Sunday, May 6, 2012

DEET is the best choice against mosquitoes, isn't it?

Mosquito-borne diseases like malaria and Dengue Fever are on the rise world-wide, from “first-world” Florida in Southern USA and Southern Australia to gorgeous tropical South East Asia, Africa, India and South America.  Yes, they make a lot of people very sick; malaria alone killed an estimated 1,238,000 people globally in 2010, according to a University of Queensland study published in the prestigious Lancet magazine.  Staggering numbers.  And that doesn’t count the number of people who just got miserably feverish and sick for months on end, nor does it account for the substantial number of deaths from Dengue Fever.  So that smart thing to do is use a proven mosquito repellent like DEET, right?  I mean, safety first, right?  Agreed, safety first.  But if you’re truly concerned about health and safety, then DEET as a choice for mosquito protection is very wrong.  Here’s why.

DEET (developed and originally manufactured by those same caring and health-conscious US army people who created Agent Orange during the Vietnam War) has been officially classified by the USFDA as a Group D carcinogen (cancer causing agent) and is believed to be an endocrine disruptor, which means it has effects on the reproductive and hormone systems in the body.  Important to note that many cancers are oestrogen dependent, so a disturbed hormone level and response in the body can contribute to the growth and development of many cancers.  DEET has been proven to be a neuro-toxin and to cause both kidney and liver damage.  It is a skin irritant and can cause scarring.  DEET is currently being studied for its contributing role in birth defects and developmental problems in children, hence it is NEVER to be used on children under 6 years of age.  DEET has been detected in ground-water around the world and is also a serious environmental contaminant. 

But the natural sprays don’t work well or, if they do, only for a little while…

For an essential oil to be effective as an insect/mosquito repellent, it has to be at a high enough concentration.  Many natural insect sprays use only 5% concentration, which is simply not enough. Why so low?  Many of the people making the product either aren’t well trained or well read, or are looking to optimize profit and/or maybe not so very interested in your long-term health.

Citronella oil is the most common ingredient in most natural insect repellent sprays, but it is also the least effective over time.  Why do most people choose to use it so much?  Because it’s relatively cheap.  Other oils like basil and clove are incredibly effective but expensive and need to be used carefully at very specific concentrations so as not to burn the skin.  And some oils like neem that are highly effective insect repellents and anti-malarials are simply not known for that purpose; for example, Thai people eat neem leaves with curry (called sadao locally) to prevent intestinal parasites but mostly don’t know about it’s wonderful medicinal uses as an oil for the skin or as an anti-malarial insect repellent.

So what evidence is there for good natural alternatives to DEET?

Field studies on the mosquito repellent action of neem oil.  Sharma SK, Dua VK, Sharma VP.  Source:  Malaria Research Center (Field Station), BHEL Complex, Ranipur, Hardwar, India.
Abstract :  Repellent action of neem oil was evaluated against different mosquito species. 2% neem oil mixed in coconut oil provided 96-100% protection from anophelines, 85% from Aedes, 37.5% from Armigeres whereas it showed wide range of efficacy from 61-94% against Culex spp. Therefore, neem oil can be applied as a personal protection measure against mosquito bites.

Phlai Essential Oil, Sweet Basil Essential Oil  The plant oil group was comprised of Phlai (Zingiber cassumunar) and Sweet basil (Ocimum basilicum). Both substances were effective as repellents and feeding deterrents against An. minimus (205 minutes protection time and a biting rate of 0.9%), Cx. quinquefasciatus (165 minutes protection time and 0.9% biting rate) and Ae. aegypti (90 minutes protection time and 0.8% biting rate).  Southeast Asian J Trop Med Public Health. 2010 Jul ;41 (4):831-40  21073057

Citronella Essential Oil  Essential oil from citronella grass (Cymbopogon nardus) exhibited protection against biting from all 3 mosquito species: for An. minimus, Cx. quinquefasciatus and Ae. aegypti, the results were 130 minutes and 0.9%, 140 minutes and 0.8%, and 115 minutes and 0.8%, respectively. Southeast Asian J Trop Med Public Health. 2010 Jul ;41 (4):831-40  21073057

Clove Essential Oil  In a 2005 study that compared the repellent activity of 38 different essential oils, researchers discovered that clove oil offered the longest duration of protection against all mosquito species involved in the lab experiments.

Lemongrass Essential Oil  Lemongrass oil is effective for repelling mosquitoes, according to a 2009 study conducted at Obafemi Awolowo University, which found that a preparation including lemongrass oil was as effective at repelling mosquitoes as commercially available insect repellents.

Other tips:  cover up, wear light colors and don’t drink alcohol.  It is believed the increased CO2 in perspiration from drinking alcohol and eating a high sugar diet (yes, that includes fruit) attracts mosquitoes.  Eating garlic and Vitamin B has also been shown to repel and reduce the rate of mosquito bites.   And using a fan outside during the mosquito-biting hours is smart, safe and easy – mosquitoes HATE moving air.

So if you’re serious about your long term health and safety, don’t use a DEET-based repellent, use other strategies to reduce the risk of biting, and make sure any spray you do choose is both effective and 100% natural.

Footnote:  Arun Thai Natural’s 100% Natural Insect Repellent Spray uses a neem oil concentration of 3.5% against the reported study results, which used 2%.  It also contains 5 other proven effective essential oils – basil, phlai, clove, citronella and lemongrass.  Neem oil is effective for up to 12 hours.

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