Mosquitoes stay away from DEET because they hate the smell!

Aug 25 2008

According to scientists in the U.S. the reason why the insect repellent DEET works so well is because mosquitoes don't like the smell.

DEET (Diethyl-meta-toluamide) is the most common active ingredient in insect repellents and is meant to be applied to the skin or to clothing.

It is also used to protect against tick bites which transmit Lyme disease and other tick-borne diseases and mosquitoes which transmit dengue fever, West Nile virus, Eastern Equine Encephalitis and malaria.

DEET was developed by the United States Army during World War II and this latest research lays waste to the theory that DEET works by blocking the insect's ability to detect lactic acid from people, which draws mosquitoes to their victims.

In new study by researchers at University of California Davis, it has been revealed that mosquitoes have a sense of smell located on their antennae and when they smell DEET they avoid it.

Dr. Walter Leal, a professor of entomology at the University of California Davis, says DEET doesn't mask the smell of the host or jam the insect's senses - mosquitoes just don't like it because it smells bad to them and they stay away from it.

For the study Dr. Leal and his team first identified a specific smelling neuron from mosquito antennae that was sensitive to DEET and also tested mosquitoes with "sugar stations" sprayed with and without DEET.

Both male and female mosquitoes eat nectar, but only the females suck blood for food but both stayed away from the DEET areas.

The researchers also found that DEET on human skin suppressed airborne chemicals that would normally be released from the skin which may make skin less attractive to mosquitoes.

Lead author Dr. Zainulabeuddin Syed, says discovering the precise antennae neurons that detect the chemical cocktail known as DEET was a breakthrough.

The researchers say DEET is "the gold standard" of mosquito repellents and is used by more than 200 million people around the world to keep mosquitoes at bay.

The hope their research will lead to better disease prevention, as mosquitoes are responsible for spreading diseases like Dengue Fever, West Nile virus, St. Louis encephalitis and malaria.

The study was published in the Aug. 18-22 issue of the journal Proceedings of the National Academy of Sciences.