28 May, 2011

Your feet stink, so mosquitoes must love you

In accordance with my previous post, more evidence has been found that mosquitoes are attracted to  bodily odour. This time, scientists says it is feet odour.

Before a mosquito comes in for a “fly-through” meal, it first has to feed on a sugary substance, usually from a flower. Then it uses carbon dioxide from a potential target’s breath to locate a blood-filled host from up to 30 feet away. But as the hungry insect nears, malaria-bearing veer away from the face and move towards the feet, where they prefer to feed. Researchers have long believed that messing with the mosquitoes’ sense of smell could hold the key to stopping their blood-lust.

Remco Suer started by experimenting on the African malaria mosquito, . He knew that prior research had found that human foot bacteria produce about ten separate odours, some more attractive to mosquitoes than others. Suer, who did the study as part of his doctorate in at Wageningen University in the Netherlands, showed that these foot odours are detected by neurons that control smell, which are present underneath hair-like structures on the mouth parts of the malaria mosquito.

Suer tested their sense of smell in the laboratory by pumping additional CO2 into a container to simulate human breath, then added a high concentration of five different foot odours and found that the mosquitoes were unable to react to the CO2 for several seconds. The sole-ful odours actually stopped mosquitoes from sensing CO2 from breathing — which could be a reason why malarial mosquitoes divert when honing in on a person and move instead to the feet at close ranges.

But Suer pointed out that this doesn’t mean people with especially funky feet are more likely to get nibbled on.

“It is not the amount of odors produced, but which particular odors and ratio between them that makes a difference. Finding these odors and their respective ratio’s brings us one step closer to manipulating the mosquito’s behavior.”

It is this short-range orientation shift that may be used against the mosquito’s sensitive nose.

Suer thinks that better traps could be built luring mosquitoes into places that smell like feet — and away from transmitting disease to human targets — and started In2Care, a company he hopes will take the research and transform it into a low-tech product to help people in places where malaria is a danger.

DNA, Humans, Nature, Neuroscience, Weblog