UC Davis researchers have identified the sweet, sweet cologne that draws blood-feeding Culex mosquitoes (which transmit West Nile virus and other diseases) to humans. Apparently the secret is, as they say, in the semiochemical:
Entomology professor Walter Leal and postdoctoral researcher Zain Syed found that nonanal (sounds like NAWN-uh-nawl) is the powerful semiochemical that triggers the mosquitoes' keen sense of smell, directing them toward a blood meal. A semiochemical is a chemical substance or mixture that carries a message.
Birds, the main hosts of mosquitoes, serve as the reservoir for the West Nile virus, Leal said. When infected mosquitoes take a blood meal, they transmit the virus to their hosts, which include birds, humans, horses, dogs, cats, bats, chipmunks, skunks, squirrels and domestic rabbits.
The Davis research is based on tests of hundreds of naturally occuring compounds emitted by people and birds. They collected the odors from 16 adults from differnt backgrounds.