Fighting Malaria With Scent

Researchers have mapped out the cells of the malarial mosquito's special "nose" that helps it zero in on human prey.

The scientists think the advance could help develop new and improved mosquito repellants and attractants to fight malaria, one of the world's most widespread and notorious diseases.

The "nose" is actually a sensory organ called the maxillary palp, shown above. Detailed in the in a recent online edition of the journal Current Biology, the map shows unique receptor cells that detect carbon dioxide and octenol, key chemical signals that the insects use to find human prey.

"These receptors are highly sensitive, which suggests that the maxillary palps may serve as the malaria mosquito’s long-range detection system," said co-author Tan Lu, a graduate student at Vanderbilt University in Nashville, Tenn. While Lu and his colleagues haven't verified the claim for certain, Laurence Zwiebel, a biologist at Vanderbilt, said the mosquito would be hapless without it.

Compared to the mosquito’s fuzzy antennae, which detect hundreds of different compounds, the study found that the maxillary palps detect only a handful of specific chemicals.

"The amazing thing that we found was that all the sensory hairs that line the bottom of the maxillary palps are identical," Zwiebel said. They are all attached to three neurons: one which is tuned to detect carbon dioxide; one which is tuned to detect octenol; and one which serves to enhance general olfactory reception.

—LiveScience Staff

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Credit: Zwiebel Laboratory/Vanderbilt University