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[ft-l] Mosquito repellent effectiveness study

It SOUNDS like a nice study, but I recall that the mosquitos on Mormon key
in May a couple years back didn't mind eating deet with their dinner (there
were a few more than ten of them I guess).  My 'original bug shirt' was
working pretty well, but they were still munching on my exposed deet covered
hands and feet, so I retreated to my bivy.  Soon they completly covered the
bivy's screen mesh and fully covered the kayak; either they liked the drying
salt, or they were waiting for me to come out.


----- Original Message -----
From: "Kent Wimmer/NONFS/USDAFS" <kwimmer@fs.fed.us>
To: <ft-l@mailman.backcountry.net>
Sent: Thursday, July 25, 2002 1:39 PM
Subject: [ft-l] Mosquito repellent effectiveness study

> FYI - below is a Mosquito repellent effectiveness study
> Kent
> Kent L. Wimmer, AICP
> Florida National Scenic Trail Liaison
> Florida Trail Association, Inc.
> kwimmer@fs.fed.us
> (850) 523-8576 (w)
> (850) 523-8578 (fax)
> (850) 386-8442 (h)
> Mailing address:
> USDA Forest Service
> National Forests in Florida
> 325 John Knox Rd, F-100
> Tallahassee, FL 32303-4160
> ----- Forwarded by Kent Wimmer/NONFS/USDAFS on 07/25/2002 01:38 PM -----
>                     Beatty Gwen
>                     <gfbeatty@yah        To:
>                     oo.com>              cc:
>                                          Subject:     Mosquito repellent
effectiveness study
>                     07/24/2002
>                     07:31 AM
> By Susan Okie
> Washington Post Staff Writer
> Thursday, July 4, 2002; Page A01
> Most insect repellents containing herbal oils are far
> less effective than those containing DEET, a synthetic
> chemical marketed since the 1950s, according to the
> first study to scientifically compare a wide range of
> products.
> Although the botanical repellents have attracted
> chemical-wary consumers, the findings suggest that
> DEET-containing repellents would be the best choice
> for anyone seeking reliable protection from
> mosquito-borne or tick-borne infections such as West
> Nile virus or Lyme disease, said researcher Mark S.
> Fradin, co-author of the study in today's issue of the
> New England Journal of Medicine.
> "If I was traveling to Africa and had to worry about
> getting malaria or . . . yellow fever, I would want a
> DEET-based product on my skin," said Fradin, a
> dermatologist at the University of North Carolina.
> Dozens of insect repellent creams, sprays and lotions
> contain various concentrations of DEET, or
> N,N-diethyl-3-methylbenzamide, which was developed in
> 1946 by the Department of Agriculture for use by the
> military. Other products have active ingredients such
> as citronella, oil of eucalyptus, peppermint oil,
> soybean oil and IR3535, or
> Ethyl-Butylacetylamino-propionate, a biopesticide
> popular in Europe, but new to the United States, that
> is chemically similar to the naturally occurring amino
> acid alanine.
> Scientists are not certain how insect repellents work
> but theorize that they block the sensory receptors
> that mosquitoes and other biting insects use to detect
> carbon dioxide, lactic acid and other chemicals given
> off by their human or animal targets.
> Because no one had compared various repellents'
> effectiveness, Fradin and entomologist Jonathan F. Day
> of the University of Florida decided to test 17
> nationally marketed products under laboratory
> conditions. They asked 15 volunteers at the Florida
> Medical Entomology Laboratory in Vero Beach to stick a
> forearm coated with repellent into a cage containing
> 10 hungry female mosquitoes and see how much time
> elapsed before the first bite.
> Each repellent was tested three times on each subject,
> to ensure that results were consistent and reliable.
> The researchers used Aedes aegypti, a species of
> mosquito that is the carrier of dengue fever and
> yellow fever and that bites readily at any time of
> day. Laboratory mosquitoes were disease-free.
> Volunteers left their arms in the cages for a minute
> at a time, then removed them and repeated the
> procedure at regular intervals, said research
> technician Nazar Hussain, who participated in the
> study. "With some products, you would just put your
> hand in there and they would start coming within five
> seconds," he said.
> Four skin lotions containing DEET in concentrations
> ranging from 5 percent to 24 percent were among the
> top six tested. Off! Deep Woods, a repellent
> containing 23.8 percent DEET, provided the
> longest-lasting protection: 302 minutes, on average.
> The other DEET lotions worked for at least 89 minutes.
> But wristbands, containing DEET or citronella, were
> completely ineffective.
> Two botanical repellents performed as well as some
> DEET-based products. One, containing oil of eucalyptus
> -- Repel Lemon Eucalyptus Lotion Insect Repellent,
> which is also marketed as Fite Bite Plant-Based Insect
> Repellent -- protected participants for an average of
> 120 minutes. Another, containing 2 percent soybean
> oil, Bite Blocker for Kids, worked for an average of
> 95 minutes.
> None of the other repellents tested -- containing
> IR3535, citronella, or oils of peppermint, lemongrass,
> geranium or cedar -- worked for longer than 22
> minutes. Avon Skin-So-Soft Bath Oil, which Fradin said
> he chose to test because of its "mythical status"
> among some consumers, failed after 9.6 minutes, on
> average.
> "The thing that surprised me was the gigantic
> difference between the DEET-based repellents and, for
> the most part, the non-DEET-based repellents," Fradin
> said.
> Consumers have applied DEET more than 8 billion times
> in the past 45 years, and its overall safety record is
> excellent, researchers said. Fradin said there have
> been about 50 cases of significant toxicity, generally
> involving high doses or deliberate ingestion.
> There have been seven reports of seizures in small
> children who were exposed to excessive doses of DEET,
> said Andrew Spielman, a professor of tropical medicine
> at the Harvard School of Public Health who co-wrote a
> commentary on the study. He said repellents containing
> about 35 percent DEET provide mosquito protection
> lasting overnight, and products with higher
> concentrations offered no additional benefit. He
> recommended that less-concentrated DEET products
> should be used for children.
> Spielman noted that Aedes aegypti is somewhat more
> easily repelled than the deer ticks that carry Lyme
> disease or the mosquito species that carry malaria and
> West Nile virus. He added that the many gadgets
> marketed to repel mosquitoes -- including lights,
> coils and devices that produce sound or carbon dioxide
> -- have not been scientifically evaluated.
> Insect repellents are regulated by the Environmental
> Protection Agency. Spielman said product labeling
> typically provides little guidance for users. "It's
> terribly important that there be some way for the
> consumer to understand how much of the material should
> be applied" and how often, he said.
> EPA spokesman Dave Deegan said the agency is revising
> its guidelines for the labeling of repellents, as well
> as requirements on how much proof of effectiveness
> manufacturers must provide.
> "We were really happy to see this study," said Susan
> E. Little of the Consumer Specialty Products
> Association, which represents companies that
> manufacture many of the repellents tested. She
> acknowledged that labeling is frequently vague. She
> said the industry "would be more than happy if the EPA
> came up with a consistent, across-the-board labeling
> procedure for all products, including the botanicals
> and the naturals."
>  2002 The Washington Post Company
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