April 8, 2003 -- West Nile virus is nothing to fool with -- and this year's mosquito season is approaching fast. But a good insect repellent can literally be a lifesaver. Consumer Reports has sized up the offerings -- from DEET to Skin-So-Soft.
Overall, insect repellents containing DEET and permethrin are the most effective, states the report, which appears on the May issue of the magazine.
West Nile virus swept the U.S. last year and has killed 274 people since first reaching its shores in 1999. The majority of people who are bit by a mosquito carrying West Nile virus will not know they have been infected.
Only about 1% of people develop severe West Nile virus infection -- primarily elderly people and others with weakened immune systems. The latest evidence shows that muscle weakness and a rare, polio-like muscle disorder might be early signs of the potentially deadly West Nile virus.
Products containing DEET -- N,N-diethyl-meta-toluamide -- are the best insect repellents on the market, according to the Consumer Reports' cover story.
In their study for Consumer Reports, three medical entomologists judged insect repellents with a range of DEET concentrations from 7% to 100% -- as well as insect repellents without DEET. They exposed their repellent-treated arms to 200 mosquitoes for 3 minutes, then counted the number of bugs that bit them. If none bit, the testers repeated the test every half-hour until at least one mosquito bit during two successive exposures.
"[DEET] does not kill bugs, but the vapors discourage them from landing or climbing on you," the story states. "Deet is generally acknowledged as the most effective mosquito repellent there is. ... Generally, products with about 30% deet have proven most effective for the longest periods, and they are considered safe for adults and children age 2 months and older."
Of the insect repellents tested, here's how long they fought off mosquitoes:
Off! Deep Woods for Sportsmen
Muskol Ultra 6 Hours
Sawyer Controlled Release
Off! Skintastic with Sunscreen SPF 30
Avon Skin So-Soft Bug Guard/ Sunblock
1 hour (contains no DEET)
Insect repellents using plant oils such as citronella, soybean, coconut, and geranium "provided little if any protection," the report states.
Here's another safe bet: Insect repellents intended for use on clothing -- not on skin -- can provide long-lasting protection when you're wearing long-sleeved shirts, long pants, and socks. Repel Permanone, which contains permethrin, kills bugs on contact, the report states.
In the Consumer Reports' study, the insect repellent Repel Permanone kept all mosquitoes from biting for 24 hours; protection gradually diminished over two weeks. Other insect repellent sprays with the same amount of permethrin should perform similarly in killing mosquitoes, the article states.