette
coopération, mais il nous faut réaliser que nous devons, nous
aussi, leur apporter notre aide. En tout cas, le Professeur
RAFYI et le Docteur VITTOZ méritent d'être félicités de l'excellent travail qu'ils ont réalisé.
Je suis très heureux de la présence du Docteur PILLAI à
cette Réunion. Sa présence garantit que la F.A.O. tiendra
compte de toutes les recommandations formulées ici.
Je suis également très heureux de la présence du Docteur
TANAKA, Représentant régional de l'O.I.E. en Asie; sans sa
collaboration et, ses initiatives, je pense que nous n'aurions
pas été aussi bien représentés ici.
Pour terminer, je voudrais remercier à nouveau le Docteur
MCINTOSH, Sir William REFSHAUGE, le Gouvernement australien, ainsi que le peuple australien, et tous ceux qui ont
concouru par leur travail au succès éclatant de cette Conférence, Conférence qui a été d'une tenue si élevée que le
représentant de la Malaisie a une tâche difficile qui l'attend
pour la prochaine Conférence. Nous pouvons néanmoins
l'assurer de notre collaboration pleine et entière.
Merci Monsieur le Président.
(Applaudissements.)
ALLOCUTION
PRONONCEE PAR LE DOCTEUR SIRI SUBHARNGRASEN,
DEPUTY DIRECTOR GENERAL,
DEPARTMENT OF LIVESTOCK DEVELOPMENT
EN THAÏLANDE,
SUR LES EPIZOOTIES EN ASIE, EN EXTREME-ORIENT
ET EN OCEANIE
MESDAMES, MESSIEURS, MES CHERS COLLÈGUES,
Au nom du Gouvernement de la Thaïlande, je voudrais
m'associer aux remerciements des autres délégués et ajouter
quelques mots personnels.
Comme nous le savons tous, l'élevage serait impossible si
l'on ne luttait pas contre les maladies des animaux. La lutte
contre ces maladies, leur élimination éventuelle demandera
plusieurs années, mais avec les connaissances et l'expérience
acquises, ce but est réalisable. Or, ces connaissances, on
peut les obtenir en lisant des ouvrages scientifiques ou en
s'adressant à des Institutions; l'expérience s'acquiert. avec le
temps, mais l'échange d'opinions ne peut être réalisé que
dans des Conférences, qu'au sein de Conférences.
Autrement dit, les Conférences nous permettent une meilleure connaissance, une meilleure expérience, une expérience plus large qui permet à tous les Pays membres, participant à ces Conférences, de progresser de plus en plus
rapidement dans la lutte d'élimination des maladies des ani-
— 217 —
maux, non seulement sur le plan national, mais également
sur le plan régional.
C'est pourquoi je veux, Monsieur le Président, remercier
sincèrement à nouveau le Gouvernement australien qui a
bien voulu accueillir cette Conférence, qui nous a également
permis de voir votre merveilleux pays.
Je remercie sincèrement également Sir William REFSHAUGE,
Directeur de la Santé publique, qui nous a honorés de sa
présence et accueillis officiellement dès le début de cette
Conférence.
Ma gratitude va également aux Organisations Internationales, O.I.E. et F.A.O. qui ont rendu cette Conférence possible.
Je remercierai aussi le Docteur MCINTOSH, Président de la
Conférence, qui a conduit nos délibérations avec beaucoup
de compétence, le personnel administratif de la Conférence,
qui a pris toutes les dispositions nécessaires tant sur le plan
de l'hospitalité que sur les autres plans et qui nous ont permis
de nous sentir absolument chez nous ici; les interprètes, les
dactylographes aussi doivent être remerciées.
Monsieur le Président, avant d'en terminer, qu'il me soit
permis de souhaiter au Gouvernement australien et au peuple
d'Australie tout le succès possible dans toutes leurs entreprises.
Monsieur le Président, je vous demande de. transmettre
mes vœux et mes remerciements à votre Gouvernement
et
vous remercie.
(Applaudissements.)
ALLOCUTION
PRONONCEE PAR LE DOCTEUR E. E. SAULMON,
DIRECTOR, ANIMAL HEALTH DIVISION,
DEPARTMENT OF AGRICULTURE AUX U.S.A.,
DE LA CONFERENCE REGIONALE SUR LES EPIZOOTIES
Au nom de mon Gouvernement, je voudrais exprimer
notre satisfaction de l'invitation que nous avons reçue de
participer à cette Conférence qui s'est déroulée de façon si
agréable et si utile.
Il était facile de prévoir l'agrément que présenterait cette
Conférence, je crois, dès réception de l'invitation et n o m
n'avons pas été surpris de constater la bonne marche dans
laquelle cette Conférence s'est déroulée. Ce n'est nullement
par hasard, nous le savons tous, c'est grâce au dévouement
de vous-même, Monsieur le Président, et des membres de
votre personnel, de vos collègues, de vos collaborateurs.
J'exprime notre reconnaissance vis-à-vis de vous-même et
de votre Gouvernement; je ne veux pas parler de façon personnelle, mais nous sommes tous heureux de penser à la
collaboration future que nous aurons avec vous. (Applaudissements.)
ALLOCUTION
PRONONCEE PAR LE DOCTEUR K. S. MCINTOSH,
DIRECTOR OF VETERINARY HYGIENE,
COMMONWEALTH DEPARTMENT OF HEALTH
EN AUSTRALIE,
DE LA CONFERENCE REGIONALE SUR LES EPIZOOTIES
MES CHERS COLLÈGUES,
Je vous remercie tous de vos aimables paroles. Moi-même,
comme mes collègues australiens, sommes profondément
heureux, j ' e n suis sûr, des sentiments que vous avez exprimés ce matin; il est regrettable que les bonnes choses doivent
toujours avoir une fin... et nous sommes à la fin de cette
Réunion pleinement réussie, me semble-t-il.
Lorsqu'au début, l'Australie a été invitée à être hôte de
cette Réunion, c'est avec u n grand enthousiasme que je l'ai
proposé à mon Directeur général. Sir William REFSHAUGE et
à mon Ministre. Tous les deux m ' o n t vivement encouragé,
appuyé, et je leur exprime mes remerciements personnels
de cette aide.
Nous avons pu, au cours de cette Réunion, entendre des
présentations très intéressantes et utiles; la discussion qui les
a suivies a été d'une très haute qualité. De toutes les communications écrites et orales, nous avons des raisons d'être
fiers.
Je souligne que ce sont les participants qui sont responsables de la réussite de cette Conférence. Vous venez d'adopter
— 220 —
une série de recommandations très importantes, exprimées
sous une forme très claire, très succincte et qui reflète bien le
sens de nos débats.
Je remercie les animateurs des discussions et les sous-commissions qui ont si bien travaillé.
Le jour de l'ouverture, j'avais exprimé l'espoir non seulement que les échanges seraient fructueux sur le plan technique, mais que tous les assistants seraient amenés à mieux
comprendre les points de vue et les problèmes des autres
pays de leur région au cours de la Conférence. Ces espoirs
se sont vus pleinement réalisés.
Les réceptions étaient prévues en vue de permettre à des
relations d'amitié de s'instaurer; j ' a i vu se renouer maintes
amitiés existant depuis longtemps et je suis sur que de nouvelles amitiés ont été liées qui permettront que les bonnes
volontés et la coopération internationale fleurissent. Je voudrais bien que toutes les Réunions internationales se déroulent dans la même ambiance que la nôtre.
Je félicite encore une fois l'O.I.E. et la F.A.O. de s'être
mises ensemble pour promouvoir ces Conférences régionales;
ces deux Organisations, comme l'a dit le Docteur VITTOZ.
sont les agents catalyseurs sans lesquels celte synthèse des
connaissances et des idées n'aurait pas lieu.
Nos bons amis, le Professeur RAFYI et le Docteur TANAKA
de l'O.I.E., le Docteur PILLAI, de la F.A.O., sont satisfaits,
je suis heureux de les entendre le répéter, des résultats de
la Conférence.
Pendant l'absence de Paris du Docteur VITTOZ, je sais que
son personnel travaille énergiquemenl cl nous lui demandons
d'exprimer nos meilleurs souvenirs à Madame VITTOZ qui n'a
pas pu l'accompagner malheureusement en Australie.
J'espère que vous avez tous profité de nos travaux; je remercie le personnel que vous voyez au fond de la salle qui a si
bien travaillé en coulisse, car sans leur concours la Conférence n'aurait pas été possible.
— 221 —
Pour terminer, je vous remercie tous de votre bonne coopération, de votre patience avec moi et je félicite tous nos
collègues du succès de la Conférence.
Je vous souhaite une excursion agréable et utile après la
Conférence et je déclare maintenant formellement close cette
VIII Conférence Régionale de l'O.I.E. et de la F.A.O.
e
(Vifs
applaudissements.)
Recommandations
de la Conférence Régionale
O.I.E. - F . A . O .
sur les Epizooties en A s i e
en Extrême-Orient
et en
Océanie
Canberra (Australie)
20-28 octobre 1969
FIEVRE APHTEUSE
Considérant que :
— la Fièvre aphteuse est enzoo-épizootique et répandue dans
certains pays d'Asie et fréquente dans beaucoup d'autres
régions;
— certains pays dans cette région sont indemnes de la
maladie et par conséquent exposés à l'infection ou à une
réinfection à partir de pays où la maladie est fréquente soit
dans la Région, soit en d'autres Régions du monde;
— plusieurs types du virus sont responsables de la maladie
dans la région avec la possibilité de l'introduction de types
exotiques importés d'autres régions, et qu'il est nécessaire
de connaître leur répartition dans chaque pays et dans les
différentes parties de chaque pays, en vue d'établir des mesures de lutte efficaces;
— l'application de la méthode du « stamping-out », impliquant la destruction massive d'animaux infectés ou contaminés, est, pour diverses raisons, impossible dans des pays
où la Fièvre aphteuse est largement enzoo-épizootique et
qu'en de tels pays, l'utilisation de vaccins appropriés et d'un
— 224 —
prix de revient économique, conférant une immunité de
longue durée, associée avec l'application de mesures sanitaires rigoureuses, apparaît comme étant la méthode de
choix ;
La Conférence
recommande
que :
1. Tous les pays ou des parties de grands pays qui sont
demeurés indemnes de l'infection renforcent l'application
de rigoureuses méthodes de prophylaxie, y compris la quarantaine, afin de prévenir l'introduction de la maladie sur
leurs territoires ou sur les parties indemnes de leur territoire
2. Tous les pays infectés déploient tous les efforts nécessaires en vue d'établir u n diagnostic précis et le typage de
la souche ou des souches responsables dans les laboratoires
spécialisés existant dans la Région, tels que l'Institut de
Recherches Vétérinaires de l'Inde à Mukteswar, l'Institut
Razi à Hessarek en Iran, le Laboratoire de la Fièvre Aphteuse
de Nong-Saraï en Thaïlande, ainsi que le Laboratoire Mondial de Référence de la Fièvre Aphteuse de Pirbright (RoyaumeUni). Toutes les précautions doivent être prises pour les
expéditions de prélèvements suspects selon les instructions
données par Pirbright.
3. Les laboratoires cités ci-dessus, aussi bien que tous les
autres laboratoires spécialisés qui se consacrent au typage et
à l'étude des souches isolées dans la Région, échangent entre
eux des antisérums inactivés préparés à partir des souches
régionales en vue de comparer celles-ci et de produire des
vaccins à partir du ou des types les plus appropriés.
4. Les pays infectés dans la Région entreprennent ou étendent partout où il sera nécessaire les programmes de vaccination, en accordant la priorité à tout le cheptel de valeur
et à l'établissement de zones-tampons au long de leurs frontières, en utilisant seulement des vaccins inactivés préparés
au moyen des souches isolées de préférence dans les pays
intéressés ou au moins dans la Sous-Région.
5. Les animaux importés dans les pays infectés en vue de
l'élevage à partir de pays ou de zones de grands pays complètement isolées, indemnes de Fièvre aphteuse ou à partir
de pays infectés de types de virus différents de ceux existant
— 225 —
déjà dans les pays importateurs, soient vaccinés dans une
station de quarantaine de ces derniers pays au moyen de
vaccin inactivé préparé à partir de souches isolées, de préférence dans les pays importateurs intéressés ou au moins dans
la Sous-Région. Les animaux importés devraient être gardés
en quarantaine pendant une période m i n i m u m de trois
semaines.
6. Les pays, aussi bien ceux qui sont indemnes que ceux
qui sont infectés, profitent pleinement de la possibilité qui
leur est offerte d'utiliser les laboratoires de référence existant
déjà pour envoyer des chercheurs de leurs laboratoires en
stage de perfectionnement dans les techniques de diagnostic,
de typage et de production de vaccin contre la Fièvre aphteuse.
PESTE ROVINE ET MALADIES
RESSEMBLANT A LA PESTE BOVINE
Considérant avec une grande préoccupation la persistance
de la Peste bovine dans l'Inde et la réapparition de cette
maladie dans des pays de la Région demeurés indemnes de
la maladie depuis longtemps, en ce qui concerne les pays où
la maladie existe ou qui risquent l'introduction de la
maladie ;
La Conférence
recommande
que :
1. Tous les efforts soient faits en vue d'un diagnostic rapide
de la maladie, et qu'en attendant l'identification de la maladie, toutes les maladies ressemblant à la Peste bovine soient
l'objet des mêmes dispositions que celles mises en œuvre
contre la Peste bovine, et que la vaccination préventive soit
entreprise immédiatement jusqu'à ce que la confirmation du
laboratoire puisse être obtenue. Il est conseillé aux pays de
la Région de procurer les facilités nécessaires à l'établissement du diagnostic de la Peste bovine et des maladies ressemblant à la Peste bovine.
2. Les pays de la Région qui sont menacés par la Peste
bovine entretiennent des stocks suffisants de vaccin antiPeste bovine pour être en mesure d'entreprendre immédiatement les opérations de vaccination en cas d'irruption de la
maladie.
— 226 —
3. Etant donné la situation sérieuse résultant de l'aggravation de l'évolution de la Peste bovine en Afghanistan en
1969 et la menace en découlant pour les pays voisins, la
Conférence prie instamment la F.A.O. d'accorder toute l'aide
possible à l'Afghanistan en vue de l'élimination de la maladie.
4. Selon les recommandations faites par les deux précédentes Conférences Régionales O.I.E.-F.A.O. sur les Epizooties tenues successivement à la Nouvelle-Delhi en 1964 et à
Tokyo en 1967, et celles faites par la IV Conférence Régionale F.A.O. sur la Production et la Santé Animales tenue à
Ceylan en 1966, concernant la création d'un Laboratoire
Régional de Diagnostic et de Référence de la Peste Bovine,
la Conférence recommande que le Gouvernement de l'Inde
soit aussi invité à établir un tel laboratoire aussitôt que possible.
e
5. Considérant le grand succès du programme d'élimination de la Peste bovine accompli sur le Continent africain
grâce à l'octroi d'une aide bilatérale et internationale, la
Conférence recommande la mise en œuvre d'un programme
semblable en Asie pour libérer cette Région de la Peste
bovine.
6. En vue d'une élimination effective et rapide de la maladie dans cette Région, la Conférence recommande l'amélioration des systèmes intérieurs d'information et demande aux
pays de la Région de déclarer immédiatement à l'O.I.E., à
la F.A.O. et aux pays voisins les foyers de Peste bovine ou
de maladies ressemblant à la Peste bovine.
PERIPNEUMONIE CONTAGIEUSE DES BOVIDES
Ayant pris note de la situation fort satisfaisante existant
en Australie, où seulement deux exploitations connues, 1outes les deux situées sur la côte nord du Continent, demeurent
contaminées par la Péripneumonie contagieuse des bovidés
et que des mesures vigoureuses en vue d'éliminer celte maladie sont appliquées;
Ayant pris note que l'Etat d'Assam (Inde) a réussi à éliminer la maladie au moyen de la vaccination des bovins
dans la vallée du Brahmapoutre et que néanmoins on conti-
— 227 —
nue à contrôler cette Région afin de s'assurer
trace de la maladie ne persiste;
La Conférence
recommande
qu'aucune
que :
1. Dans les pays où la Péripneumonie contagieuse des
bovidés existe encore, tout effort soit fait pour l'éliminer au
moyen d'épreuves, de l'abattage et de la vaccination. Là où,
pour des raisons sociologiques, l'abattage n'est pas possible,
tous les bovins soient vaccinés avec un vaccin vivant efficace.
2. Toute épreuve pratiquée sur des bovins pour déterminer
l'existence de la Péripneumonie contagieuse des bovidés soit
effectuée au moyen de l'épreuve de fixation du complément
et q u ' u n e attention particulière soit accordée à la standardisation de cette épreuve en faisant des comparaisons avec celle
pratiquée dans d'autres laboratoires où des épreuves régulières sont effectuées.
3. Les laboratoires de la Région conservent leur personnel
formé dans la technique de l'épreuve de fixation du complément pour la Péripneumonie contagieuse des bovidés,
pour que des résultats exacts puissent être obtenus lorsque
sont soumis pour examen des sérums provenant d'animaux
suspects.
4. L'Australie soit priée d'entretenir des réactifs standard
pour le diagnostic de la Péripneumonie contagieuse des
bovidés comme un service rendu aux pays de cette Région.
5. Lorsqu'on importe des bovins des pays où la présence
de la maladie est certaine ou soupçonnée, des réglementations rigoureuses soient appliquées afin de s'assurer que la
maladie ne soit pas introduite. Que les pays important des
bovins vivants exigent que ceux-ci donnent des réactions
négatives à deux épreuves de fixation du complément pour
la Péripneumonie contagieuse des bovidés, les épreuves étant
effectuées à u n intervalle de 25 jours au moins et de 30 jours
au plus pendant que les animaux sont gardés en isolement
dans le pays exportateur et qu'ils proviennent d'une région
exempte de cette maladie.
6. Les pays de cette Région soient avertis du danger d'introduction de la maladie en Asie occidentale par du bétail
provenant des zones d'Afrique où cette maladie sévit.
— 228 —
7. Le principe du paiement d'une indemnité aux propriétaires dont le bétail a été saisi ou abattu à cause de la maladie
soit adopté.
8. Les recommandations de la 3e Réunion du Groupe
d'Experts F.A.O.-O.I.E.-O.U.A. sur la P.P.C.B., tenue à
Khartoum en 1967, soient prises en considération.
LEPTOSPIROSE
Reconnaissant l'importance croissante de la Leptospirose
chez les animaux domestiques et son incidence sur la Santé
Publique ;
La Conférence
recommande
que :
1. Les Pays-membres facilitent l'entreprise d'enquêtes en
vue de déterminer la fréquence et les aspects épidémiologiques
de la maladie.
2. En raison de l'incidence de la Leptospirose sur la santé
publique, les Pays-membres entreprennent, partout où cela
est possible, des programmes de recherches solidairement
avec les autorités compétentes de la santé publique.
3. Les Pays-membres tiennent compte du rôle des conditions d'exploitation des animaux dans l'extension de l'infection chez les animaux et aussi chez les personnes qui
s'occupent des animaux.
4. L'O.I.E. et la F.A.O. établissent une liaison étroite
avec l'O.M.S. en ce qui concerne celte Zoonose qui prend
de plus en plus d'importance.
MALADIES TRANSMISES PAR LES TIQUES
Considérant l'augmentation importante dans les Régions
de l'Asie et de l'Extrême-Orient du croisement des bovins
de races indigènes avec des bovins de type européen et
l'influence de ce croisement sur les maladies transmises
par les tiques :
La Conférence
recommande
:
1. Que les pays de la Région organisent des services
techniques capables d'effectuer l'immunisation des bovins
— 229 —
des races réceptives importées dès leur arrivée et avant
qu'ils ne soient exposés à l'infestation par les tiques. A ce
point de vue, l'Australie peut être priée d'apporter des
conseils et de fournir des souches de vaccin contre les
agents en cause.
2. Comme l'immunisation contre l'Anaplasmose n'est pas
pleinement satisfaisante, que des travaux de recherches soient
entrepris en vue d'apporter une amélioration effective à
l'efficacité de cette immunisation. A ce point de vue
l'Australie, qui a consacré u n temps et des ressources considérables dans ces différents domaines, peut être priée d'apporter son concours.
3. En ce qui concerne l'infestation par les tiques ellemême, que des programmes de vulgarisation soient appliqués
dans la Région en vue de faire connaître les pertes causées
par les tiques et les méthodes de lutte contre elles.
4. En ce qui concerne les difficultés rencontrées en
Thaïlande à propos de la Babésiose, sous des conditions qui
indiquent le rôle éventuel d ' u n vecteur autre que B. microplus,
que des recherches soient entreprises aussi rapidement que
possible pour déterminer si les mouches hématophages sont
capables de transmettre la maladie.
LEUCOSE AVIAIRE ET MALADIE DE MAREK
Etant donné que des statistiques précises pour déterminer
la fréquence et l'importance économique de la Leucose
aviaire et de la maladie de Marek, prises ensemble ou individuellement, n'ont pas été établies dans la Région, et que
la maladie de Marek tout particulièrement est considérée
comme étant une des causes principales de perte dans les
pays ayant une industrie avicole très développée, et que
cette maladie s'est manifestée chez des poussins importés
dans d'autres pays de la Région, où elle donne des
inquiétudes ;
Et reconnaissant qu'il n'existe ni traitement ni mesures
de prophylaxie spécifiques, bien que les résultats de recherches récentes soient prometteurs pour l'avenir en ce qui
concerne la maladie de Marek, notamment au moyen de.
— 2'30 —
la vaccination et de la sélection génétique de lignées de
poules qui seraient résistantes à la maladie ;
La Conférence
recommande
que :
1. Chaque pays établisse, de manière aussi précise que
possible, la fréquence dans son cheptel avicole des deux
maladies, la Leucose aviaire et la maladie de Marek, et
qu'il détermine l'importance économique de chacune d'entre
elles ;
2. Les recherches soient dirigées vers la mise au point
d'épreuves plus facilement utilisables que celles déjà existantes, afin d'établir avec davantage de précision u n diagnostic différentiel entre les deux maladies ;
3. Chaque pays exportant des poussins fournisse des facilités adéquates et les fonds nécessaires à l'entreprise et
à l'intensification de travaux de recherches essentielles sur
la maladie de Marek, notamment en vue de la mise au point
d'un vaccin économique et efficace et de la sélection génétique de lignées de poules résistantes à la maladie ;
4. En attendant, les poussins exportés devraient ne provenir que d'exploitations indemnes de Leucose aviaire et
de la maladie de Marek ;
5. Les producteurs de vaccin prennent des précautions
afin de s'assurer que les vaccins aviaires soient indemnes
de contamination par les virus de la Leucose aviaire et
de la maladie de Marek.
Recommendations
from the O . I . E . - F . A . O . Regional Conference
on Epizootics in Asia, the Far-East and O c e a n i a
Canberra (Australia)
20-28 October 1969
FOOT-AND-MOUTH DISEASE
Considering that :
— Foot-and-Mouth Disease in enzoo-epizootic and widespread in certain countries in the Asian region and prevalent
in many others ;
— some countries in this region are free from the disease
and are therefore open to infection or reinfection from
the countries where the disease is prevalent, whether in
this region or elsewhere ;
— several types of the virus are responsible for the disease
in the region with the possibility of introduction of exotic
ones from other areas and that it is necessary to know
their distribution in different countries and in different parts
of each country in order to formulate effective control
measures ;
— the stamping-out method, involving large scale desIruction of affected and in-contact animals, is for various
reasons not possible in countries where Foot-and-Mouth
Disease is highly enzo-epizootic and that in such countries
the use of suitable and cheaply produced vaccines, conferring
immunity of long duration, associated with the implementation of strict sanitary measures, appeal's to be the method
of choice ;
— 232 —
The Conference
recommends
that :
1. All countries or parts of the large countries which
have remained free from infection should enforce strict
prophylactic measures including quarantine to prevent its
introduction into their countries and free parts of the
countries.
2. Infected countries should make every effort to establish
an early diagnosis and typing of responsible strain(s) in
the specialised laboratories existing in the region, such
as the Indian Veterinary Research Institute, Mukteswar,
India ; the Razi Institute, Hessarek, Iran ; the F.M.D. Institute, Nong-Sarai, Thailand ; as well as the F.M.D. World
Reference Laboratory, Pirbright, United Kingdom. Every
precaution recommended by Pirbright for the shipment
of suspect samples should be adhered to.
3. The above laboratories, as well as any other specialised
laboratory engaged in the typing and study of strains
isolated in the region should exchange between themselves
inactivated antisera prepared from regional strains with a
view to comparing them and producing a vaccine from
the most suitable type(s).
4. Infected countries in the region should initiate or
expand wherever necessary vaccination programmes as a
first priority to cover all valuable breeding slock and to
establish buffer zones along their border, using only inactivated vaccine, prepared from strains isolated preferably in
the countries concerned or at least in the sub-region.
5. Animals imported into infected countries for breeding
purposes from countries or completely isolated areas of large
countries free from Foot-and-Mouth Disease or from countries
infected with types of virus different from those already
existing in the importing countries, should be vaccinated in
a quarantine station of the importing countries, with an
inactivated vaccine prepared from strains isolated preferably
in the importing countries concerned or at least in the subregion. The imported animals should be kept in quarantinein the importing countries for a m i n i m u m period of three
weeks.
— 233 —
6. Full advantage should be taken by countries both
free and infected to utilise the reference laboratories already
existing to send some of their laboratory research workers
for training in the techniques of diagnosis, typing and
vaccine production against Foot-and-Mouth Disease.
RINDERPEST AND RINDERPEST-LIKE DISEASES
Considering with great concern the continued incidence
of Rinderpest in India and the reappearance of this disease
in some countries of the region which remained free from
the disease for a considerable time, in respect of those countries where the disease exists or which are at risk of the introduction of Rinderpest ;
The Conference
recommends
that :
1. All efforts should be made for the immediate diagnosis
of the disease and pending the identification of the disease
all conditions simulating Rinderpest should be treated as
Rinderpest and prophylactic vaccination launched immediately
until such time as laboratory confirmation is obtained.
The countries of this region are advised to provide diagnostic
facilities for Rinderpest and Rinderpest-like diseases.
2. Countries of this region which are threatened with
Rinderpest should maintain adequate stocks of Rinderpest
vaccine to launch operations immediately when the disease
strikes.
3. In view of the serious situation arising out of exacervation of Rinderpest in Afghanistan in 1969, and the consequent threat posed to the neighbouring countries, this Conference urges F.A.O. to render all possible assistance to
Afghanistan to eradicate this disease.
4. Following the recommendations made at the last two
O.I.E.-F.A.O. Asian Regional Conferences on Epizootics held
in New-Delhi in 1964 and in Tokyo in 1967 and the recommendations made at the 4th F.A.O. Far-East Regional
Conference on Animal Production and Health held in Ceylon
in 1966 regarding the establishement of a Regional Diagnostic
and Reference Laboratory for Rinderpest, the Conference
recommends that the Indian Government be also invited
to establish the same in India as soon as possible.
— 234 —
5. In view of the great success of (he Rinderpest Eradication
programme achieved through regional co-operation on the
African continent and through various bilateral and international assistance this Conference recommends a similar
approach in the Asiatic Region to free this area from
Rinderpest.
6. For the effective and early eradication of Rinderpest
from this region the Conference recommends the improvement of internal reporting system and urges on the
countries of this region for the immediate notification of
outbreaks of Rinderpest or Rinderpest-like diseases to O.I.E.,
F.A.O. and to the neighbouring countries.
CONTAGIOUS BOVINE
PLEUROPNEUMONIA
Having noted the highly satisfactory situation in Australia
where only two known properties, both on the northern
coast, of the continent, remain infected with Contagious
Bovine Pleuropneumonia and that vigorous measures to
eradicate the disease are being applied ;
Having noted that the State of Assam (India) has successfully eradicated the disease by vaccination of cattle in the
Brahmaputra Valley but that this area is still being checked
to ensure that no disease remains ;
The
Conference
recommends
that :
1. In those countries where Contagious Bovine Pleuropneumonia is present every effort should be made to eradicate
it by testing, slaughter and vaccination. Where, for sociological reasons, slaughter, is not possible then all cattle
should be vaccinated with an efficacious live vaccine.
2. All testing of cattle for Contagious Bovine Pleuropneumonia should be carried out by the complement fixation
test and particular attention should be paid to standardization of the test by comparison with those in other
laboratories where regular testing is carried out.
3. Laboratories in the Region should retain personnel who
have been trained in the technique of the complement fixation
lest for Contagious Bovine Pleuropneumonia so that accurate
— 235 —
results can be obtained when sera from suspicious animals
are submitted.
4. Australia be urged to maintain standardised reagents
for the diagnosis of Contagious Bovine Pleuropneumonia
as a service for this region.
5. W h e n cattle are being imported from countries where
the disease is known or suspected, strict regulations should
be applied to ensure that the disease is not introduced.
Countries importing live cattle should request that they be
negative to two complement fixation tests for Contagious
Bovine Pleuropneumonia not less than 25 nor more than
30 days apart whilst held in isolation in the exporting
country and that they be from an area that is free of the
disease.
6. Countries in this Region should be aware of the danger
of the disease being introduced to West Asia by cattle
from the infected areas of Africa.
T. The principle of the payment of compensation to
owners whose cattle have been seized or slaughtered because
of the disease should be adopted.
8. The recommendations of the 3rd Meeting of the F.A.O./
O.I.E./O.A.U. Expert Panel on C.B.P.P. held in Khartoum
in 1967 should be noted.
LEPTOSPIROSIS
Recognizing the emerging importance of Leptospirosis
in domestic animals and the public health implication of
Leptospirosis ;
The Conference
recommends
that :
1. Member-countries should encourage the development
of surveillance programmes to determine the incidence and
epidemiological features of the disease.
2. Because of the public health implications of Leptospirosis Member-countries should, wherever possible, initiate
investigational programmes jointly with appropriate public
health authorities.
— 236 —
3. Member-countries should note the effect of animal
management in the spread of infection in animals, and
also to humans attending the animals.
4. O.I.E. and F.A.O. establish a close liaison with W.H.O.
on this increasing zoonosis.
TICK BORNE DISEASES
Considering the steady increase in the Asia/Far-East Region
of crossing of indigenous breeds of cattle with imported
European type cattle and the lick borne disease implications
thereof ;
The Conference
recommends
that :
1. Countries in the Region develop technical services
capable of carrying out the immunising of imported susceptible cattle immediately on arrival and before being exposed
to tick infestation.
In this regard Australia might be
asked to assist in an advisory capacity and as a supplier
of vaccine strains of the organisms concerned.
2. As immunization against Anaplasmosis requires improvement, research be carired out with a view to effecting
desirable improvement in efficiency. In this regard, Australia
as a country that has devoted considerable time and resources
to research in related field, might be asked to assist.
3. That in respect to tick infestation as such, extension
programmes bo implemented in the Region aimed at teaching
a greater awareness of the losses caused by cattle ticks and
methods for their control.
4. That in view of the Thailand experience of Babesiosis
under conditions that indicale the possible involvement of
a vector other than B. microplus research aimed at determining whether blood sucking flics arc capable of transmitting the disease be undertaken as soon as practicable.
AVIAN LEUCOSIS AND MAREK'S DISEASE
in
Considering that precise figures have not been collected
the Region to determine the incidence and economic
— 237 —
importance of Avian Leucosis and Marek's Disease either
together or separately but that Marek's Disease particularly
is regarded as a most important cause of loss in countries
with well developed poultry industries and has occurred
in other countries in the region in imported chickens where
it is regarded with concern ;
And recognising that at present neither treatment nor
specific control measures are available although results of
recent research give hope for the future in the case of
Marek's Disease by way of vaccination and selection of
genetically resistant strains of birds ;
The
Conference
recommends
that
:
1. Each country should establish as precisely as possible
the incidence of the two conditions Avian Leucosis and
Marek's Disease in their poultry populations and determine
the economic importance of each ;
2. Research bo devoted to the development of more easily
applied tests than are available at present to enable the
two conditions to be differentiated more accurately ;
3. Each country exporting chickens should provide proper
facilities and the necessary funds to initiate or intensify
essential research work on Marek's Disease, directed towards
development of an economical and effective vaccine and
selection of strains of birds genetically resistant to the
disease ;
4. Meanwhile exported chickens should be derived from
farms with a favourable history of Avian Leucosis and
Marek's Disease ;
5 . Vaccine producers take precautions to
poultry vaccines are free of contamination
Leucosis and Marek's Disease viruses.
ensure that
with Avian

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