Leishmaniasis

Leishmaniasis is a parasitic disease acquired in tropical and subtropical areas of the world.

Persons become infected through the bite of some species of sand flies. In the Western Hemisphere, the infection usually is acquired in rural areas, but in the Eastern Hemisphere, infection may be acquired in some urban areas as well.

The disease most commonly manifests either in a cutaneous (skin) form or in a visceral (internal organ) form. Cutaneous leishmaniasis is characterized by one or more skin sores (either open or closed) that develop weeks to months after a person is bitten by infected sand flies. The manifestations of visceral leishmaniasis, such as fever, enlargement of the spleen and liver, and anemia, typically develop months, but sometimes years after a person becomes infected.

Vaccines and drugs for preventing infection are not currently available. Preventive measures for the individual traveler are aimed at reducing contact with sand flies. Outdoor activities should be avoided when sand flies are most active (dusk to dawn). Although sand flies are primarily night-time biters, infection may be acquired during the daytime if resting sand flies are disturbed. Sand fly activity in an area may easily be underestimated because sand flies are noiseless fliers, and rare bites may go unnoticed.

Protective clothing and insect repellent should be used for supplementary protection. Clothing should cover as much of the body as possible and tolerable in the climate. Repellent with DEET (N,N-diethylmethyltoluamide) (DEET) should be applied to exposed skin and under the edges of clothing, such as under the ends of sleeves and pant legs. It should be applied according to the manufacturer's instructions; repeated applications may be necessary under conditions of excessive perspiration, wiping, and washing. Although impregnation of clothing with permethrin may provide additional protection, it does not eliminate the need for repellent on exposed skin and should be repeated after every five washings.

Contact with sand flies can be reduced by mechanical means, such as bed nets and screening of doors and windows. Fine-mesh netting (at least 18 holes to the linear inch; some sources say even finer) is required for an effective barrier against sand flies, which are about one-third the size of mosquitoes. However, such closely woven bed nets may be difficult to tolerate in hot climates. Impregnating bed nets and window screens with permethrin aerosol may provide some protection, as may spraying dwelling with insecticides.

Diseases