Wednesday, 21 September 2016

Safety of mosquito repellents

Why do we need mosquito repellent?

Mosquito-borne illnesses are diseases that are spread by mosquitoes. The common examples are Dengue, Chikungunya, Malaria and the recent outbreak of Zika. 

We can prevent the mosquito-borne illness by preventing mosquitoes from biting, as disease transmission occurs when the mosquito bites. 

There are many mosquito repellents in the market, some that we spray on clothes, some with roll-ons, clips and etc. But how safe are these products, especially to be used by young children and pregnant mothers? 

Let’s look into common mosquito repellents and it's ingredients. 

One of the key ingredients of mosquito repellents is Diethyltoluamide or DEET. DEET is present in varying concentration depending on the brand of the repellent.

DEET was originally developed by the American army to be used by their soldiers during wartime in the jungle. It’s a yellow oil and has a strong smell which is disliked by insects such as mosquitoes. Thus it effectively repels them. 

How safe is DEET? 

In a 2014 review by the US Environmental Protection Agency1, it was concluded that DEET does not cause any harm to adults, pregnant mothers or children when used properly. Proper usage means using it on clothes, or exposed skin and not applying it over wounded skin or under clothes. This is also supported by doctors from Harvard Medical Centre2

But products containing DEET are not advised to be used on children under the age of 2 months according to American Association of Pediatrics. Those older than that are safe to use repellents as long as the DEET concentration do not exceed 30%.3

What concentration of DEET to buy?

Depending on the brand of insect repellent, the concentration of DEET varies. The effectiveness of DEET is similar regardless of the concentration of the product. But the duration of action may differ. For example, 10% DEET will provide protection against mosquito bite for about 2 hours and 30% will do the work for 5 hours. 

It’s not recommended to use a product with DEET more than 30%.

Are there any natural alternatives to DEET?
There are many alternatives to DEET. The one with evidence behind it is lemon eucalyptus oil. Often used in natural mosquito repellent products, this oil is proven to be more than 95% effective against mosquitoes for 3 hours when compared to DEET.4
While there are many products in the pharmacy which uses lemon eucalyptus oil in their mosquito repellent, we can also prepare it at home. 

Just mix 1 part of lemon eucalyptus oil to 10 parts of sunflower oil and spray it or rub it on the skin.

Protecting our loved ones and ourselves against mosquito-borne illness is important especially now. 

Always remember to wear long sleeves shirts and pants, and use mosquito repellent when going out especially in the evening.

For further reading:

  1. https://www.epa.gov/insect-repellents/deet
  2. http://www.ncbi.nlm.nih.gov/pubmed/27548647 
  3. https://www.aap.org/en-us/about-the-aap/aap-press-room/news-features-and-safety-tips/pages/summer-safety-tips.aspx 
  4. http://www.ncbi.nlm.nih.gov/pubmed/24772681

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