Mosquitos more attracted to those with malaria

[Guest guest]

I've often wondered at the eerie stories where people with lyme keep

getting re-bitten. Now I think we know its not coincidence. Ticks,

like mosquitoes, may be more attracted if you're already infected.

Helps spread more bugs.

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Malaria remains a devastating problem in Africa and understanding the

factors affecting its transmission remains a crucial part of the

effort to combat the disease. A new study published in the premier

open access journal PLoS Biology conducted in Western Kenya by

Koella and colleagues now reveals that mosquitoes are more attracted

to children with the infectious stages of malaria than to those

infected with non-transmissible forms of the disease or to uninfected

people.

The question of whether malaria increases your chances of being

bitten by a mosquito has long stalled scientists because of numerous

confounding factors. Sweat, breath odour, and high body temperature

all increase mosquitoes¡¦ blood lust, and no previous study had been

able to isolate the effect of just the parasite. To measure how

attracted the mosquitoes were to the participants, the researchers

set up a chamber of uninfected female mosquitoes surrounded by tents

containing the children - one already infected with transmissible

malaria, one infected with the non-transmissible asexual stage of the

disease, and one with no infection. A device called an olfactometer

wafted the odours of each participant towards the mosquitoes.

Researchers measured which child most attracted the hungry bugs.

Koella et al. found that individuals attracted significantly more

mosquitoes if they had the infectious stage of the malaria parasite.

Moreover, when the children were treated with antimalarial drugs,

there was no difference in the subsequent attractiveness of the

participants.

It is already known that mosquito biting rates greatly influence the

spread of malaria. Now Koella and colleagues have shown that the

parasite itself manipulates the biting behaviour of the mosquito

vector when it is ready for a new host. Such manipulation could have

a profound effect on the epidemiology of disease and, if it is not

considered, could lead to severe biases in the estimates of the

intensity of malaria transmission