A spray or lotion that makes humans undetectable to mosquitoes could soon be available, after U.S. scientists discovered cloaking compounds found naturally on human skin.
"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," said U.S. Department of Agriculture chemist Ulrich Bernier, in a statement released Monday following a press briefing at the American Chemical Society national meeting in Indianapolis.
"If a mosquito can’t sense that dinner is ready, there will be no buzzing, no landing, no bite," he said.
Bernier and his colleagues at the USDA mosquito and fly unit announced they had identified 24 compounds, found naturally in trace amounts on human skin, that when sprayed in larger quantities appear to block mosquitoes’ ability to smell humans.
They suggested that such cloaking compounds may be an alternative to repellents such as DEET, which can have a strong odour and is slightly toxic, leading to some concerns about its safety.
The researchers tested the compounds by putting mosquitoes into a cage divided by a screen, and seeing how the mosquitoes reacted to human odours on the other side of the screen when the different compounds were sprayed there.
The researchers suggested that the presence of some of those cloaking compounds on the skin may explain why mosquitoes are attracted to some people but not others.
The cloaking compounds are similar to chemicals already found in existing drugs and other products, and they appear suitable for use in cosmetics, lotions, clothing and other products that currently incorporate mosquito repellents.
One of the effective compounds was named as 1-methylpiperazine, which is a stimulant drug that has been used as an ingredient in some recreational drugs.
The researchers discovered the compounds based on research done in the lab in the mid to late 1990s that identified 277 compounds present on human skin. Some of them were subsequently found to be very attractive to mosquitoes and are now used for trapping mosquitoes, while others seemed to make it more difficult for mosquitoes to find humans.