Leishmaniasis

Leishmaniasis is a parasitic disease spread by the bite of infected sand flies. There are several different "diseases" caused by Leishmania . In some diseases, the parasite does not spread beyond the site of the bite.  This results in a "cutaneous leishmaniasis" (oriental sore, Jericho boil), which often heals spontaneously.  In other instances, the parasites may spread to the visceral organs (liver, spleen), resulting in "visceral leishmaniasis" (kala-azar or Dum-Dum fever).

Cutaneous forms of the disease normally produce skin ulcers (either painful or painless, with or without a scab) on the exposed parts of the body such as the face, arms, and legs. The disease can produce a large number of lesions, causing serious disability and scarring. People usually develop skin sores within a few weeks (or, sometimes, months) of being bitten.

Visceral leishmaniasis is characterized by irregular bouts of fever, substantial weight loss, swelling of the spleen and liver, and anemia. If left untreated, the fatality rate can be as high as 100%. People with visceral leishmaniasis usually become sick within several months (sometimes years) of being bitten.

According to the World Health Organization, leishmaniasis currently threatens 350 million men, women, and children in 88 countries around the world. More than 90% of the world's cases of cutaneous leishmaniasis occur in Afghanistan, Algeria, Brazil, Iran, Iraq, Peru, Saudi Arabia, and Syria. However, the majority of the cases evaluated in the U.S. were acquired in Latin America, where leishmaniasis occurs from northern Mexico to northern Argentina.

Travelers of all ages are at risk for leishmaniasis if they live in or travel to areas where leishmaniasis is constantly present with low levels of infection . Adventure travelers, Peace Corps volunteers, missionaries, ornithologists, persons who do research outdoors at night, and soldiers are examples of those who might have an increased risk for leishmaniasis, especially the cutaneous form.

The disease is transmitted by female sand flies that feed on the blood of an animal or human host. The parasites can also be transmitted directly from person to person through the sharing of infected needles, which is often the case with the co-infection Leishmania and HIV (the virus that causes AIDS).

Travelers of all ages are at risk for leishmaniasis if they live in or travel to areas where leishmaniasis is constantly present with low levels of infection . Adventure travelers, Peace Corps volunteers, missionaries, ornithologists, persons who do research outdoors at night, and soldiers are examples of those who might have an increased risk for leishmaniasis, especially the cutaneous form.

Be sure to tell your healthcare provider where you have traveled and that you might be at risk for leishmaniasis. He or she may consult with an infectious disease or tropical medicine specialist for diagnosis and treatment.

Diagnosing leishmaniasis can be difficult. Sometimes the laboratory tests are negative even if a person has leishmaniasis. Samples taken from the sore can be examined for the parasite under a microscope and in cultures. A blood test for detecting antibodies to the parasite can be helpful, particularly for visceral leishmaniasis.

Most cases of cutaneous form will heal without treatment, leaving the person immune to further infection. Other forms of leishmaniasis are extremely difficult to treat, often requiring a long course of antiparasitic drugs. These treatments have traditionally been unsatisfactory because of drug toxicity, poor response, different forms of the disease, and the appearance of drug-resistant strains.

If you travel to these areas, you should take preventive measures to reduce contact with sand flies. You should avoid outdoor activities when sand flies are most active (dusk to dawn). Spray living and sleeping areas with an insecticide. You should also use protective clothing and insect repellent for supplementary protection. Clothing should cover as much of the body as possible that can be tolerated in the climate.