Article originally printed on page 21 in the September 13-14, 2003 issue. Reprinted on page 12 in the June 5-6, 2004 issue under title: How Safe Is DEET? Reprinted on page 18 in the August 13-14, 2005 issue under title: DEET Is Your Best Bet for Prevention Reprinted under title: How to Mislead a Mosquito!
on page 14 in the June 10-11, 2006 issue of The Mississauga News under the feature: Health & Wellness, Medical Matters.
With the advent of West Nile Virus has come a new resurgence of interest in mosquito repellents. It has been amusing to watch all of the hype and false information spread about the best way to avoid mosquitoes.
DEET (N,N-diethyl-3-methylbenzamide) is the commonest and most effective agent known to repel insects that feed on humans. It is the active ingredient in most lotions and spray-on repellents. Initially it was developed by the US Army at the end of World War II, after the Pacific campaign became bogged down with troops affected by yellow fever, malaria and dengue. DEET is effective in concentrations as low as 5%.
Mosquitoes and ticks localize their prey with the help of special receptors on their antennae. DEET is thought to scramble this signal. Effectiveness increases with concentration with the maximum effect observed at just above the 50% mark.
Most agents that I see in local stores carry a 5-10% strength, and require re-application every couple of hours. It is important to remember that some of what you put on your skin eventually does trickle into your system.
Blood concentrations of DEET resulting from topical application are rarely significant. There have been reports of seizures occurring when DEET solutions have been ingested intentionally or otherwise.
Insect Repellent Information - Ranking of all popular bug sprays for mosquitoes, flies, bees, wasps, chiggers, gnats, and more, safety ratings based on opinion of BugSpray.com, includes an article About DEET.
