Impregnated mosquito nets: IRD`s weapon against malaria

From research
to development
Impregnated mosquito nets:
IRD’s weapon against malaria
In a quarter of a century, mosquito nets have seen their role stepped up from
merely ensuring comfort to becoming a key asset in the fight against malaria.
Behind this success story, an invention by IRD’s researchers: insecticidetreated mosquito nets.
The nets were first industrialised in the 2000s and are advocated by the WHO.
They now protect 80% of households from mosquito bites in risk areas in
Africa. It’s estimated that they have halved the number of malaria cases and
reduced child mortality by 20%.
Malaria has plagued humankind since ancient times
(Tutankhamen apparently died from it 3,000 years
ago). Western countries managed to eradicate it during the first half of the twentieth century. However,
the disease was still rife in Africa, Asia and America
in the early 1980s. Worldwide eradication efforts failed as strains of the parasite developed resistance to
drugs. Massive spraying of DDT1-based pesticides
was an environmental disaster. The scientific community had come up against a brick wall.
Malaria-bearing mosquito on an impregnated mosquito net. (IRD/M. Dukhan)
An idea dating back to 1983
the sleeper from bites and have a lethal effect on
It was in this context that, in 1983, Dr P. Carnevale
the malaria-bearing mosquito. However, there was
and his team from Orstom, which later became the
room for improvement in the manufacturing process
IRD, came up with the idea of impregnating mosquito nets with insecticide. Until then, the nets had
only provided a relative level of physical protection.
The slightest hole or contact with skin erased its
efficiency. However, when treated with insecticide2,
at the time.
In the 2000s: a new concept emerges
Fifteen years later, mosquito nets were back on the
the nets form a virtually impenetrable defence me-
agenda when IRD researchers, working under the
chanism. IRD tested the first prototypes in trials in
direction of Dr P. Guillet, finally brought textile ma-
Bobo-Dioulasso (Burkina Faso). The benefits of the
nufacturers and agrochemical specialists together
nets became apparent on two levels: they protect
for the first time. A new concept emerged from their
3
discussions: mosquito nets with long-lasting insecticide treatment. Their protective treatment lasts up to
20 washes and remains effective for at least 3 years.
Trials conducted around the world demonstrated
long term effects which reduced the burden of malaria, with 50% fewer cases and a decrease of child
mortality rates by 20%.
It took just a few years for these long-lasting insecticide-treated nets to become the prime weapon
in the fight against the disease. The World Health
Organisation (WHO) recommends their widespread distribution through the national control programs run in most African countries concerned.
The WHO estimated that in 2015, 67% of Sub-
IRD, the scientific reference on mosquito nets
Saharan households were equipped with insec-
Industrial stakeholders soon realised the extraordi-
ticide-treated mosquito nets. 154 million mos-
nary potential of the market and quickly picked up on
quito nets were issued on the continent that year.
the invention. The IRD remains the reference from a
scientific viewpoint. Its insect pest control laboratory
(known as LIN) is a WHO collaborating centre.
Researchers are now working to make this form of
protection even more effective and practical. In 2004,
the IRD registered a patent (JM Hougard and C Pennetier) for a new combination of insecticides, aimed at
overcoming mosquito’s resistance.
1. Dichlorodiphenyltrichloroethane
2. From the pyrethroid family, low toxicity for human beings and effective at low doses.
3. Darriet et al. 1984. Evaluation of the efficacy of permethrin impregnated
intact and perforated mosquito nets against vectors of malaria. World
Partners
Burkina Faso : Institute for Research in
Science of Health (IRSS)
Health Organization, WHO/VBC/84.899, WHO/MAL/84.1008, 19 p
International Affairs Service
Benoît Martimort-Asso : +33 (0)4 91 99 93 31
Contacts
[email protected]
Ivory Coast : Institut Pierre Richet (IPR),
Benin : Centre de recherche entomologique
de cotonou (CREC)
Cameroon : Organization for the Coordination
of the fight against Endemic Diseases in
Central Africa (OCEAC)
44 boulevard de Dunkerque
CS 90009
13572 Marseille Cedex 02
France
www.ird.fr
© IRD/DCPI, mars 2016 - Conception et réalisation graphique : L. CORSINI
The LIN lab in Montpellier. (IRD/F. Chandre)