MOSQUITOS…could put down malaria and more.
Mosquitoes ruin countless American picnics every year, but around the world, the whine of these bloodsucking beasts isn’t just irritating—it heralds an epic health problem. More than a million people die each year from the spread of mosquito-borne diseases like malaria, dengue fever, and yellow fever. Attempts to control mosquito populations via insecticides like DDT have had ruinous side effects for nature and possibly human health. Neurobiologist Leslie B. Vosshall has a different solution for stopping the insects and the spread of disease. “I believe the key to controlling mosquito behavior is to better understand how they sense us,” she says.
At their Rockefeller University lab, Vosshall and her colleagues are studying the chemical sensory processes by which mosquitoes choose hosts. How do they sense heat, humidity, carbon dioxide, and body odor? What makes some people more attractive to a mosquito than others? It takes blood and sweat to find out. To study how mosquitoes assess body odor, Vosshall and her teammates might wear nylon stockings on their arms and refrain from showering for 24 hours to create sample smells.
Then comes the hard part. They insert their limbs into the insects’ den to study how mosquitoes land, bite, and feed, and then they document how these behaviors change depending on both the mosquitoes’ genetics and the particular traits of the scientists’ skin. This can mean getting anywhere from one bite to a whopping 400, depending on the experiment. Studying male mosquitoes is more pleasant; since they don’t feed on blood, the lab tests their sense of smell using honey.
Vosshall and her team have also begun to study how genetics contributes to mosquitoes’ choice of a host. With a bit of tinkering, she’s even created a breed that is unable to sense carbon dioxide, an important trigger for the insects. “By using genetics to make mutant mosquitoes, we can document exactly how and why this cue acts to make mosquitoes hunt
humans,” Vosshall says.
Once Vosshall figures out what makes mosquitoes flock to us, she can get to work on making them leave us alone. Many of her lab’s proposed solutions sound simple enough, including bracelets that carry long-lasting repellents or traps that can reduce populations, but the breakthroughs may save millions of lives in the developing world—and a lot of itching everywhere else. —Liana Aghajanian
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