In a field study by the US military in Alaska, subjects who wore Permethrin-treated uniforms and 35-percent DEET on exposed skin had 99.9- percent protection with one insect bite per hour over an eight-hour period compared to 1,188 insect bites per hour in a control group that had no protection.

"Many people apply insect repellent to their skin, but if you're going to be camping or spending a lot of time outdoors, you should also treat clothing, tents and other outdoor fabrics with a product called Permethrin," said William Stauffer, M.D., of Regions Hospital's Center for International Health in St. Paul, Minnesota.

This dual approach, which is very effective against malaria in tropical areas, also is very effective in areas where mosquitoes are more prevalent in summer than in the tropics, Dr. Stauffer says.

Protect Your Skin

"DEET, which has been used worldwide for 40 years, is the safest, most thoroughly studied, and effective chemical repellent currently available," notes Dr. Stauffer.

For adults and children, he recommends a time-release controlled DEET product (e.g., Ultrathon, Sawyer), which may last up to 12 hours, despite being less than 30 percent DEET.

When using a regular product with DEET, the time of protection is dependent on concentration. For adults and children, a product containing 25-50 percent DEET offers at least four hours of protection.

"When used properly, DEET is very safe for kids," says Dr. Stauffer, "especially if you factor in the risks of contracting Lyme disease, West Nile encephalitis, and other insect-borne illnesses."

Protect Your Clothing

Using the insect repellant Permethrin on clothing, in addition to DEET, offers additional protection, says Dr. Stauffer. It was developed for the US military and remains effective for at least two weeks and up to six months depending on the amount applied, even after repeated launderings.

In a field study by the US military in Alaska, subjects who wore Permethrin-treated uniforms and 35-percent DEET on exposed skin had 99.9-percent protection with one insect bite per hour over an eight-hour period compared to 1,188 insect bites per hour in a control group that had no protection.

Symptoms of Disease

West Nile virus causes fever, headache, body aches, nausea, vomiting, swollen lymph glands or rash in about 20 percent of those infected.

Lyme disease is transmitted by Deer ticks and can cause debilitating arthritis, as well as serious heart and nervous system problems. One early symptom of Lyme disease is a "bulls-eye" rash, consisting of a reddened area, sometimes with a clear area in the middle.

Other symptoms include fever, headache, chills, and pain in the muscles or joints.