Wetenschap - 30 mei 2013

Human smells better to the malaria mosquito

Malaria-carrying mosquitoes prefer worn HEMA tights.
Research opens up prospect of new method of combatting malaria.

Mosquitoes infected with malaria are more strongly attracted to humans than their uninfected fellows. This finding came out of research on which Wageningen and Nijmegen entomologists published an article in PLoS ONE in May. The research could lead to an effective method of trapping malaria mosquitoes with the help of odours.
For some time there have been suspicions that the behaviour of a mosquito changes once it has been infected with the malaria parasite, explains first author Renate Smallegange. From an evolutio­nary point of view, it is quite logical that parasites do their best to get their carriers to give them a helping hand. Smallegange: 'But we are the first to provide evidence.'
In the course of the experiment the researchers themselves counted how often mosquitoes landed on pairs of HEMA tights, some of the unworn and others worn for 20 hours. The tests were done in a specialized Nijmegen laboratory from which the mosquitoes could not escape. The infected mosquitoes showed a preference for human odours three times as often as the uninfected insects.
Resistant parasites
Every year 770,000 people still die of malaria, while our arsenal of weapons against the disease is dwindling. 'In the fight against malaria we are really standing with our backs to the wall,' says Willem Takken, personal professor of Entomology. 'Worldwide parasites are fast becoming resistant to drugs and mosquitoes to insecticides. We have got to develop alternatives in the short term.'
The human odours that specifi¬≠cally attract malaria mosquitoes form a powerful weapon for the fight against malaria. In their follow-up research, the scientists therefore hope to identify the substances that specifically attract the infected mosquitoes. Traps containing these odours could 'make a big dent in the rate of transmission.'