Leishmaniasis: medicinal plants for a neglected disease

Scientific bulletin n° 335 - December 2009
© IRD / Guillaume ODONNE
© IRD / Guillaume ODONNE
L
eishmaniasis is a
frequent health problem
for the Chayahuitas, as for
other Amazonian
communities, particularly in
Bolivia, Peru, Ecuador and
Colombia. WHO estimates
that this disease, in its
different forms1,affects
about 12 million people in
the world, from America
across to Asia, by way of
Europe and Africa. Yet it is
still a neglected disease2.
The main treatments
currently available carry a
certain toxicity and require
hospital follow-up care.
Such services are rare in
the endemic areas where
indigenous peoples such
as the Chayahuitas live.
The Chayahuitas
successfully use local
medicinal plants as
treatments. Aiming to
detect the most effective
therapeutic agents and
explore new ways of
controlling leishmaniasis,
IRD researchers and their
partners3 studied the
Chayahuitas’ perception of
the disease, then recorded
and analysed their healing
practices. They found some
active plants which could
eventually be incorporated
in treatment programmes.
Leishmaniasis:
medicinal plants for a neglected disease
Centre of Soledad, a village of the Chayahuita community in the Peruvian Amazon.
Inset: specimen collecting for biological prospection.
The Chayahuitas, a community in the Peruvian Amazon, live permanently in contact
with the vector of leishmaniasis which is
rife in the forest. Many of them bear the
characteristic scars of sores that this
disease causes. They live far from any
health centres. However, they have a
range of treatments available, inspired
from the local biodiversity. IRD scientists
and their French and Peruvian partners3
have surveyed and assessed the traditional
pharmacopoeias. They succeeded in validating the effectiveness of certain plants
which could eventually lead to an alternative
to present-day treatments, which are toxic
and produce many side-effects.
From plants to medicines
These people are strongly exposed to
leishmaniasis. They identify the disease in
all the forms that affect the skin and the
mucosae, which they call respectively Ta’ta
and Huayani. By analogy with the moist
aspect of the skin ulcers induced by the
disease, most of the 93 people interviewed
during the survey wrongly attribute the
infection to a bite from a leech, an animal
known to live in a humid habitat. As for the
mucosal form, local belief is that a worm in
the nasal cavity nibbles away at night at the
rim of the nostrils and ears.
The Chayahuitas attach great importance
to the moist state of the wound as a characteristic sign of the disease. They administer
their remedies in the form of a powder of
dried plants, or of ash from such plants.
The preparation is applied directly on the
ulceration as a poultice. They make a total
of 53 different plant medicines based on
around 30 plant species.
In vitro analysis of such plants revealed
that six of them show effective action on
Leishmania, the protozoan parasites
responsible for the disease. In these tests,
the researchers focused on the potential
anti-parasitic action of these plants.
However, in their host, the Leishmania
manage to counter the immune system in
order to invade the immune-system cells.
Some plant species found to exert no direct
action on the Leishmania may have an
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CONTACTS:
Geneviève BOURDY
researcher at the IRD
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UMR PHARMACOCH - Pharmacochimie des substances naturelles et pharmacophores redox
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Guillaume ODONNE
doctoral student at the UMR152
(IRD and Université Paul Sabatier – Toulouse III) and at the
Université Antilles Guyane
[email protected]
UMR Ecologie des Forêts de
Guyane - EcoFoG (ENGREF,
INRA, CIRAD, CNRS and
Université des Antilles et de la
Guyane)
Address:
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French Guiana
REFERENCES:
immunomodulatory effect 4 that helps
control this parasitic infection.
The Chayahuitas: a population at risk
The Chayahuita community comprises
about 16 000 people spread over the NorthEast part of Peru. They currently lead a
sedentary way of life, preferring to settle on
river sides, and practise slash-and-burn
agriculture. However, their cultural habits
linked to their past way of life −in small
communities in a close relationship with the
forest− are still alive. They are therefore in
permanent contact with leishmaniasis,
transmitted to humans through biting by
female Phlebotominae, small sand flies
which live at the foot and in the crown of
trees, or in leaf litter.
Leishmaniasis: a neglected disease
Leishmaniasis is a neglected, re-emerging
disease. Medical practitioners had thought
that it was under control. The reality is that
an increasing number of cases are
observed, owing in particular to deforestation which brings human populations into
contact with the insect vector. Each year it
affects 1.5 to 2 million people in the world
and is now a major public health problem in
Latin America, especially so in that it hits
people who have low economic resources,
like the Amerindian peoples.
With no access to the rare leishmaniasis
treatments available, which necessitate
hospital care and besides have toxic
effects, the Chayahuita community has
taken advantage of the Amazon’s rich
biodiversity to develop effective plant medicines. These treatments based on medicinal plants have now been identified and
their activity has been characterized. In the
long term they could be standardized and
incorporated in health care strategies..
Gaëlle COURCOUX – DIC
Translation – Nicholas FLAY
1. T hree forms of leishmaniasis exist: cutaneous,
muco-cutaneous and visceral.
2. Malaria, tuberculosis, sleeping sickness, Chagas’
disease, leishmaniasis and so on. These are known
as neglected diseases because they attract little
attention from medical research.
3. This research work was conducted in collaboration
with members of the Chayahuita communities of
Soledad and Atahualpa in Peru, researchers from
the Universidad Nacional Mayor de San Marcos
and the Universidad Peruana Cayetano Heredia in
Lima, Peru, the CNRS, the Université des Antilles
et de la Guyane and Université Paul Sabatier in
Toulouse.
4. S timulates or depresses the body’s immune
responses.
odonne guillaume,
bourdy genevieve, castillo d.,
estevez yannick, lanchatangoa a., alban-castillo j.,
deharo eric, rojas r., stien d.,
sauvain michel. ta’ta’, huayani :
perception of leishmaniasis and
evaluation of medicinal plants
used by the chayahuita in peru.
part ii. Journal of ethnopharmacology, 2009, 126 (1),
p. 149-158.
doi:10.1016/j.jep.2009.07.015
KEY WORDS:
Leishmaniasis, medicinal plants,
traditional pharmacopoeias
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Young woman serving Masato, beer made of fermented
manioc.
© IRD / Alain Fournet
© IRD / Guillaume ODONNE
Scientific bulletin n° 335 - December 2009
For further information
Muco-cutaneous lesions caused by leishmaniasis.
Gaëlle Courcoux, coordinatrice
Délégation à l’information et à la communication
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