Bugs Turn Their Noses Up at DEET

August 20, 2008 06:58 AM
by Cara McDonough
Mosquitoes hate the way the insect repellant smells. That’s why DEET, which some people avoid because of its harsh chemical nature, works better than anything else.

Something Smells

Previously, scientists believed that DEET blocked mosquitoes’ sense of smell, and therefore the bugs were not drawn to people covered in the repellent. The new research, however, shows that mosquitoes actually find the smell of DEET unpleasant, Reuters reports.

The findings won’t change recommendations for using DEET-based insect repellants; the Centers for Disease Control and Prevention currently recommends DEET as one of the most useful chemicals for avoiding mosquitoes and diseases carried by the insects.

The discovery that neurons on the mosquitoes’ antennae react so strongly to DEET may instead be “incorporated into developing new repellents and maybe in control strategies," said Major Dhillon, president of the American Mosquito Control Association, in a statement.

Related Topics: DEET’s risks and benefits

DEET—the chemical’s technical name is N,N-diethyl-meta-toluamide—was developed by the U.S. Army in 1946 and approved for use by the general public in 1957.

The U.S. Environmental Protection Agency reassessed the chemical in 1998 to ensure its safety and determined, based on toxicity testing, that the chemical does not cause health problems, as long as it is used properly.

Besides protecting people from the discomfort of a mosquito or tick bite, the chemical prevents serious, life threatening illnesses such as Lyme disease and encephalitis. DEET is also a powerful tool in combating the insect-borne disease malaria, which is a major cause of death worldwide, particularly in developing countries, according to MedlinePlus, the U.S. National Library of Medicine’s news service.

Still, some are skeptical about the chemical’s health effects. E/The Environmental Magazine (in a piece reprinted in Scientific American) addressed concerns in June when a reader asked about non-toxic alternatives to the repellent.

The magazine reported that when a study was done in the 1980s, about one-quarter of people using DEET reported negative health effects including headaches, rashes, nausea, dizziness and difficulty concentrating.

There are also those who, for a variety of reasons, would rather go the natural route. Although DEET has proven to be the most effective and longest lasting repellant, there are natural alternatives that work as well.

The CDC recommends two natural products, picaridin and oil of lemon eucalyptus, for repelling insects. Other essential oils, including citronella and peppermint, are also known to work.

Most Recent Beyond The Headlines