How to trick the mosquito's nose
Malaria control at the molecular level
Illustration by Dominic Doyle
Step 1: To trick the mosquito’s “nose,” scientists first have to find out how the insect “smells,” in order to understand how it identifies its prey. They do this by scanning the mosquito genome for genes that encode odorant receptors, proteins found primarily in sensory hairs, called sensilla, on the mosquito's antennae. Some of these receptors bind specifically to chemicals found in human sweat. At least one receptor gene is expressed only in the antennae of the female mosquito. Only female mosquitoes bite humans, and the expression of this gene rises when they are “hungry” for a human blood meal.
Step 2: The next step is to identify chemical compounds that bind to this and other mosquito odorant receptors. Inserting the mosquito genes into the fruit fly and other model systems makes them easier to study. Researchers were able to screen about 350 different aromatic compounds found in human sweat. One of them, 4-methylphenol, strongly activated the female-specific receptor. The scientists are now looking for other non-toxic compounds that attract, repel or simply confuse the mosquito’s olfactory system. These compounds will be tested for their effect on the behavior of live mosquitoes.
Step 3: Ultimately, the researchers hope to develop long-lasting combinations of synthetic compounds that either attract or repel the female mosquito. Repellants could be embedded in mosquito netting to prevent the insect from finding her sleeping human target, while attractants could be used to draw her to pesticide-containing “traps.”
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