(Montreal) A mosquito net coated with a new insecticide that prevents mosquitoes from flying has reduced the incidence of malaria in children by about 40%, according to a new project carried out in Tanzania and involving Canadian researchers.
Posted at 7:54 p.m.
The study was conducted over two years among some 39,000 Tanzanian households. In randomized trials with over 4,500 children aged six months to 14 years, mosquito nets impregnated with chlorfenapyr and pyrethroids reduced the prevalence of malaria by 43% and 37% for the first and second year respectively, compared to traditional mosquito nets which are strictly coated with pyrethroids.
The use of nets coated with chlorfenapyr also reduced clinical episodes of malaria by 44% over the study period, and the number of carrier mosquitoes caught by 85%.
“By testing these new types of mosquito nets coated with two insecticides, we were able to verify whether the new mosquito nets were effective in controlling malaria in areas where resistant mosquitoes are found,” explained Professor Manisha Kulkarni, from the School of Epidemiology. and Public Health from the Faculty of Medicine at the University of Ottawa.
“And we found that this new type of mosquito net which has two insecticides […] has reduced malaria infections in children in areas where the mosquito population has developed resistance (to traditional insecticides). »
Chlorfenapyr is the first new class of insecticide approved to fight malaria in 40 years.
Mosquito nets impregnated with insecticides have greatly contributed to reducing the scourge of malaria in sub-Saharan Africa for the past ten years. However, there has been a slowing down, and even a reversal, of this trend in recent years, in particular because the Anopheles mosquitoes whose bite spreads malaria are increasingly resistant to the pyrethroid insecticides with which traditional mosquito nets are impregnated.
Pyrethroids, which were developed in the 1980s, paralyze mosquitoes by targeting their nervous system. Chlorfenapyr, on the other hand, causes cramps in the wing muscles of insects by attacking energy production at the cellular level. Pinned to the ground, the mosquito eventually dies.
“So it’s a very different mechanism, which means it’s very unlikely that there’s cross-resistance to this new class of insecticides,” said Professor Kulkarni, whose ecological models of carrier species were used to develop the research protocol and to randomize the trials. These new mosquito nets should therefore be effective for a very long time. »
If the new nets are more expensive than the old ones, the researchers calculate that the reduction in costs for the health system that will result from their use will generate a net benefit.
The new tool could give a major boost to the fight against malaria in sub-Saharan Africa. However, further research is needed to determine whether it can be scaled up and to develop resistance management strategies to ensure that it remains effective over the long term.
The nets will now be tested in Benin to study their effectiveness in a different context, which could ultimately lead to their recommendation by the World Health Organization.
In addition to the University of Ottawa, the study was carried out by the London School of Hygiene and Tropical Medicine, the National Institute for Medical Research and Kilimanjaro Christian Medical University College, Tanzania.
The findings of this study are published by the prestigious medical journal The Lancet.