Sweating the Details on Why Mosquitoes Bug Us
ALLISON AUBREY reporting:
This is Allison Aubrey.
When it comes to mosquitoes and their discriminating biting habits, there's one age-old question.
Ms. JENNIFER LaROCHE(ph): Why is it that some people like me gets bitten where others, like my husband, does not and we're sitting right next to each other?
AUBREY: Jennifer LaRoche and her husband are avid campers.
Ms. LaROCHE: I can wind up with 30 mosquito bites and he'll wind up with zero. So why does that happen?
AUBREY: We put the question to a top mosquito researcher.
Mr. ULRICH BERNIER (USDA Researcher): The reason that some people are more attractive to mosquitoes than others has to do with the chemicals that each of these people or each individual is producing.
AUBREY: Ulrich Bernier runs a USDA research lab in Gainesville, Florida.
Mr. BERNIER: Different people tend to omit chemicals at different levels coming off of their skin. And some of these chemicals that we produce attract mosquitoes to us and some of these chemicals that we produce actually hide us from mosquitoes.
AUBREY: So the idea is that when you hear people say, `Hey, I always get bitten and my husband never does,' there is some truth to that.
Mr. BERNIER: That is correct. We believe that diet plays a large role in the chemicals that are produced, that come out of the skin.
AUBREY: Bernier explains our bodies make a number of chemicals as byproducts of the food we eat. Some, it turns out, are appealing to mosquitoes. For instance, acetone is a hit. That's a breakdown component of fat burning. And lactic acid, a byproduct of exercise, is attractive, too. Bernier says back in 1997, when he combined traces of these chemicals into a petri dish in his lab, the results sounded something like this.
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Mr. BERNIER: We noticed that the mosquitoes that were sitting around in the cage went up into the air and flew upwind into the trap that contained this attracting blend.
AUBREY: Wow. And so what was your reaction?
Mr. BERNIER: At that moment we realized that we were on to something important.
AUBREY: The hope is that once these attractants are pinned down, mixtures of these chemicals can be used to build more effective mosquito traps. Bernier's lab is currently working on a prototype for the US military to protect soldiers in the field, which they expect to have ready within a year.
In the meantime, as people look for better ways to protect themselves, one good option is clothing that repels mosquitoes. Originally developed for military uniforms, consumer lines were approved two years ago.
Mr. SCOTT MITCHELL (Store Manager, REI): Right here we'll see we have your basic sun hat and we have bandanas and we have a baseball-style cap.
AUBREY: So here, the repellents, the chemical's built right into the hat here.
Mr. MITCHELL: Yes. The whole garment is impregnated with the chemicals to help the repellency.
AUBREY: Scott Mitchell is a store manager with the outdoor retail chain REI. He says customers are coming in asking for the clothing.
Mr. MITCHELL: They've just heard that it's a way not to have to put a repellent onto their skin, which is often appealing to the customers.
AUBREY: And research shows the insecticide that's applied--called permethrin--last through about 25 washings. The USDA research lab in Gainesville is currently working on new specs to make soldiers' insecticide-treated uniforms more effective. The challenge is to repel bugs from the areas of the body, such as the hands and the face, that are not covered. Allison Aubrey, NPR News, Washington.
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