“Reports of a French study to examine the effects of DEET on the nervous system of insects has little relevance for the widely-used repellent ingredient’s effects on humans, according to independent scientific experts, including those at the U.S. National Pesticide Information Center,” said Susan Little, director of the DEET Education Program, Washington, D.C.
To suggest that DEET is unsafe when used according to label instructions is irresponsible, she noted, especially since the study in no way reflects the way that consumers use insect repellents that contain it. Experts cited by the BBC and other news organizations agree.
“The experiments that were conducted were mainly done on insects or on individual cells in test tubes, and generally not under conditions that accurately reflect how DEET is used as an insect repellent in the real world,” said Daniel Sudakin, M.D., M.P.H., with the U.S. National Pesticide Information Center, in a BBC News story (http://news.bbc.co.uk/go/pr/fr/-/2/hi/health/8182052.stm). Dr. Sudakin is a widely published medical toxicologist and co-director of Integrative Health Science Facility Core at Oregon State University. “This makes it very difficult if not impossible to interpret the relevance of their findings to humans,” he said.
Dr. Sudakin went on to say: “There have been several recent studies exploring the safety and risks of DEET in humans. The incidence of exposures resulting in neurotoxic effects is very low, when considered in the context of the millions of people around the world who have used insect repellents containing DEET."
Prof. Brian Greenwood of the London School of Hygiene and Tropical Medicine, in the same BBC story, said: “DEET has been used for decades with few reported side effects. And the findings of animal studies do not always match what happens in humans.” Prof. Greenwood, according to the BBC, also said most people tended to use DEET infrequently and, therefore, were exposed to low doses. He said more research may be warranted to investigate the researchers concerns further.
Eric Berger, Houston Chronicle science writer sums up the story in his blog http://blogs.chron.com/sciguy/archives/2009/08/the_deet_alarmism_story_you_didnt_see_in_the_newsp_1.html. He wrote: “The fault lies here with the press office for the journal’s publisher, BioMed Central, for putting out a sensational press release that simply doesn’t seem justified, based on the paper or the wider body of evidence.”
A review of the limited data available on the study reveals that the amount of DEET used was from 200 to 4,000 times greater than would be encountered when using DEET-based insect repellents according to label directions, Little said. “The American Academy of Pediatrics, after reviewing unpublished and published scientific data on DEET, advises that infants as young as two months of age can use a DEET-based repellent in concentrations up to 30 percent,” she said. “That should convey the high level of confidence parents can have in using repellents that contain DEET on their children.”
Other Experts’ Opinions about DEET
Experts have routinely commented on the use of DEET-based repellents, Little said, citing the following:
“Repellents containing DEET are very safe when used according to directions. No serious illness has been linked to use of DEET in children when used according to manufacturer’s recommendations.”
Insect Repellent Use & Safety, www.cdc.gov/ncidod/dvbid/westnile/WNVmyths.htm
“DEET has a remarkable safety profile after 40 years of use and nearly 8 billion human applications. When applied with common sense, DEET-based repellents can be expected to provide a safe as well as long-lasting repellent effect. Despite the substantial attention paid by the lay press every year to the safety of DEET, this repellent has been subjected to more scientific and toxicological scrutiny than any other repellent substance."
Mark S. Fradin, M.D., and Jonathan F. Day, Ph.D., New England Journal of Medicine, 2002
“Part of our confidence in the safety of DEET is based on the extreme rarity of negative effects from its application.”
Daniel Strickman Ph.D., Stephen P. Frances, Ph.D., and Mustapha Debboun, Ph.D., BCE, Prevention of Bug Bites, Stings and Disease, Oxford Press, 2009.
“…DEET has been used for 50 years with a tiny number of reported adverse events, many of which had a history of excessive or inappropriate use of repellent. … Its toxicology has been more closely scrutinized than any other repellent, but it has been deemed safe for human use, including use on children and pregnant women.”
Mustapha Debboun, Ph.D., BCE; Stephen P. Frances, Ph.D., and Daniel Strickman Ph.D. Insect Repellents—Principles, Methods and Uses, CRC Press, 2007.
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