September 10, 2013
Chemical Compound Could Mask Human Smells From Mosquitoes
[ Watch the Video: Masking Our Scent So We Don’t Get Bit ]
redOrbit Staff & Wire Reports - Your Universe OnlineMosquitoes are arguably the most dangerous insects on Earth, but researchers from the USDA’s Mosquito and Fly Unit in Gainesville, Florida are currently working on a new form of protection against the blood-sucking, disease-carrying pests.
In research presented at the 246th National Meeting & Exposition of the American Chemical Society, research chemist Dr. Ulrich Bernier described how he and his colleagues discovered substances that occur naturally on human skin and block mosquitoes’ ability to smell potential victims.
Dr. Bernier’s research was inspired by what he calls the need for better ways to combat the small, midge-like flies that transmit diseases such as malaria, encephalitis, yellow fever and West Nile virus. The insects are more deadly to humans than any other animal, the researchers said, and are responsible for an estimated one-million fatalities worldwide each year. Furthermore, they have been known to transmit heart worms to pet dogs and cats.
“Repellents have been the mainstay for preventing mosquito bites,” he explained. “The most widely used repellant, DEET, is quite effective and has been in use for a long time. However, some people don't like the feel or the smell of DEET. We are exploring a different approach, with substances that impair the mosquito's sense of smell. If a mosquito can't sense that dinner is ready, there will be no buzzing, no landing and no bite.”
Female mosquitoes suck blood in order to obtain a protein needed in order to produce fertile eggs, and are capable of smelling people from more than 100 feet away, the researchers explain. Dr. Bernier and his colleagues at the Mosquito and Fly Unit have been researching mosquito repellents for over the past seven decades, and in the 1990s they uncovered data on substances secreted through human skin and formed by bacteria on the skin that can make some men and women more attractive to the blood-sucking insects than others.
According to the research team, a person’s scent comes from hundreds of different compounds on the skin, many of which are emitted through sweat. In order to identify which compounds mosquitoes found attractive, Dr. Bernier’s team used a special mosquito cage divided by a screen and sprayed various compounds into one side of the cage. They documented what impact each substance had on attracting mosquitoes.
The researchers found that lactic acid (a common component of sweat) attracted 90 percent of the mosquitoes to the screen. Other compounds drew little to no reaction out of the insects, however. The mosquitoes did not take flight or appeared to be confused after being exposed to those substances.
“If you put your hand in a cage of mosquitoes where we have released some of these inhibitors, almost all just sit on the back wall and don't even recognize that the hand is in there,” Dr. Bernier explained. “We call that anosmia or hyposmia, the inability to sense smells or a reduced ability to sense smells.”
He reported that a group of chemical compounds, including 1-methylpiperzine, can actually block a mosquito’s sense of smell – a discovery which could help experts understand why the bugs tend to target some individuals while ignoring others. The substances are said to have a molecular architecture found in ingredients of several different products, and appear to be suitable for use in lotions, cosmetics, and clothing.