Difference between revisions of "DEET" - New World Encyclopedia

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'''DEET''' is a chemical, '''''N'',''N''-Diethyl-''m''-toluamide''', that acts as an [[insect repellent]] to prevent bites from [[mosquito]]es, [[flea]]s, biting [[fly|flies]], and other [[insect]]s, as well as [[tick]]s ([[arachnid]]s). It is the most common active [[ingredient]] in insect repellents, popular in liquid sprays, lotions, and sticks, and is intended to be applied to the [[skin]] or to [[clothing]].
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'''DEET''' is a chemical, '''''N,'' ''N''-Diethyl-''m''-toluamide,''' that acts as an [[insect repellent]] to prevent bites from [[mosquito]]es, [[flea]]s, biting [[fly|flies]], and other [[insect]]s, as well as [[tick]]s ([[arachnid]]s). It is the most common active [[ingredient]] in insect repellents, popular in liquid sprays, lotions, and sticks, and is intended to be applied to the [[skin]] or to [[clothing]]. It is estimated that every year roughly thirty percent of the United States population uses various products that contain DEET (NPIC 2008).
  
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In addition to being a nuisance, the bites of a number of insects and ticks pose health risks. For example, ticks bites may transmit [[Lyme disease]], several [[rickettsiosis|rickettsioses]], [[tick-borne meningoencephalitis]], and other [[tick-borne disease]]s), and [[mosquito]] bites may transmit [[malaria]], [[dengue fever]], [[West Nile virus]], and [[eastern equine encephalitis]]. Therefore, the use of an insect repellent is an important measure for prevention of these vector-borne [[disease]]s. DEET is one of the most effective insect repellents known, and is considered safe when used properly, although the American Academy of Pediatrics recommends not using on infants less than two months old (CDC 2008).  
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In addition to being a nuisance, the bites of a number of insects and ticks pose health risks. For example, ticks bites may transmit [[Lyme disease]], several [[rickettsiosis|rickettsioses]], [[tick-borne meningoencephalitis]], and other [[tick-borne disease]]s, and [[mosquito]] bites may transmit [[malaria]], [[dengue fever]], [[West Nile virus]], and [[eastern equine encephalitis]]. Therefore, the use of an insect repellent is an important measure for prevention of these vector-borne [[disease]]s. DEET is one of the most effective insect repellents known, and is considered safe for humans and the environment when used properly, although the American Academy of Pediatrics recommends not using on infants less than two months old (CDC 2008).  
  
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==Overview and description==
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==Overview, description and method of action==
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Deet is a slightly yellow, almost colorless liquid at [[room temperature]]. Its [[IUPAC]] name is ''N,N''-Diethyl-3-methylbenzamide and it also is known as ''N,N''-Diethyl-''m''-toluamide. It can be prepared from [[M-toluic acid|''m''-methylbenzoic acid]] and [[diethylamine]]. This can be achieved by preparing the [[acid chloride]] and subsequently reacting that with the [[diethylamine]]. It can be distilled under [[vacuum]]: boiling point 111°C at 1 [[mm Hg]]. The chemical formula of DEET is C<sub>12</sub>H<sub>17</sub>NO.
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Deet is a slightly yellow, almost colorless liquid at [[room temperature]]. Its [[IUPAC]] name is ''N,N''-Diethyl-3-methylbenzamide and it also is known as ''N,N''-Diethyl-''m''-toluamide. It can be prepared from [[M-toluic acid|''m''-methylbenzoic acid]] and [[diethylamine]]. This can be achieved by preparing the [[acid chloride]] and subsequently reacting that with the diethylamine. It can be distilled under [[vacuum]]: boiling point 111°C at 1 [[mm Hg]]. DEET has a faint odor and does not easily dissolve in water (NPIC 2008). DEET is an effective [[solvent]] (Petherick 2008), and may dissolve (part of) some [[plastics]], [[rayon]], [[spandex]], other [[synthetic fiber|synthetic fabrics]], [[leather]], and painted or [[varnish]]ed surfaces. The chemical formula of DEET is C<sub>12</sub>H<sub>17</sub>NO.
  
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DEET was developed by the [[United States Army]] for protection of soldiers, following its experience of [[jungle warfare]] during [[World War II]]. It entered military use in 1946 and civilian use in 1957. Originally tested as a pesticide on farm fields, the United States Government applied it for war time usage, particularly when in Vietnam and around that region of Asia.
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DEET was developed by the [[United States Army]] for protection of soldiers in insect-infested areas, following its experience of [[jungle warfare]] during [[World War II]]. It entered military use in 1946 and civilian use in 1957. Originally tested as a pesticide on farm fields, the United States Government applied it for war time usage, particularly when in Vietnam and around that region of Asia.
  
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==Mechanism of action==
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The mechanism of how DEET works is not completely understood for all insects (NPIC 2008). In general, DEET is believed to work by blocking insect [[olfactory receptor]]s for [[1-octen-3-ol]], a [[volatile]] substance that is contained in human [[sweat]] and [[breath]]. DEET effectively "blinds" the insect's senses so that the biting/feeding [[instinct]] is not triggered by humans or animals that produce these chemicals. DEET does not appear to affect the insect's ability to smell [[carbon dioxide]], as had been suspected earlier (Petherick 2008; Ditzen et al. 2008).
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The mechanism of how DEET works is not completely understood for all insects (NPIC 2008).  
 
  
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In general, DEET is believed to work by blocking insect [[olfactory receptor]]s for [[1-octen-3-ol]], a [[volatile]] substance that is contained in human [[sweat]] and [[breath]]. DEET effectively "blinds" the insect's senses so that the biting/feeding [[instinct]] is not triggered by humans or animals which produce these chemicals. DEET does not appear to affect the insect's ability to smell [[carbon dioxide]], as had been suspected earlier (Petherick 2008; Ditzen et al. 2008).
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==Use of DEET as an insect repellent==
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[[Image:DEET products.jpg|thumb|right|200px|DEET is available in many insect repellents]]
  
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DEET is used in a wide variety of products, including liquid sprays, lotions, and sticks. The concentration can vary considerably, such as 4.75 percent, 20 percent, 23.8 percent, up to 100 percent. Various studies have found a direct [[correlation]] between DEET concentration and hours of protection against insect bites. Fradin and Day (2002) found that a product with 23.8 percent DEET provided an average of five hours of protection against insect bites, compared to four hours of protection offered by a product with 20 percent DEET, while a 6.65 percent DEET product provided almost two hours of protection, and a product with 4.75 percent DEET provided roughly 1.5 hours of protection. Matsuda et al. (1996) found a 100 percent DEET solution offered up to 12 hours of protection, while several lower concentration DEET formulations (20-34 percent) offered three to six hours of protection. Other research has corroborated the effectiveness of DEET (Williamson 2002).
  
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==Concentrations==
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==Effects on health==
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[[Image:DEET products.jpg|thumb|right|200px|DEET is available in many insect repellents]]
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One can be exposed to DEET through contact with the skin or eyes, inhalation, or swallowing. For example, one may inhale the spray if used in indoor spaces where vapors remain and may swallow DEET if the hands are not washed after applying (NPIC 2008). If DEET gets into the eyes, one can experience pain, irritation, and watery eyes, and extended exposure to the skin can result in redness, a rash, irritation, and swelling (NPIC 2008). Swallowing DEET can result in upset [[stomach]], vomiting, and nausea (NPIC 2008).
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DEET is often sold and used in concentrations up to 100%. ''[[Consumer Reports]]'' found a direct [[correlation]] between DEET concentration and hours of protection against insect bites. 100% DEET was found to offer up to 12 hours of protection while several lower concentration DEET formulations (20%-34%) offered 3-6 hours of protection.<ref name = matsuda>{{cite journal | title = Essential oil analysis and field evaluation of the citrosa plant "Pelargonium citrosum" as a repellent against populations of Aedes mosquitoes | author = Matsuda, Brent M.; Surgeoner, Gordon A.; Heal, James D.; Tucker, Arthur O.; Maciarello, Michael J. | journal = Journal of the American Mosquito Control Association | year = 1996 | volume = 12 | issue = 1 | pages = 69–74}}</ref> Other research has corroborated the effectiveness of DEET.<ref name="Independent study: DEET products superior for fending off mosquito bites">{{cite press release | publisher = [[University of North Carolina at Chapel Hill|University of North Carolina]] | title = Independent study: DEET products superior for fending off mosquito bites | author = David Williamson | date = [[3 July]] [[2002]] | url = http://www.unc.edu/news/archives/jul02/fradin070202.htm}}</ref> The Center for Disease Control recommends 30-50% DEET to prevent the spread of pathogens carried by insects.{{Fact|date=June 2008}}
 
  
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==Effects on health==
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As a precaution, manufacturers advise that DEET products should not be used under clothing or on damaged skin, and that preparations be washed off after they are no longer needed or between applications (CDC 2008).
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As a precaution, manufacturers advise that DEET products should not be used under clothing or on damaged skin, and that preparations be washed off after they are no longer needed or between applications.<ref name="CDC">{{cite web | url = http://www.cdc.gov/ncidod/dvbid/westnile/qa/insect_repellent.htm | title = Insect Repellent Use and Safety | work = West Nile Virus | publisher = [[Centers for Disease Control and Prevention]] | date =  2007-01-12}}</ref> DEET can act as an irritant;<ref name=petherick/>
 
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in rare cases, it may cause skin reactions.<ref name="CDC"/>
 
  
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In the DEET Reregistration Eligibility Decision (RED), the [[EPA]] reported 14 to 46 cases of potential DEET-associated [[seizure]]s, including 4 deaths. The EPA states: ''" ..it does appear that some cases are likely related to DEET [[toxicity]],"'' but observed that with 30% of the US population using DEET, the likely seizure rate is only about one per 100 million users.<ref>[http://www.epa.gov/oppsrrd1/REDs/0002red.pdf "Reregistration Eligibility Decision: DEET." U.S. Environmental Protection Agency, Office of Prevention, Pesticides, and Toxic Substances. September 1998. pp39-40]</ref>
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In the DEET Reregistration Eligibility Decision (RED), the [[EPA]] reported 14 to 46 cases of potential DEET-associated [[seizure]]s, including 4 deaths. The EPA states: "…It does appear that some cases are likely related to DEET [[toxicity]]," but observed that with thirty percent of the U.S. population using DEET, the likely seizure rate is only about one per 100 million users (EPA 1998). There has been a report that "[[Everglades National Park]] employees having extensive DEET exposure were more likely to have insomnia, mood disturbances, and impaired cognitive function than were lesser exposed co-workers" (EXTOXNET 1997).  
  
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The Pesticide Information Project of Cooperative Extension Offices of [[Cornell University]] states that ''"[[Everglades National Park]] employees having extensive Deet exposure were more likely to have insomnia, mood disturbances and impaired cognitive function than were lesser exposed co-workers".'' <ref name="EXTOXNET">{{cite web | publisher = EXTOXNET | work = Pesticide Information Profile | title = DEET | date = October 1997 | url = http://pmep.cce.cornell.edu/profiles/extoxnet/carbaryl-dicrotophos/deet-ext.html | accessdate = 2007-09-26}}</ref>
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The American Academy of Pediatrics (AAP) states that a concentration of 10 percent appears to be as safe for children as products with a 30 percent concentration, although they do not recommend use of repellents with DEET for infants less than two months old (CDC 2008). They further recommend that DEET be applied no more than one time a day for children older than two months and that the lowest concentrations of DEET available be used (NPIC 2008). It is generally not advised to apply on the hands of children, nor near the mouth or eyes. Note that these are recommendations for children not considered to be at risk of serious vector-borne diseases.
  
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The [[American Academy of Pediatrics]] found no difference in safety for children, between products containing 10% and 30% DEET, when used as directed, but recommends that DEET not be used on infants less than two months old.<ref name="CDC"/>
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Studies have shown that a small amount of the DEET applied to skin is taken into the body, and that this intake is greater if DEET and alcohol both are applied to the skin. The DEET taken into the body remains in the [[blood]] for up to 12 hours. However, all of the DEET is broken down by the [[liver]] into smaller chemicals and eliminated from the body, largely through the urine, with nearly all of the DEET eliminated from the body within 24 hours of application (NPIC 2008).  
  
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==Effects on materials==
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Evidence has not been found that DEET causes [[cancer]] in humans or animals, and it has been classified by the U.S. Environmental Protection Agency as "Not Classifiable as a Human Carcinogen," meaning there is not enough evidence that it does or does not cause cancer (NPIC 2008).
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DEET is an effective [[solvent]],<ref name=petherick/> and may dissolve (part of) some [[plastics]], [[rayon]], [[spandex]], other [[synthetic fiber|synthetic fabrics]], [[leather]], and painted or [[varnish]]ed surfaces.
 
  
 
==Effects on the environment==
 
==Effects on the environment==
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Although few studies have been conducted to assess possible effects on the environment, DEET is a moderate chemical [[pesticide]] and may not be suitable for use in and around water sources.{{Fact|date=June 2008}} Though DEET is not expected to [[bioaccumulation|bioaccumulate]], it has been found to have a slight toxicity for coldwater [[fish]] such as the [[rainbow trout]]<ref>U.S. Environmental Protection Agency. 1980. Office of Pesticides and Toxic Substances. N,N-diethyl-m-toluamide (Deet) Pesticide Registration Standard. December, 1980. 83 pp.</ref> and the [[tilapia]] <ref>{{cite journal | author = Mathai, AT; Pillai, KS; Deshmukh, PB | year = 1989 | title = Acute toxicity of deet to a freshwater fish, Tilapia mossambica : Effect on tissue glutathione levels | journal = [[Journal of Environmental Biology]] | volume = 10 | issue = 2 | pages  = 87–91. | url = http://md1.csa.com/partners/viewrecord.php?requester=gs&collection=ENV&recid=2427671&q=DEET+fish+-permethrin&uid=791055180&setcookie=yes }}</ref>, and it has also been shown to be toxic for some species of freshwater [[zooplankton]].<ref>{{cite journal | author = J. Seo, Y. G. Lee, S. D. Kim, C. J. Cha, J. H. Ahn and H. G. Hur | title = Biodegradation of the Insecticide N,N-Diethyl-m-Toluamide by Fungi: Identification and Toxicity of Metabolites | year = 2005 | journal = [[Archives of Environmental Contamination and Toxicology]] | volume = 48 | issue = 3 | pages = 323–328 | doi = 10.1007/s00244-004-0029-9}}</ref> DEET has been detected in significant levels in waterbodies as a result of production and use, such as in the [[Mississippi River]] and its tributaries, where a 1991 study detected levels varying from 5 to 201 [[nanogram|ng]]/L. <ref>{{cite web| title = Errol Zeiger, Raymond Tice, Brigette Brevard, (1999) N,N-Diethyl-m-toluamide (DEET) <nowiki>[134-62-3]</nowiki> - Review of Toxicological Literature | url = http://ntp.niehs.nih.gov/ntp/htdocs/Chem_Background/ExSumPdf/DEET.pdf | accessdate = July 20|format=PDF}}</ref>
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Although few studies have been conducted to assess possible effects on the environment, DEET is a moderate chemical [[pesticide]] and may not be suitable for use in and around water sources. Because it is so commonly used, it has been found in wastewater and other bodies of water impacted by wastewater. DEET has been detected in significant levels in waterbodies as a result of production and use, such as in the [[Mississippi River]] and its tributaries, where a 1991 study detected levels varying from 5 to 201 [[nanogram|ng]]/L (Zeiger et al. 1999).  
  
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==Alternatives==
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In the [[soil]], it can be broken down by [[fungi]], [[bacteria]], and other microorganisms, and experiments have shown that fungal and bacterial breakdown products were less toxic than DEET itself (NPIC 2008). Likewise, as a mist or vapor in the air, it breaks down as well (NPIC 2008).  
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Studies have shown [[eucalyptus]]-based repellents which contain the natural oil [[eucalyptol]] to be a highly effective and nontoxic alternative to DEET.<ref>{{cite news |first= |last= |authorlink= |coauthors= |title=The Claim: Listerine Can Ward Off a Swarm of Mosquitoes |url=http://www.nytimes.com/2008/06/24/health/24real.html?ex=1372046400&en=5fae59840001d0c7&ei=5124&partner=permalink&exprod=permalink |quote=Several studies, including one by the London School of Hygiene and Tropical Medicine, have found that eucalyptus-based repellents can be extremely effective, and nontoxic to humans.}}</ref>
 
  
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[[Icaridin]] is another insect repellent of strength comparable to DEET, but it is less irritating and doesn't dissolve plastics.{{Fact|date=June 2008}}
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DEET has been found to have a slight toxicity for coldwater [[fish]] such as the [[rainbow trout]] (EPA 1980) and the [[tilapia]] (Mathai et al. 1989), and it has also been shown to be toxic for some species of freshwater [[zooplankton]] (Seo et al. 2005). In very high concentration, about 75,000 times greater than the highest concentrations found in streams or wastewater, DEET was extremely toxic to freshwater fish and insects, killing half of the fish and insects (NPIC 2008). DEET is not expected to [[bioaccumulation|bioaccumulate]].
  
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A test of various marketed insect repellents by an independent consumer organization found that synthetic repellents, including DEET, were more effective than repellents with ‘natural’ active ingredients. All the synthetics gave almost 100% repellency for the first 2 hours, whereas the natural repellent products tested were most effective for the first 30-60 minutes and then required reapplication to be effective over several hours.<ref>{{cite web | title = Test: Mosquito repellents | publisher = CHOICE | url = http://www.choice.com.au/viewArticle.aspx?id=105015&catId=100281&tid=100008&p=5&title=Test%3a+Mosquito+repellents | date = December 2005 | accessdate = 2007-09-26}}</ref>
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==Alternatives==
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Picaridin (KBR 3023) is another repellent recommended by the [[Centers for Disease Control and Prevention]] (CDC); permethrin is recommended for use on clothing, shoes, bed nets, and camping gear, but not directly to the [[skin]] (CDC 2008).
  
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[[Citronella oil]] has been used as an insect repellent for 60 years.<ref>{{cite web | publisher = [[U.S. Environmental Protection Agency]] | title =  Citronella (Oil of Citronella) (021901) Fact Sheet | date = November 1999 | url = http://www.epa.gov/pesticides/biopesticides/ingredients/factsheets/factsheet_021901.htm | accessdate=July 20 | accessyear=2007}}</ref>  Its mosquito repellency qualities have been verified by research,<ref>{{cite journal | author = Jeong-Kyu KIM, Chang-Soo KANG, Jong-Kwon LEE, Young-Ran KIM, Hye-Yun HAN, Hwa Kyung YUN | title = Evaluation of Repellency Effect of Two Natural Aroma Mosquito Repellent Compounds, Citronella and Citronellal | journal = [[Entomological Research]] | volume = 35 | issue = 2 | pages = 117–120 | year = 2005 | doi = 10.1111/j.1748-5967.2005.tb00146.x}}</ref> <ref>Ibrahim Jantan, and Zaridah Mohd. Zaki, ''Development of environment-friendly insect repellents from the leaf oils of selected Malaysian plants'', ASEAN Review of Biodiversity and Environmental Conservation (ARBEC), May 1998.</ref><ref>{{cite journal | author = Trongtokit Y, Rongsriyan Y, Komalamisra N, Apiwathnasom L | title = Comparative repellency of 38 essential oils against mosquito bites | journal = [[Phytother Res.]] | year = 2005 | volume = 19 | issue = 4 | pages = 303–9 | doi = 10.1002/ptr.1637}}</ref> however, the repellency duration of DEET is much greater.<ref name="N Engl Journ Med"/>
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Studies have shown [[eucalyptus]]-based repellents that contain the natural oil [[eucalyptol]] to be a highly effective and nontoxic alternative to DEET (O'Conner 2008). Oil of lemon eucalyptus was found to offer similar protection as repellents with low concentrations of DEET (CDC 2008).  
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While most [[essential oil]] based repellents are not as effective as DEET,<ref name="N Engl Journ Med">{{cite journal | author = M. S. Fradin and J. F. Day | title = Comparative Efficacy of Insect Repellents against Mosquito Bites | year = 2002 | journal = [[N Engl J Med]] | volume = 347 | issue = 1 | pages = 13–18 | doi = 10.1056/NEJMoa011699 | pmid = 12097535}}</ref><ref>{{cite journal | author = Collins, D.A. | coauthors = Brady, J.N.; Curtis, C.F. | year = 1993 | title = Assessment of the efficacy of Quwenling as a Mosquito repellent | journal = [[Phytotherapy Research]] | volume = 7 | issue = 1 | pages = 17–20 | doi = 10.1002/ptr.2650070106}}</ref> research also shows that some [[essential oil]] based formulas can be comparable to DEET, and somewhat better specifically as mosquito repellant. <ref>{{cite journal | author = Trongtokit Y. | coauthors = Rongsriyam Y, Komalamisra N, Krisadaphong P, Apiwathnasorn C, Krisadaphong P, Apiwathasorn C, | year = 2004 | title = ''Laboratory and field trial of developing medicinal local Thai plant products against four species of mosquito vectors'' | journal = [[Southeast Asia J, Trop Med Public Health]] | volume = 35 | issue = 2 | pages = 325–33 | pmid = 15691131}}</ref>
 
  
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Research suggests that distilled [[nepetalactone]], the active ingredient in [[catnip]], repels mosquitoes ten times more effectively than DEET,<ref>{{cite web | url=http://www.chemistry.org/portal/a/c/s/1/feature_ent.html?id=4acf6768ce1b11d5f2944fd8fe800100 | title=Mosquito Repellents | author=Dennis Loney | publisher=[[American Chemical Society]] | date=[[2001-08-28]] | accessdate=2007-08-28}}</ref> but that it is not as effective a repellent on skin.<ref>{{cite journal | author = Chauhan, K.R. | coauthors = Klun, J.A.; Debboun, M.; Kramer, M. | year = 2005 | title = Feeding Deterrent Effects of Catnip Oil Components Compared with Two Synthetic Amides Against Aedes aegypti | journal = [[Journal of Medical Entomology]] | volume = 42 | issue = 4 | pages = 643–646 | doi = 10.1603/0022-2585(2005)042&#91;0643:FDEOCO&#93;2.0.CO;2 | doi_brokendate = 2008-06-24}}</ref>
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[[Citronella oil]] has been used as an insect repellent for 60 years (EPA 1999). Its mosquito repellent qualities have been verified by research (Jeong-Kyu 2005; Jantan and Zaki 1998; Trongtokit et al. 2005); however, the repellency duration of DEET is much greater (Fradin and Day 2002).
  
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==See also==
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A test of various marketed insect repellents by an independent consumer organization found that synthetic repellents (DEET and picaridin) were more effective than repellents with "natural" active ingredients. All the synthetics gave almost 100 percent repellency for the first 2 hours, whereas the natural repellent products tested were most effective for the first 30-60 minutes and then required reapplication to be effective over several hours (Choice 2005). Likewise, the CDC suggests the repellents with DEET or picaridin provide longer-lasting protection than other products, while oil of lemon eucalyptus provides longer-lasting protection than other plant-based repellents (CDC 2008). While most [[essential oil]] based repellents are not as effective as DEET (Fradin and Day 2002; Collins et al. 1993), some research also suggests that some essential oil based formulas are comparable to DEET, and somewhat better specifically as mosquito repellant (Trongtokit et al. 2004).
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* [[Icaridin]]
 
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* [[Permethrin]], a [[pyrethroid]]
 
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* [[Citronella oil]]
 
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* [[Beautyberry]]
 
  
 
== References ==
 
== References ==
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{{refbegin}}
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* Centers for Disease Control and Prevention (CDC). 2008. [http://www.cdc.gov/ncidod/dvbid/westnile/qa/insect_repellent.htm West Nile virus: Questions and answers.] ''Centers for Disease Control and Prevention, Division of Vector-borne Infectious Diseases''. Retrieved August 4, 2008.
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*{{cite journal | author = M. S. Fradin | title = Mosquitoes and Mosquito Repellents: A Clinician's Guide | year = 1998 | journal = Ann Intern Med | volume = 128 | issue = 11 | pages = 931–940 | url = http://www.annals.org/cgi/content/abstract/128/11/931 | pmid = 9634433}}
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* Chauhan, K.R., J.A. Klun, M. Debboun, and M. Kramer. 2005. Feeding deterrent effects of catnip oil components compared with two synthetic amides against ''Aedes aegypti''. ''Journal of Medical Entomology'' 42(4): 643–646.
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{{refend}}
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* Choice. 2005. [http://www.choice.com.au/viewArticle.aspx?id=105015&catId=100281&tid=100008&p=5&title=Test%3a+Mosquito+repellents Test: Mosquito repellents.] ''CHOICE'' December 2005. Retrieved August 4, 2008.
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{{reflist}}
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* Collins, D.A., J.N. Brady, and C.F. Curtis. 1993. [http://www3.interscience.wiley.com/journal/112262407/abstract Assessment of the efficacy of Quwenling as a mosquito repellent.] ''Phytotherapy Research'' 7(1): 17–20. Retrieved August 4, 2008.
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* Ditzen, M., M. Pellegrino, and L.B. Vosshall. 2008. [http://www.ncbi.nlm.nih.gov/pubmed/18339904 Insect odorant receptors are molecular targets of the insect repellent DEET.] ''Science'' 319(5871):1838-42. Retrieved August 4, 2008.
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* National Pesticide Information Center (NPIC). 2008. [http://npic.orst.edu/factsheets/DEETgen.pdf DEET General FAQ Sheet]. ''National Pesticide Information Center''. Retrieved August 4, 2008.
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* Environmental Protection Agency (EPA), United States. 1980. N,N-diethyl-m-toluamide (DEET) Pesticide Registration Standard. ''U.S. Environmental Protection Agency, Office of Pesticides and Toxic Substances''.
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* Environmental Protection Agency (EPA), United States. 1998. [http://www.epa.gov/oppsrrd1/REDs/0002red.pdf Reregistration Eligibility Decision (RED): DEET.] ''U.S. Environmental Protection Agency, Office of Prevention, Pesticides, and Toxic Substances''.
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* Centers for Disease Control and Prevention (CDC). 2008. [http://www.cdc.gov/ncidod/dvbid/westnile/qa/insect_repellent.htm West Nile virus: Questions and answers]. ''Centers for Disease Control and Prevention, Division of vector-borne infectious diseases''. Retrieved August 4, 2008.
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* Environmental Protection Agency (EPA), United States. 1999. [http://www.epa.gov/pesticides/biopesticides/ingredients/factsheets/factsheet_021901.htm Citronella (oil of citronella) (021901) fact sheet.] ''U.S. Environmental Protection Agency''. Retrieved August 4, 2008.  
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* Extension Toxicology Network (EXTOXNET). 1007. [http://pmep.cce.cornell.edu/profiles/extoxnet/carbaryl-dicrotophos/deet-ext.html DEET.] ''EXTOXNET''. Retrieved August 4, 2008.
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; .<ref name=petherick>{{Cite web
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* Fradin, M.S. 1998. [http://www.annals.org/cgi/content/abstract/128/11/931 Mosquitoes and mosquito repellents: A clinician's guide.] ''Ann Intern Med'' 128(11): 931–940. Retrieved August 4, 2008.
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| last = Anna Petherick
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* Fradin, M.S., and J. F. Day. 2002. [http://content.nejm.org/cgi/content/full/347/1/13 Comparative efficacy of insect repellents against mosquito bites.] ''New England Journal of Medicine'' 347(1):13-18. Retrieved August 4, 2008.  
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| title = How DEET jams insects' smell sensors
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* Jantan, I., and Z.M. Zaki. 1998. Development of environment-friendly insect repellents from the leaf oils of selected Malaysian plants. ''ASEAN Review of Biodiversity and Environmental Conservation (ARBEC)'' May 1998.
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| accessdate = 2008-03-16
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* Kim, J.-K., C.-S. Kang, J.-K. Lee, Y.-R. Kim, H.-Y. Han, and H. K. Yun. 2005. [http://www3.interscience.wiley.com/journal/118676220/abstract?CRETRY=1&SRETRY=0 Evaluation of repellency effect of two natural aroma mosquito repellent compounds, citronella and citronellal.] ''Entomological Research'' 35(2): 117–120. Retrieved August 4, 2008.
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| work = Nature News
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* Mathai, A.T., K.S. Pillai, and P.B. Deshmukh. 1989. [http://md1.csa.com/partners/viewrecord.php?requester=gs&collection=ENV&recid=2427671&q=DEET+fish+-permethrin&uid=791055180&setcookie=yes Acute toxicity of deet to a freshwater fish, ''Tilapia mossambica:'' Effect on tissue glutathione levels.] ''Journal of Environmental Biology'' 10(2): 87–91. Retrieved August 4, 2008.
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| date = 2008-03-13
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* Matsuda, B.M., G.A. Surgeoner, J.D. Heal, A.O. Tucker, and M.J. Maciarello. 1996. Essential oil analysis and field evaluation of the citrosa plant "Pelargonium citrosum" as a repellent against populations of ''Aedes'' mosquitoes. ''Journal of the American Mosquito Control Association'' 12(1): 69–74.
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| url = http://www.nature.com/news/2008/080313/full/news.2008.672.html
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* National Pesticide Information Center (NPIC). 2008. [http://npic.orst.edu/factsheets/DEETgen.pdf DEET general FAQ sheet.] ''National Pesticide Information Center''. Retrieved August 4, 2008.
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}}</ref><ref>
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* O'Conner, A. 2008. [http://www.nytimes.com/2008/06/24/health/24real.html?ex=1372046400&en=5fae59840001d0c7&ei=5124&partner=permalink&exprod=permalink The claim: Listerine can ward off a swarm of mosquitoes.] ''New York Times'' June 24, 2008.
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{{cite journal
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* Petherick, A. 2008. [http://www.nature.com/news/2008/080313/full/news.2008.672.html How DEET jams insects' smell sensors.] ''Nature News'' March 13, 2008. Retrieved August 4, 2008.
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| author = Mathias Ditzen, Maurizio Pellegrino, Leslie B. Vosshall
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* Seo, J., Y.G. Lee, S.D. Kim, C.J. Cha, J.H. Ahn, and H.G. Hur. 2005. [http://www.springerlink.com/content/h7j51110835263pr/ Biodegradation of the insecticide N,N-Diethyl-m-Toluamide by fungi: Identification and toxicity of metabolites,] ''Archives of Environmental Contamination and Toxicology'' 48(3): 323–328. Retrieved August 4, 2008.
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| year = 2008
+
* Trongtokit, Y., Y. Rongsriyan, N. Komalamisra, and L. Apiwathnasom. 2005. [http://www3.interscience.wiley.com/journal/110573462/abstract Comparative repellency of 38 essential oils against mosquito bites.] ''Phytother Res. 19(4): 303–9.
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| title = Insect Odorant Receptors Are Molecular Targets of the Insect Repellent DEET
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* Trongtokit, Y., Y. Rongsriyam, N. Komalamisra, P. Krisadaphong, C. Apiwathnasorn, P. Krisadaphong, and C. Apiwathasorn. 2004. [http://www.ncbi.nlm.nih.gov/pubmed/15691131 Laboratory and field trial of developing medicinal local Thai plant products against four species of mosquito vectors.] ''Southeast Asia J, Trop Med Public Health'' 35(2): 325–33. Retrieved August 4, 2008.
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| journal = Sciencexpress
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* Williamson, D. 2002. Independent study: DEET products superior for fending off mosquito bites. ''UNC News Services'' July 3, 2002 (No. 378).
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| volume =319
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* Zeiger, E., R. Tice, and B. Brevard. 1999. [http://ntp.niehs.nih.gov/ntp/htdocs/Chem_Background/ExSumPdf/DEET.pdf N,N-Diethyl-m-toluamide (DEET): Review of toxicological literature.] ''Integrated Laboratory Systems''. Retrieved August 4, 2008.
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| issue =
 
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| pages = 1838
 
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| pmid =18339904
 
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| doi = 10.1126/science.1153121
 
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| url =}}</ref>
 
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== External links ==
 
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* [http://npic.orst.edu/wnv/ West Nile Virus Resource Guide - National Pesticide Information Center]
 
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* [http://www.health.state.ny.us/nysdoh/westnile/education/2737.htm Health Advisory: Tick and Insect Repellents, New York State]
 
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* [http://www.cdc.gov/ncidod/dvbid/westnile/qa/insect_repellent.htm US Centers for Disease Control information on DEET]
 
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* [http://www.epa.gov/pesticides/factsheets/chemicals/deet.htm US Environmental Protection Agency information on DEET]
 
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* [http://www.gulflink.osd.mil/library/randrep/pesticides_paper/mr1018.8.ch5.html Review of scientific literature on DEET] (from a [[RAND Corporation]] report on [[Gulf War]] illnesses)
 
  
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[[Category:Life sciences]]
 
[[Category:Life sciences]]
 
[[Category:Biochemistry]]
 
[[Category:Biochemistry]]
  
 
{{credit|DEET|228926212}}
 
{{credit|DEET|228926212}}

Latest revision as of 08:37, 15 January 2023


DEET
DEET2.png
IUPAC name N,N-Diethyl-3-methylbenzamide
Other names N,N-Diethyl-m-toluamide
Identifiers
CAS number [134-62-3]
SMILES CCN(CC)C(=O)C1=CC(=CC=C1)C
Properties
Molecular formula C12H17NO
Molar mass 191.27 g/mol
Density 0.998 g/mL
Melting point

-45 °C

Boiling point

288-292 °C

Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)

DEET is a chemical, N, N-Diethyl-m-toluamide, that acts as an insect repellent to prevent bites from mosquitoes, fleas, biting flies, and other insects, as well as ticks (arachnids). It is the most common active ingredient in insect repellents, popular in liquid sprays, lotions, and sticks, and is intended to be applied to the skin or to clothing. It is estimated that every year roughly thirty percent of the United States population uses various products that contain DEET (NPIC 2008).

In addition to being a nuisance, the bites of a number of insects and ticks pose health risks. For example, ticks bites may transmit Lyme disease, several rickettsioses, tick-borne meningoencephalitis, and other tick-borne diseases, and mosquito bites may transmit malaria, dengue fever, West Nile virus, and eastern equine encephalitis. Therefore, the use of an insect repellent is an important measure for prevention of these vector-borne diseases. DEET is one of the most effective insect repellents known, and is considered safe for humans and the environment when used properly, although the American Academy of Pediatrics recommends not using on infants less than two months old (CDC 2008).

Overview, description and method of action

Deet is a slightly yellow, almost colorless liquid at room temperature. Its IUPAC name is N,N-Diethyl-3-methylbenzamide and it also is known as N,N-Diethyl-m-toluamide. It can be prepared from m-methylbenzoic acid and diethylamine. This can be achieved by preparing the acid chloride and subsequently reacting that with the diethylamine. It can be distilled under vacuum: boiling point 111°C at 1 mm Hg. DEET has a faint odor and does not easily dissolve in water (NPIC 2008). DEET is an effective solvent (Petherick 2008), and may dissolve (part of) some plastics, rayon, spandex, other synthetic fabrics, leather, and painted or varnished surfaces. The chemical formula of DEET is C12H17NO.

DEET was developed by the United States Army for protection of soldiers in insect-infested areas, following its experience of jungle warfare during World War II. It entered military use in 1946 and civilian use in 1957. Originally tested as a pesticide on farm fields, the United States Government applied it for war time usage, particularly when in Vietnam and around that region of Asia.

The mechanism of how DEET works is not completely understood for all insects (NPIC 2008). In general, DEET is believed to work by blocking insect olfactory receptors for 1-octen-3-ol, a volatile substance that is contained in human sweat and breath. DEET effectively "blinds" the insect's senses so that the biting/feeding instinct is not triggered by humans or animals that produce these chemicals. DEET does not appear to affect the insect's ability to smell carbon dioxide, as had been suspected earlier (Petherick 2008; Ditzen et al. 2008).

Use of DEET as an insect repellent

DEET is available in many insect repellents

DEET is used in a wide variety of products, including liquid sprays, lotions, and sticks. The concentration can vary considerably, such as 4.75 percent, 20 percent, 23.8 percent, up to 100 percent. Various studies have found a direct correlation between DEET concentration and hours of protection against insect bites. Fradin and Day (2002) found that a product with 23.8 percent DEET provided an average of five hours of protection against insect bites, compared to four hours of protection offered by a product with 20 percent DEET, while a 6.65 percent DEET product provided almost two hours of protection, and a product with 4.75 percent DEET provided roughly 1.5 hours of protection. Matsuda et al. (1996) found a 100 percent DEET solution offered up to 12 hours of protection, while several lower concentration DEET formulations (20-34 percent) offered three to six hours of protection. Other research has corroborated the effectiveness of DEET (Williamson 2002).

Effects on health

One can be exposed to DEET through contact with the skin or eyes, inhalation, or swallowing. For example, one may inhale the spray if used in indoor spaces where vapors remain and may swallow DEET if the hands are not washed after applying (NPIC 2008). If DEET gets into the eyes, one can experience pain, irritation, and watery eyes, and extended exposure to the skin can result in redness, a rash, irritation, and swelling (NPIC 2008). Swallowing DEET can result in upset stomach, vomiting, and nausea (NPIC 2008).

As a precaution, manufacturers advise that DEET products should not be used under clothing or on damaged skin, and that preparations be washed off after they are no longer needed or between applications (CDC 2008).

In the DEET Reregistration Eligibility Decision (RED), the EPA reported 14 to 46 cases of potential DEET-associated seizures, including 4 deaths. The EPA states: "…It does appear that some cases are likely related to DEET toxicity," but observed that with thirty percent of the U.S. population using DEET, the likely seizure rate is only about one per 100 million users (EPA 1998). There has been a report that "Everglades National Park employees having extensive DEET exposure were more likely to have insomnia, mood disturbances, and impaired cognitive function than were lesser exposed co-workers" (EXTOXNET 1997).

The American Academy of Pediatrics (AAP) states that a concentration of 10 percent appears to be as safe for children as products with a 30 percent concentration, although they do not recommend use of repellents with DEET for infants less than two months old (CDC 2008). They further recommend that DEET be applied no more than one time a day for children older than two months and that the lowest concentrations of DEET available be used (NPIC 2008). It is generally not advised to apply on the hands of children, nor near the mouth or eyes. Note that these are recommendations for children not considered to be at risk of serious vector-borne diseases.

Studies have shown that a small amount of the DEET applied to skin is taken into the body, and that this intake is greater if DEET and alcohol both are applied to the skin. The DEET taken into the body remains in the blood for up to 12 hours. However, all of the DEET is broken down by the liver into smaller chemicals and eliminated from the body, largely through the urine, with nearly all of the DEET eliminated from the body within 24 hours of application (NPIC 2008).

Evidence has not been found that DEET causes cancer in humans or animals, and it has been classified by the U.S. Environmental Protection Agency as "Not Classifiable as a Human Carcinogen," meaning there is not enough evidence that it does or does not cause cancer (NPIC 2008).

Effects on the environment

Although few studies have been conducted to assess possible effects on the environment, DEET is a moderate chemical pesticide and may not be suitable for use in and around water sources. Because it is so commonly used, it has been found in wastewater and other bodies of water impacted by wastewater. DEET has been detected in significant levels in waterbodies as a result of production and use, such as in the Mississippi River and its tributaries, where a 1991 study detected levels varying from 5 to 201 ng/L (Zeiger et al. 1999).

In the soil, it can be broken down by fungi, bacteria, and other microorganisms, and experiments have shown that fungal and bacterial breakdown products were less toxic than DEET itself (NPIC 2008). Likewise, as a mist or vapor in the air, it breaks down as well (NPIC 2008).

DEET has been found to have a slight toxicity for coldwater fish such as the rainbow trout (EPA 1980) and the tilapia (Mathai et al. 1989), and it has also been shown to be toxic for some species of freshwater zooplankton (Seo et al. 2005). In very high concentration, about 75,000 times greater than the highest concentrations found in streams or wastewater, DEET was extremely toxic to freshwater fish and insects, killing half of the fish and insects (NPIC 2008). DEET is not expected to bioaccumulate.

Alternatives

Picaridin (KBR 3023) is another repellent recommended by the Centers for Disease Control and Prevention (CDC); permethrin is recommended for use on clothing, shoes, bed nets, and camping gear, but not directly to the skin (CDC 2008).

Studies have shown eucalyptus-based repellents that contain the natural oil eucalyptol to be a highly effective and nontoxic alternative to DEET (O'Conner 2008). Oil of lemon eucalyptus was found to offer similar protection as repellents with low concentrations of DEET (CDC 2008).

Citronella oil has been used as an insect repellent for 60 years (EPA 1999). Its mosquito repellent qualities have been verified by research (Jeong-Kyu 2005; Jantan and Zaki 1998; Trongtokit et al. 2005); however, the repellency duration of DEET is much greater (Fradin and Day 2002).

A test of various marketed insect repellents by an independent consumer organization found that synthetic repellents (DEET and picaridin) were more effective than repellents with "natural" active ingredients. All the synthetics gave almost 100 percent repellency for the first 2 hours, whereas the natural repellent products tested were most effective for the first 30-60 minutes and then required reapplication to be effective over several hours (Choice 2005). Likewise, the CDC suggests the repellents with DEET or picaridin provide longer-lasting protection than other products, while oil of lemon eucalyptus provides longer-lasting protection than other plant-based repellents (CDC 2008). While most essential oil based repellents are not as effective as DEET (Fradin and Day 2002; Collins et al. 1993), some research also suggests that some essential oil based formulas are comparable to DEET, and somewhat better specifically as mosquito repellant (Trongtokit et al. 2004).

References
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