Mosquitoes seem to have adapted to the widespread use of bed nets by shifting their "peak period of aggression", a new study reveals.
The widespread use of insecticide-treated nets has been credited with a sharp drop in the number of malarial deaths, especially in sub-Saharan Africa but researchers in two African villages where every household was given a net found that the insects changed their period of "peak aggression" from the middle of the night to the pre-dawn hours.
The study in the West African nation of Benin found that three years after the nets were introduced two-thirds of mosquito bites were taking place outdoors as compared to 45 percent when the French researchers began.
However, Corbel warned against extrapolating wider conclusions from such a geographically-limited study.
Until now concern over the long-term viability of nets coated in insecticide has centred on mosquitoes developing resistance to the chemicals.