New cloak hides man from mosquito sight

In an advance toward providing mosquito-plagued people, pets and livestock with an invisibility cloak against these blood-sucking insects, scientists today described discovery of substances that occur naturally on human skin and block mosquitoes' ability to smell and target their victims.

The presentation was among almost 7,000 scheduled here this week at the 246th National Meeting & Exposition of the American Chemical Society, the world's largest scientific society. Thousands of scientists and others are expected to attend the sessions, being held in the Indiana Convention Center and downtown hotels.

Ulrich Bernier, Ph.D., who gave the talk, cited the pressing need for better ways to combat mosquitoes. Far from being just a nuisance, mosquitoes are more deadly to humans than any other animal. Their bites transmit malaria and other diseases that kill an estimated one million people around the world each year. In the United States, mosquitoes spread rare types of encephalitis, an inflammation of the brain. They also transmit heart worms to pet dogs and cats.

Female mosquitoes, which suck blood to obtain a protein needed to produce fertile eggs, can smell people from over 100 feet away. The Mosquito and Fly Unit at the A person's scent, Bernier explained, comes from hundreds of compounds on the skin, many emitted through sweat and others produced by bacteria. To identify which of these attract mosquitoes, Bernier and colleagues used a special mosquito cage divided by a screen. They sprayed various substances into one side of the cage, and documented the effects in attracting mosquitoes.

Some compounds, like lactic acid—a common component of human sweat—were definite mosquito lures, drawing 90 percent of the mosquitoes to the screen. With other compounds, however, many of the mosquitoes didn't even take flight or seemed confused.


/AzerTAg/