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Fighting Zika: Which mosquito repellent to use 

Ward off the pesky bloodsuckers with insect repellent and keep Zika at bay

Mosquito repellents can protect people from getting bitten.
Mosquito repellents can protect people from getting bitten. PHOTO: ISTOCKPHOTO

Mosquito repellents are an important feature in the fight against zika.

But which one to choose? And what is the best way to apply it?

Pharmacists here recommend products containing Deet, a chemical compound with a proven safety track record, which has been used for decades. It is highly effective against mosquitoes and also biting flies, fleas and ticks.

Most repellents pose few side effects if used according to instruct- ions, said Ms Clara Lin, a pharmacist with Watsons Singapore.

  • Repellent guide

  • Ms Clara Lin, a pharmacist with Watsons Singapore, gives tips on using repellents:


    •Read the directions on label.

    •Use just enough repellent to cover exposed skin.

    •Apply sparingly around ears.

    •Stop using the repellent if it causes skin reaction.

    ••Stick patches onto clothes or to an article close to you.


    •Spray in enclosed areas or near food.

    •Apply over cuts, wounds or irritated skin.

    ••Spray directly onto the face.

    •Apply to eyes and mouth.

    •Use Deet with sunscreen as it may make the sun protection factor (SPF) less effective. Apply sunscreen first and apply the repellent 15 minutes later.

    •Apply the patch directly onto the skin.

    • Apply to your child's hands as it is likely to make contact with his eyes or mouth.

A newer compound, Picaridin, has been found to be as effective as Deet in protecting against mosquitoes.

Generally, when these are used as directed, they have proven to be safe and effective, even for pregnant and breastfeeding women, said Ms Zoe Kong, principal pharmacist at National University Hospital.

The benefits of preventing mosquito bites far outweigh the risk of getting the Zika virus transmitted from bites, said Ms Lin.

Deet has been shown to be safe in the second and third trimester of pregnancy. However, during the first trimester, it should be sprayed onto the clothing instead of the skin to minimise absorption.

But, as with any product, there is a possibility of developing side effects when using mosquito repellent, said Ms Lin.

Side effects, including skin redness, rashes or a slight burning sensation, are usually temporary and will go away once you stop using the product.

You should avoid using products which contain ingredients you are allergic to. Inhalation of Deet and other repellents in large amounts can cause throat and bronchial (airway) irritation, as well as coughing.

Some repellents which emit smoke or vapours such as mosquito coils, scented candles or liquid vaporisers, may aggravate asthma conditions and trigger wheezing.

To minimise these side effects, do not spray the insect repellent directly onto your face. Spray onto your hands first before applying it to your face, said Ms Lin.

Repellents should not be used on babies younger than two months old, said Ms Kong. Instead, cover the crib, stroller and baby carrier with mosquito netting, she added.

The choice of mosquito repellent depends on the duration of time spent outdoors.

A higher concentration of repellent will have longer-lasting effectiveness. An insect repellent with 7 per cent Deet lasts about two hours, while one with 15 per cent Deet may last up to four hours, said Ms Lin.

Ng Wan Ching

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A version of this article appeared in the print edition of The Straits Times on September 06, 2016, with the headline Fighting Zika: Which mosquito repellent to use . Subscribe