- Study shows children sleeping under bed netting treated with two pesticides contract malaria at less than half the rate of those with single-treated netting
- Expert says study is proof that such nets with two or more insecticides should have been approved for widespread use a long time ago
- Mosquitoes have evolved to tolerate pyrethroids - a class of insecticides the world has relied on for preventing malaria
Newswise — A new study on the use of insecticides on anti-mosquito bed-netting has revealed that thousands of people have needlessly contracted malaria due to policy failure, according to an expert at University College Cork (UCC) in Ireland. The study highlights the importance of having a proper policy in place for the use of insecticides to ensure that they are used effectively to combat malaria transmission and protect people from the disease.
In an article published in the prestigious journal The Lancet, Professor Gerry Killeen, AXA Research Chair in Pathogen Ecology at University College Cork (UCC) states that a large-scale trial of bed nets treated with two insecticides, as opposed to just one, clearly demonstrates the significant impact that combinations of active ingredients can have on reducing the burden of malaria in rural Africa. The study highlights the importance of utilizing multiple insecticides in malaria control efforts to effectively combat the disease and protect people from its devastating effects.
The study revealed that since mosquitoes have evolved to tolerate pyrethroids, a class of insecticides that has been widely used for preventing malaria, children sleeping under bed nets treated with only this active ingredient still contract malaria once a year on average. However, children with bed nets treated with dual insecticides become ill at only half that rate. This highlights the need to use multiple insecticides to combat malaria and to prevent the evolution of resistance in mosquitoes to any single insecticide.
Prof Killeen, who wrote the commentary with Dr Seynabou Sougoufara at Keele University, says this landmark paper also proves the point that such nets with two or more insecticides should have been approved for widespread use a long time ago.
“By using two or more active ingredients, such combination nets can decisively kill off insecticide-resistant mosquito variants before they have the opportunity to multiply, thus preventing resistance from becoming established across entire mosquito populations in the first place,” Prof. Killeen commented.
According to Professor Killeen, pyrethroids are crucial for public health as they are the standard treatment for bed nets and the only insecticide class that can be safely dispersed into the air as a repellent vapor to protect people living in malarious areas when they are awake and active outside the protective reach of their bed nets. He highlights the importance of finding new insecticide combinations to preserve the effectiveness of pyrethroids in preventing malaria.
“It is unclear at present whether the pyrethroid resistance genie can be put back in the bottle but that’s exactly why our ongoing work in collaboration with the Ifakara Health Institute and Sokoine University of Agriculture in Tanzania is so important,” Prof. Killeen said.
According to Professor Killeen, in order to maintain the effectiveness of insecticides in preventing malaria, it is important to continue researching new insecticide combinations that can be used to select for pyrethroid susceptibility traits in mosquitoes. He and his team are currently surveying wild conservation areas in southern Tanzania to find malaria vector mosquitoes that have escaped insecticide pressure by feeding on wild animals rather than humans or livestock, in order to understand how to preserve the effectiveness of insecticides in preventing malaria.
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