Leishmaniasis is the general name for a group of diseases caused by parasitic protozoans of the genus Leishmania. These diseases, which occur in 90 tropical and subtropical countries around the world, are transmitted by the bite of sand flies and by direct blood contact via transfusion or needle sharing with an infected person. The parasites infect and cause problems in the skin, mucous membranes, and some internal organs. Nearly two million people in the world are afflicted by the diseases. Three major types of leishmaniasis occur in humans: cutaneous, mucocutaneous, and visceral.

In cutaneous leishmaniasis (also known as aleppo boil, aleppo button, Bagdad boil, Baure ulcer, Delhi boil, oriental sore, and tropical sore) the parasite causes lesions on the face, arms, and legs which begin as inflamed bumps and can turn into nasty skin ulcers that take up to two years to heal.

In mucocutaneous leishmaniasis (also known as American leishmaniasis, Chiclero ulcer, espundia, forest yaws, and uta) the parasite invades the mucous membranes and causes ulcers in the nose, mouth, and parts of the sinuses. This can result in lesions, extreme pain, and deformity of the face.

In visceral leishmaniasis, also known as kala azar (a Hindi term meaning "black fever") or dumdum fever, the parasite invades the spleen, liver, bone marrow, lymph nodes, and skin. Symptoms include fever, fatigue, enlargement of the lymph nodes, the spleen, and the liver, dizziness, weight loss, and secondary infections such as pneumonia. When the protozoan invades the reticuloendothelial system in a person's organs, they cause the formation of tiny characteristic spheres called Leishman-Donovan bodies. Visceral leishmaniasis can cause permanent immune system damage and can be fatal if left untreated.

People are most likely to contract leishmaniasis if they are out and about in rural areas at night in afflicted areas. Field researchers like ornithologists, Peace Corps workers, and soldiers have particularly high rates of catching the disease. There are no vaccines or drugs to protect against the disease, so people in afflicted areas should wear protective clothing and insect repellent containing DEET. People should sleep in rooms or tents protected by fine netting.

Patients with are usually treated with antimony-containing medications like meglumine antimonate and sodium stibogluconate. They are also sometimes given antibiotics like pentamidine and amphotericin B. Plastic surgery may be necessary to correct scarring and facial deformity. People have a high chance of being cured if the disease is caught before it causes permanent damage to the immune system.

Some of the information in this writeup was gleaned from http://www.cdc.gov/travel/diseases/leishmaniasis.htm and http://umm.drkoop.com/conditions/ency/article/001386.htm. The rest was taken from the science dictionary at http://biotech.icmb.utexas.edu/; I oversaw the development of the dictionary (the website was mothballed in 1998) and I believe I wrote the entry this is based on.

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