Penn Travel Medicine






Insect-borne Diseases


Yellow Fever

Traveler's Diarrhea

Insect-borne Diseases

Insects and their relatives — ticks, mites, spiders, and so on — are commonly known as arthropods. This group transmits a variety of diseases that are responsible for approximately 2 percent of deaths worldwide. Diseases transmitted by arthropods range from Lyme disease and West Nile fever in the United States to malaria and dengue fever in areas such as Africa and parts of Asia. In many cases, simple precautions can significantly reduce, if not prevent, the risk of transmission.

Some insect-borne diseases, such as malaria, are reappearing in areas where the disease was thought to be eradicated. Some diseases can be prevented by vaccinations or preventive use of specific medication, but for many other diseases the only preventive measure available is avoiding arthropod bites in the first place.

Preventing Bites

  • Covering as much skin as possible is an important precaution against arthropod bites. If possible, long-sleeved shirts tucked into long pants are recommended in areas where arthropod-borne diseases are common. A hat will help to protect your face.

  • When hiking in forests or jungles, pants should be tucked into socks. Open shoes should not be worn on hikes. Light colored clothes help detect ticks more easily. According to the CDC, prompt removal of attached ticks can prevent some infections.

  • Exposed skin should be covered in insect repellent containing the chemical DEET (N,N-diethylmetatoluamide). The higher the DEET concentration — up to 30 percent — the longer the protection provided by the repellent. Studies show that no increased protection occurs in concentrations over 30 percent. The recommended concentration for children is 20 percent, and the maximum concentration allowed for children is 30 percent. Do not use DEET-containing repellents under clothes, and wash your skin when coming back indoors. Do not spray repellent on face, instead spray on your hands and apply to face.

  • A new controlled-formula containing 20 percent DEET is now available on the market. It provides longer lasting protection with lower concentration of DEET, while greatly minimizing the amount of DEET that's absorbed through the skin.

  • Cover clothes and shoes in repellent containing permethrin. After spraying permethrin on clothes, allow them to dry before wearing. Permethrin will bind to fabric, and can last through five washing cycles. Never apply permethrin to skin.

  • If you sleep in non-screened, non-air-conditioned accommodations use bed nets, preferably treated with permethrin. Nets should be tucked firmly under the mattress, or extend all the way to the floor. Before using the net, make sure it isn't torn, and check that no mosquitoes are inside the area you are going to protect with the net. Nets should have a mesh size no larger than 1.5 mm. Permethrin protection can last for months on unwashed nets. Bed nets are available in sporting goods stores.


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