What's Bugging You?

Travel to tropical climates entails contact with a variety of insects capable of transmitting diseases.

• The mosquito is the best known culprit and may transmit malaria, yellow fever, dengue fever, and Japanese encephalitis;
• Ticks can transmit Lyme disease and tick-borne encephalitis;
• Flies offer African sleeping sickness, leishmaniasis, and onchocerciasis or "River Blindness";
• Bugs that live in mud huts spread Chagas' disease; and of course
• Fleas carry plague.

There are specific prevention strategies for malaria (medical prophylaxis), yellow fever and Japanese encephalitis (vaccination), but the majority of insect-borne disease prevention relies on avoiding insect bites altogether.

There are three main ways for individuals to protect themselves from the hungry hordes.

1. Avoid Insects

A. Know your insects--learn about the peak biting times and locations, their different geographic and seasonal distributions. Mosquitoes that carry malaria and Japanese encephalitis bite from dusk to dawn. Those carrying dengue fever and yellow fever bite during the daytime. Ticks are insects that burrow into the skin. They are generally found in forested and grassy areas and on animals. Check your skin for ticks after being in risk areas. Remove ticks by using tweezers to pull steadily perpendicular to the skin. Avoid touching it with bare hands. Fleas are present in sand and soil and on and around animals.

B. Try to arrange accommodations that are well screened, air-conditioned, or have bed nets in good condition.

C. When at the beach, lie on a lounge or at least a blanket or a long towel. Do not lay clothing on the ground or shake them vigorously before re-dressing if you do.

D. In the tropics and subtropics avoid swimming or wading in fresh water and hiking around stagnant ponds and marshes. If fresh water contact occurs, towel dry immediately.

2. Create Physical Barriers

A. Clothing - wear practical wear long sleeved shirts tucked into pants, and pants tucked into socks or boots. Avoid dark or brightly colored clothing and jewelry. Wear shoes that provide maximum coverage. Avoid sandals. Don't go barefoot.

B. Eliminate Fragrance - use unscented hair and hygiene products. Avoid perfumes and aftershave.

C. Bed nets - when accommodations are not adequately screened or air-conditioned bed nets are essential for comfort and protection. Nets should be treated with permethrin and regularly checked for tears and holes. They should be tucked under the mattress.  Treated nets provide some protection even if torn or your skin is against the net. 

3. Create Chemical Barriers

Double the protection tp reduce the risk of bites and disease. Insect repellents produce an effect that causes them not to bite, whereas insecticides act primarily by killing on contact. Some chemicals have both effects. 

A. Repellents - mosquitoes bite people because they need the protein found in blood to help develop their eggs. Mosquitoes are attracted to skin odors and carbon dioxide. Repellents make a person less inviting for feeding. They can be used on skin or clothing.

The two repellents with the highest degree of effectiveness approved for use on the skin are DEET and Picaridin. Typically the higher the concentration the longer the duration of protection. However, with DEET the effectiveness plateaus at about 50%. Because there are variables such as sweating, abrasion from clothing, weather, etc. the duration listed on the label should only be used as a guide and repellent reapplied when biting activity is noticed.

There is a delayed release formulation of 20% DEET which can provide protection up to twelve hours at a lower risk of systemic absorption and local reactions.

Picardin is considered equal to DEET in effectiveness, can be less irritating and won't damage synthetics or plastics, and is now sold in the U.S. in adequate concentrations.

To Use:

• Choose a concentration that provides protection for the amount of time you will be exposed.
• Only use on bare skin and pay particular attention to clothing margins if ticks are a concern.
• Do not spray directly on your face. Spray onto your hands and rub onto your face avoiding eyes and mouth.
• Once back indoors wash treated skin with soap and water.
• Do not use combined sunscreen and insect repellent products. If both are needed apply the sunscreen first. Be aware this may decrease the efficacy of the sunscreen by about a third.

To Use:

• Spraying should be done outdoors and away from food.
• Spray the garments inside and out and allow them to dry for several hours.
• Bed nets, sheets and clothing can be soaked in a permethrin solution which can provide longer lasting protection. Treated nets will last up to six months.