Information on Selecting and using an Insect Repellent

Insect Repellents are generally split into two categories - those based on DEET and DEET-free preparations. All repellents need to be reapplied at regular intervals, especially after swimming and in hot, humid countries, when they can be removed by sweating. When both sunscreens and repellents are used, sunscreen should be applied first and then repellent. The following basic rules apply to the use of all insect repellents:

• Don’t spray directly onto your face.
• Use only on exposed skin.
• Avoid contact with lips and eyes.
• Wash hands after application.
• Don’t apply to cuts, abrasions, broken or irritated skin.
• Wash off the repellent with soap and water when it is no longer needed.
• Sunscreen containing repellent should be avoided.

DEET-based Insect Repellents

The chemical N,N-Diethyl-meta-Toluamide (DEET) has been widely regarded as the most effective insect repellent available for many years.

DEET is available in several strengths suitable for use on skin. Research shows 20% DEET repellents offer protection for up to 3 hours. Higher concentrations give longer-lasting protection, with some 30% DEET repellents providing protection for up to 6 hours. A slow release formulation Ultrathon can give protection for up to 12 hours. In general, the length of protection provided is dependent on factors such as heat, humidity and the amount of sweating.

For general use, a 50% DEET formulation such as Repel 55 provides good protection for around 6 hours. Stronger preparations such as Repel 100 should only be used in the most extreme tropical conditions.

Products containing 50% DEET are safe for use by pregnant and breast-feeding women. DEET should not be used on children under the age of two years. Over this age, a mild strength may be used but particular care must be taken to ensure they are not able to swallow repellent, and that it does not come into contact with their eyes or mouth. Manufacturers instructions regarding age restrictions on products should always be followed.

There have been concerns about the safety of DEET, but research and extensive clinical experience suggest that it is very safe when used according to the manufacturer’s instructions.

DEET-free Insect Repellents

Over the years, many substances have been advocated as alternatives to the use of DEET. Many, if not most, of these have been shown to be relatively ineffective against biting insects.

An exception is the bio-engineered insect repellent Saltidin, which has been available for some 10 years and is generaly considered as the best DEET-free repellent available. It provides equivalent protection to 50% DEET products, and can safely be used on children over the age of two years. Saltidin is the active ingredient in the Ecoguard range of insect repellents.

Other preparations containing various herbal mixtures, Vitamin B or garlic, have very questionable effectiveness and should be avoided. Devices that emit a sonic tone inaudible to humans are not effective.

Other Considerations

Many serious tropical diseases are spread by insects. Some examples are malaria, yellow fever, Japanese encephalitis, dengue fever, West Nile virus, and leishmaniasis. For some of the diseases such as dengue fever, avoiding insect bites is the only way to prevent them. As well asthe use of insect repellents, when travelling in areas where there is a risk of insect-borne disease, other insect bite avoidance measures such as the use of Mosquito Nets should be considered. Further information on these can be found on the National Health Travel Network and Centre website.

---

Associated Products...