Mosquitoes are more than just an annoyance—they play a major role in spreading some nasty diseases. Mosquitoes are largely to blame for transmission of malaria, a group of diseases called arboviral encephalitides that includes West Nile virus, dengue fever, Rift Valley fever, yellow fever, and other illnesses. And cold weather isn’t necessarily protection. Often winter simply drives the pests indoors, where they can attack at their leisure.
Now, however, scientists are coming to a better understanding of how the insects find and select their targets: it’s our breath. Not bad breath; the mosquitoes smell the carbon dioxide we exhale. Once close to humans, the ladies—only female mosquitoes bite—use different odors to zero in on exposed skin areas. That means that anything a human has touched has the power to draw mosquitoes. The mosquitoes use the same organ, called the maxillary palp, to detect both human breath and human skin, surprising researchers who had assumed the two functions were handled by separate structures.
"For many years we had primarily focused on the complex antennae of mosquitoes for our search for human-skin odor receptors, and ignored the simpler maxillary palp organs," said stud author Anandasankar Ray in a statement. The study is the first to identify precisely which mosquito olfactory organs are responsible for the insects’ attraction to human skin.
The next step, say researchers, is to use these findings to help develop ways to cloak humans and render us invisible to mosquitoes, or to lure them away from people and possibly into traps. This is particularly important in areas of the world where mosquito-borne diseases are a major public health issue. Currently mosquito nets, physically preventing mosquitoes from getting to people, are the primary tool of malaria control, but masking humans and luring the mosquitoes away from them may prove more effective overall. In fact, substances that occur on human skin naturally have already been determined to repel mosquitoes, though not as much as other compounds attract them. This finding can be used to develop a better bug repellant in the future.