Work in the bush? Want to be invisible to mosquitoes?
By Anthony Capkun
September 9, 2013 – In an advance toward providing people an invisibility cloak against mosquitoes, scientists have discovered substances that occur naturally on human skin and block mosquitoes’ ability to smell and target us.
Ulrich Bernier, Ph.D., discussed this topic at the 246th national meeting & exposition of the American Chemical Society (ACS), saying that while repellents (i.e. DEET) have been the mainstay for preventing mosquito bites, “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”.
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% of the mosquitoes to the screen. Other compounds, however, didn’t inspire many mosquitoes to take flight… some even seemed confused.
“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. We call that anosmia or hyposmia, the inability to sense smells or a reduced ability to sense smells,” explained Bernier.
He said a group of chemical compounds block mosquitoes’ sense of smell. This may help explain why mosquitoes fly toward some people but not others. The substances have a molecular architecture found in ingredients in dozens of medicines and other products, and appear suitable for use in products already incorporating mosquito repellants.