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Leishmaniasis is a parasitic disease that is found in parts of the tropics, subtropics, and southern Europe. It is caused by infection with Leishmania parasites, which are spread by the bite of infected sand flies. There are several different forms of leishmaniasis in people. The most common forms are cutaneous leishmaniasis, which causes skin sores, and visceral leishmaniasis, which affects some of the internal organs of the body (for example, spleen, liver, and bone marrow).
The number of new cases of cutaneous leishmaniasis each year in the world is thought to be about 1.5 million. The number of new cases of visceral leishmaniasis is thought to be about 500,000. In the Western Hemisphere, leishmaniasis is found in some parts of Mexico, Central America, and South America (Latin America). It is not found in Chile or Uruguay. In the Eastern Hemisphere, leishmaniasis is found in some parts of Asia, the Middle East, Africa, and southern Europe. It is not found in Australia or the Pacific Islands.
People who have cutaneous leishmaniasis have one or more sores on their skin. The sores can change in size and appearance over time. They may end up looking somewhat like a volcano, with a raised edge and central crater (ulcer). Some sores are covered by a scab. The sores can be painless or painful. Some people have swollen glands near the sores (for example, under the arm if the sores are on the arm or hand).
People who have visceral leishmaniasis usually have fever, weight loss, and an enlarged spleen and liver (typically, the spleen is bigger than the liver), and some abnormal blood tests. For example, patients usually have low blood counts, including a low red blood cell count (anemia), low white blood cell count, and low platelet count.
The first steps are to check if you have been in a part of the world where leishmaniasis is found and if you have any signs or symptoms that might be from leishmaniasis.
Samples of tissue (for example, from skin sores) can be examined for the parasite under a microscope, in cultures, and through other means.
Blood tests that detect antibody (an immune response) to the parasite can be helpful for cases of visceral leishmaniasis; tests to look for the parasite itself usually are done also.
CDC staff can advise your health care provider and can help with the laboratory testing. Diagnosing leishmaniasis can be difficult. Sometimes the laboratory tests are negative even if a person has leishmaniasis.
The main way is through the bite of infected female phlebotomine sand flies. (Sand flies become infected by biting an infected animal or person.) People might not realize that sand flies are present because:
Sand flies usually are most active in twilight, evening, and night-time hours (from dusk to dawn). Although sand flies are less active during the hottest time of the day, they may bite if they are disturbed (for example, if a person brushes up against the trunk of a tree or other site where sand flies are resting).
Some types (species) of Leishmania parasites may also be spread by blood transfusions or contaminated needles (needle sharing). Congenital transmission (spread from a pregnant woman to her baby) has been reported.
Your health care provider can talk with CDC staff about whether your case of leishmaniasis should be treated, and, if so, with what type of therapy.
The skin sores of cutaneous leishmaniasis usually will heal on their own, even without treatment. But this can take months or even years, and the sores can leave ugly scars. Another potential concern applies to some (not all) types of the parasite found in South and Central America: occasionally, the parasite spreads from the skin to the nose or mouth and causes sores there (mucosal leishmaniasis). Mucosal leishmaniasis might not be noticed until years after the original skin sores healed. The best way to prevent mucosal leishmaniasis is to treat the cutaneous infection before it spreads.
If not treated, severe (advanced) cases of visceral leishmaniasis can cause death.