Mosquito on a bottle of herbal mosquito repellent.
An insect repellent is a substance applied to skin, clothing, or other surfaces which discourages insects (and arthropods in general) from landing or climbing on that surface.
There are also insect repellent products available based on sound production, particularly ultrasound (inaudibly high frequency sounds). These electronic devices have been shown to have no effect as a
pest repellent by studies done by the EPA and many universities.[1]
Insect repellents help prevent and control the outbreak of insect-borne diseases
such as malaria, Lyme disease, Dengue fever, bubonic plague, and West Nile fever. Pest animals commonly serving as vectors for
disease include the insects flea, fly, and mosquito; and the arachnid tick.
Common insect repellents include:
Usually insect repellents work instead by masking human scent, or by using a scent which insects naturally avoid.[citation needed] Permethrin is different in that it is actually a contact insecticide.
Repellent effectiveness
Synthetic repellents tend to be more effective than 'natural' repellents.[3][4][2]
However, some plant-based repellents are comparable to, or somewhat better than synthetics - depending on the formulea.[5] [3][6]
Essential oil repellents tend to being short-lived in their effectiveness due to their
volatile nature.
A test of various insect repellents by an independent consumer organization found that repellents containing DEET or picaridin
are more effective than repellents with ‘natural’ active ingredients. All the synthetics gave almost 100% repellency for the
first 2 hours, where the natural repellent products were most effective for the first 30-60 minutes, and required reapplication
to be effective over several hours.[7]
For protection against mosquitos, the U.S. Centers for Disease
Control recommend DEET, icaridin, or oil of lemon eucalyptus for skin, and permethrin for clothing, gear, or
bed nets.[8] Oil of
lemon eucalyptus was found to be more effective than other plant-based treatments, and had similar effectiveness to low
concentrations of DEET. [9] However, research found
that neem oil is mosquito repellent for up to 12 hours.[10]
Citronella oils mosquito repellency has also been verified by research,[11] including effectiveness in repelling Aedes aegypti,
[12][13], but requires reapplication after 30-60 minutes.
Repellent safety
Regarding safety with insect repellent use on children and
pregnant women:
- Children may be at greater risk for adverse reactions to repellents, in part, because their exposure may be greater.
- Keep repellents out of the reach of children.
- Do not allow children to apply repellents to themselves.
- Use only small amounts of repellent on children.
- Do not apply repellents to the hands of young children because this may result in accidental eye contact or ingestion.
- Try to reduce the use of repellents by dressing children in long sleeves and long pants tucked into boots or socks whenever
possible. Use netting over strollers, playpens, etc.
- As with chemical exposures in general, pregnant women should take care to avoid exposures to repellents when practical, as
the fetus may be vulnerable.
Regardless of which repellent product used, it is recommended that the label is read before use
and directions carefully followed.[14] Usage instructions for repellents vary from country to country. Some insect
repellents are not recommended for use on younger children.[9]
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 30% of the US population using DEET, the likely seizure
rate is only about one per 100 million users.[15]
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". [16]
The U. S. Environmental Protection Agency states that
citronella oil shows little or no toxicity and has been used as a topical insect repellent for
60 years. However, the EPA also states that citronella may irritate skin and cause dermatitis
in certain individuals.[17] Canadian regulatory
authorities concern with citronella based repellents is primarily based on data-gaps in toxicology, not on incidents.[18]
[19]
See also
References
- ^ EurekaAlert (April 17 2007). Mosquito repellents that
emit high-pitched sounds don't prevent bites. Press release.
- ^ a b Safety Tips on Using Personal Insect Repellents. Responsible Pesticide Use. Pest
Management Regulatory Agency (Canada) (17 Sep 2004).
- ^ a b M. S. Fradin and J. F. Day (2002).
"Comparative Efficacy of Insect Repellents against Mosquito Bites". N Engl J
Med 347 (1): 13-18. DOI:10.1056/NEJMoa011699.
- ^ Collins, D.A.; Brady, J.N.; Curtis, C.F.
(1993). "Assessment of the efficacy of Quwenling as a Mosquito repellent". Phytotherapy
Research 7 (1): 17-20.
- ^ Mishra AK, Singh N, Sharma VP, 1995 "Use of neem oil as a mosquito
repellent in tribal villages of mandla district, madhya pradesh", Indian J Malariol, Sep;32(3):99-103 Pubmed
- ^ Collins, D.A.; Brady, J.N.; Curtis, C.F.
(1993). "Assessment of the efficacy of Quwenling as a Mosquito repellent". Phytotherapy
Research 7 (1): 17-20.
- ^ "Test: Mosquito Repellents, The Verdict" Choice, The Australian Consumers
Association
- ^ M. S. Fradin and J. F. Day (2002).
"Comparative Efficacy of Insect Repellents against Mosquito Bites". N Engl J
Med 347 (1): 13-18. DOI:10.1056/NEJMoa011699.
- ^ a b Insect Repellent Use and Safety. West Nile Virus. Centers for Disease Control and Prevention (12 Jan 07).
- ^ Mishra AK, Singh N, Sharma VP, 1995 "Use of neem oil as a mosquito
repellent in tribal villages of mandla district, madhya pradesh", Indian J Malariol, Sep;32(3):99-103 Pubmed
- ^ Jeong-Kyu KIM, Chang-Soo KANG, Jong-Kwon LEE, Young-Ran KIM, Hye-Yun HAN,
Hwa Kyung YUN, Evaluation of Repellency Effect of Two Natural Aroma Mosquito Repellent Compounds, Citronella and
Citronellal, Entomological Research 35 (2), 117–120, 2005
- ^ Ibrahim Jantan, and Zaridah Mohd. Zaki, Developemnt of
environment-friendly insect repellents from the leaf oils of selected Malaysian plants, ASEAN Review of Biodiversity and
Environmental Conservation (ARBEC), May 1998.
- ^ Trongtokit Y, Rongsriyan Y, Komalamisra N, Apiwathnasom L, Comparative
repellency of 38 essential oils against mosquito bites, Phytother Res. 2005 Apr;19(4):303-9 [1]
- ^ "Health Advisory: Tick
and Insect Repellents", Information factsheet, Department of Health, New York State
- ^ "Reregistration Eligibility Decision: DEET." U.S. Environmental Protection Agency, Office of
Prevention, Pesticides, and Toxic Substances. September 1998. pp39-40
- ^ http://pmep.cce.cornell.edu/profiles/extoxnet/carbaryl-dicrotophos/deet-ext.html
- ^ U.S. EPA Citronella Factsheet. Retrieved on July 20, 2007.
- ^ (17 Sep 2004) Re-evaluation of Citronella
Oil and Related Active Compounds for Use as Personal Insect Repellents. Pest Management Regulatory Agency (Canada). ISBN
0-662-38012-6.
- ^ "So Then: Who’s Afraid of Citronella Oil? Update!" Cropwatch Newsletter Vol 2,Issue 1, No. 1
External links
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