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Killer fungus breaks chemical stalemate

The fungus killed mosquitoes resistant to three classes of chemical insecticides commonly used in Africa and could aid anti-malaria efforts

A killer fungus may break the chemical stalemate that is hampering anti-malaria efforts.

Mosquitoes that carry malaria are becoming increasingly resistant to insecticides. In theory, spraying two different types of insecticide at once postpones resistance, as bugs that resist one type are killed by the other. But so far, this strategy hasn鈥檛 worked as the enzymes mosquitoes use to disable one class of chemicals tend to cripple other classes too.

Entomologist Bart Knols and colleagues at Wageningen University in the Netherlands wondered if the same problem would mean insecticide-resistant mosquitoes would be able to fend off a fungus. This was not the case: the fungus killed mosquitoes resistant to the three classes of chemicals commonly used in Africa.

鈥淎s a bonus,鈥 Knols says, 鈥渇ungal infection makes insects that resist pyrethroids susceptible again.鈥 Fungal infection might weaken the insect and its resistance mechanisms. In addition, a smaller dose of chemicals will kill fungi-infected mosquitoes, good news as one of the chemicals is DDT, which persists in the environment.

Journal reference: Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.0908530106 (in press)

Topics: Epidemics / Microbiology