Leishmania(redirected from Leishmania major)
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a genus of protozoans of the class Mastigophora.
Several species of Leishmania are known, although most are parasites of reptiles. Three species (L. donovani, L. tropica, and L. brasiliensis) are intracellular parasites of man and some animals, such as dogs. The organisms are transmitted by bloodsucking insects (sandflies of the genus Phlebotomus). L. donovani and L. tropica are found in the tropics and subtropics of Eurasia; L. brasiliensis is found in Central and South America. L. donovani is the causative agent of visceral leishmaniasis, or kala-azar, a serious disease of man that is widespread in India, China, and Sumatra; in the USSR, it appears from time to time in Middle Asia.
Leishmanias localize in the cells of the reticuloendothelial system, including those of the lymph nodes. The body is pear-shaped, 2–4 µm long, and has one nucleus and a kinetoplast. In the body of the animal host, the organism develops into a flagellate leptornonad form.
L. tropica, the causative agent of cutaneous leishmaniasis (Penjdeh sore), is morphologically similar to L. donovani. In the USSR, it is found in Middle Asia and Transcaucasia.
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