Researchers say they have identified genes that make some African malaria-carrying mosquitoes resistant to insecticide, and hope the breakthrough could boost efforts to prevent the deadly disease.
Knowing which genes help the mosquitoes dodge pesticides could point to ways to make better ones that are safer for people, too, said Charles Wondji of the Liverpool School of Tropical Medicine and colleagues.
"We expected to find that different species and populations would have different groups of genes responsible but they are very similar," Wondji said in a statement.
"This is encouraging news because it means that work to overcome resistance in one species is likely to be effective against the other."
Malaria is one of the deadliest diseases worldwide, killing 880,000 people a year, mostly children under age five.
A parasite transmitted by mosquitoes causes the disease, and it has become resistant to some drugs. Work to develop a vaccine has been slow.
Killing mosquitoes with insecticides is one way to prevent malaria but finding potent, low-cost chemicals safe for humans is difficult, Wondji and his colleagues said.
In their study published in the journal Genome Research, the team studied strains of the mosquito Anopheles funestus that are both susceptible and resistant to a commonly used insecticide.
This allowed them to link defense against insecticides to two genes in a family of genes known as P450, considered a first line of resistance to toxins.
Importantly, this gene family has also been associated with resistance in the other major malaria-causing mosquito strain in Africa, suggesting that a well-designed insecticide could make a big impact in tackling the disease.
And because humans do not have these particular genes, scientists may be able to develop new chemicals to kill mosquitoes that are not poisonous to people, the researchers said.
"Routine use of these molecular markers for resistance will provide early warning of future control problems due to insecticide resistance," said Hilary Ranson of the Liverpool School of Tropical Medicine, who helped lead the study.
"(This) should greatly enhance our ability to mitigate the potentially devastating effects of resistance on malaria control."