Leishmania donovani is a parasitic protozoan that causes visceral leishmaniasis, also known as kala-azar. There are several other names or synonyms for Leishmania donovani, such as Leishman-Donovan body, Leishmania infantum, and L. chagasi. These synonyms refer to different strains or variations of the same parasite that cause similar or related diseases. Leishmania donovani is transmitted to humans through the bite of infected sandflies and can cause severe symptoms, including fever, weight loss, anemia, and enlargement of the spleen and liver. Treatment for leishmaniasis typically involves antiparasitic drugs, but prevention through insect control measures and avoiding endemic areas are also important.