Cape Town - A new “super mosquito” has evolved in West Africa which is resistant to insecticide-treated mosquito nets.
This could have a big impact on anti-malaria programmes which distribute mosquito nets as a cheap and effective way of protecting people, particularly children, from contracting the disease which kills around 600 000 people a year.
Researchers from the University of California Davis announced this week that they had established that the super mosquito hybrid evolved from the interbreeding of two malarial mosquito species in Mali.
The researchers said their findings provided convincing evidence that man-made changes in the environment, in the form of the introduction of insecticides, had altered the evolutionary relationship between the two mosquito species.
Lead author Gregory Lanzaro said they described the new mosquito as “super” because it could survive exposure to the insecticides on the treated mosquito nets.
“What we provide in this new paper is an example of one unusual mechanism that has promoted the rapid evolution of insecticide-resistance in one of the major malaria mosquito species.”
The two mosquitoes that interbred were Anopheles gambiae and Anopheles coluzzii.
Lanzaro said the insecticide resistance had come as no surprise. “Growing resistance has been observed for some time. Recently it has reached a level at some localities in Africa where it is resulting in the failure of the nets to provide meaningful control, and it is my opinion that this will increase.”
He believes these nets have saved many thousands, and possibly tens of thousands, of lives in Mali alone.
“Now there’s an urgent need to develop new and effective malaria vector control strategies,” Lanzaro said.
Some strategies include developing new insecticides and biological agents, including mosquito-killing bacteria and fungi. There is also work being done on the genetic manipulation of mosquitoes aimed at either killing them or altering their ability to transmit the malaria parasite.
The World Health Organisation’s (WHO) World Malaria Report said deaths from malaria worldwide had decreased by 47 percent since 2000.
Much of the decrease was attributed to the insecticide-treated bed nets.
The WHO said in Africa the malaria death rate had decreased by 54 percent. About 90 percent of malaria deaths occur in Africa.
It said about 3.2 billion people – almost half the world’s population – are at risk of malaria.
In 2013 there were an estimated 584 000 malaria deaths. Most of the deaths were among children under five.
Cape Times