Because no antimalarial is 100% effective, avoiding exposure to mosquitoes in endemic areas is an essential adjunct to any prophylactic regimen. Physicians and travel nurse practitioners should review these specific measures with travelers during pretravel consultations and emphasize the importance of personal protection measures.

CLOTHING
Since the malaria-carrying mosquito (the female anopheles mosquito) feeds primarily from dusk until dawn, travelers can reduce their risk of malaria by limiting evening outdoor activities. If outdoors at night, travelers should wear long-sleeved shirts and long pants to reduce the amount of exposed skin. Clothing provides a physical barrier to biting insects, provided it is sufficiently thick or tightly woven.

INSECT REPELLENTS
Clothing protection is dramatically increased when the fabric is sprayed or impregnated with permethrin. Far more than a repellent, permethrin is an insecticide (chemically related to the naturally occurring insecticide pyrethrum) that can be applied to clothing (as well as mosquito nets, tents, and gear). Insects are knocked down, or killed, on contact with the treated fabric. Permethrin bonds tightly to the fabric and is effective for 2 weeks after spraying the garment, and up to 4 months on stored garments after impregnation with permethrin solution.

DEET
The most effective skin repellents contain DEET and are essential to insect-bite prevention. They should be applied every 4-12 hours, depending upon the formulation, insect activity, and environmental conditions. Repellents containing lemon eucalyptus (Repel Lemon Eucalyptus, Mosi-Guard) are an alternative to DEET, but a natural repellent may not be as effective as a DEET-containing repellent.

DEET & PERMETHRIN REPELLENTS
Using permethrin-treated clothing in conjunction with applying a topical DEET repellent to exposed skin is known as the DoD (Department of Defense) system and is recommended by the Centers for Disease Control (CDC) and travel clinics in the United States, Canada, and Europe. The use of this DoD system gives nearly 100% protection if the skin repellent used contains at least 30% DEET. Keep in mind that no protection system will be 100% effective and you may need to use additional methods (as described in this article) to supplement these repellents.

PROTECTION IN LIVING & SLEEPING QUARTERS
According to a large European survey of tourists who have visited East Africa, sleeping in air-conditioned rooms significantly reduces the incidence of malaria. Those travelers who are not staying in well-screened or air-conditioned rooms should spray living and sleeping quarters in the evening with a pyrethroid-containing insecticide for flying insects (e.g., Raid®, a flying insect spray available at most home and hardware stores). This will eliminate any insects that have entered the room during the day. It may also be helpful to burn mosquito coils or candles, but this is less effective.

MOSQUITO NETS
Travelers who are not staying in air-conditioned or well-screened rooms should take the additional precaution of sleeping under bed nets (mosquito nets); the nets should extend to the floor or be tucked under the mattress to better prevent access by insects. Bed nets treated with permethrin are significantly more effective in preventing mosquito bites than are untreated nets, and they are safe for pregnant women and children. In field studies done in Africa and elsewhere, nets sprayed with permethrin reduced the episodes of malaria by 39% and child mortality by 83% compared to untreated nets.

Mosquito nets also protect against the following:

• Viral encephalitis (e.g., West Nile virus) and filariasis
  
• Black flies (transmit onchocerciasis and filariasis)
  
• Sand flies (transmit leishmaniasis and sandfly fever)
  
• Ticks (transmit Lyme disease, ehrlichiosis, and many other illnesses)
  
• Gnats, greenheads, and no-see-ums

Nets are less important in preventing dengue fever since the mosquitoes that transmit dengue fever are primarily daytime biters.

Summary of Personal Protection Measures Against Insect Bites

• Wear long-sleeved shirts and long pants to reduce the amount of exposed skin.
  
• Apply an insect repellent that contains DEET to your skin.
  
• Use clothing and gear treated with permethrin.
  
• Spray living and sleeping quarters in the evening with a pyrethroid- or permethrin-containing insecticide.
  
• Sleep in an air-conditioned or well-screened room.
  
• Sleep under bed nets (mosquito nets) treated with permethrin if sleeping in an air-conditioned or well-screened room is not possible.

A complete line of insect bite protection products are available through our online catalog.