Scientists have identified a genetic mutation that causes insecticide resistance in the mosquito that carries malaria. Their findings may pave the way for designing new insecticides.

Mylène Weill of the Université Montpellier II, France, and colleagues found that a single 'letter' change in the mosquito's genetic code is responsible for insecticide resistance, which has significantly hampered efforts to fight the disease.

The researchers report in this week's issue of Nature that 10 highly resistant strains of the West Nile disease-carrier Culex pipiens mosquito, and one resistant African strain of Anopheles gambiae, a mosquito that carries malaria, have the same mutation for insecticide resistance.

The mutation lies in a gene called ace-1, which encodes a key enzyme that is targeted by some insecticides. As a result of the mutation, the enzyme loses sensitivity to chemicals that are widely used as the active ingredient in certain insecticides.

"The discovery of the ace-1 mutation that is responsible for insecticide resistance in mosquitoes opens the way to new strategies for pest management," the researchers write. "The development of new insecticides that can specifically inhibit [the mutant form] will be crucial in overcoming the spread of resistance".

Link to research paper in Nature