Wetenschap - 10 augustus 2016

‘Odour trap necessary for lasting malaria control’

tekst:
Albert Sikkema

Malaria in Africa has been on a downward trend in the past ten years thanks to the distribution of mosquito nets treated with insecticides, but that decline is now stalling. We need the biological control of mosquitoes with bait, concludes entomologist Willem Takken.

Takken worked with Wageningen and Swiss researchers to develop a trial on the Kenyan island of Rusinga in Lake Victoria, in which odour traps were used successfully to combat malaria. This biological method of mosquito control is needed to further push back the life-threatening malaria parasite, says the Wageningen entomologist.

The number of malaria cases has fallen by 50 percent globally since 2005, notes Takken. That is thanks to mosquito nets treated with insecticides that have been handed out to African people free of charge. ‘This malaria programme, which is paid for by the Global Fund with money from rich industrial countries, has been very successful,’ says Takken. ‘The number of deaths from malaria has fallen from two million a year in 2005 to half a million in 2015.’

Resistent
However, a cause for concern is that the decline in the number of Africans with malaria – currently about 30 percent of the population – has stalled. Takken sees two reasons for this. There are signs that the malaria mosquitoes are becoming resistant to insecticides. Moreover, the mosquitoes are now more likely to bite people outside the home, where they are not protected by mosquito nets.

Takken: ‘Sooner or later the mosquitoes will develop resistance; we have seen that too in the application of DDT. That is why we have opted for this non-chemical prevention method. Our bait imitates the scent of humans. The mosquitoes cannot operate without that bait; they need it to find their food. That means this approach could have a real lasting effect and be a solution for the problem of resistance.’


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