What is the etiological agent of visceral leishmaniasis? How is the disease transmitted and what are its typical manifestations?
Visceral leishmaniasis is caused by the protozoan Leishmania donovani. The transmission is similar to the cutaneous leishmaniasis, by the bite of sand flies. The affected organs generally are the liver, the spleen and the bone marrow. The patient often has fever, weight loss, splenomegaly (hypertrophy of the spleen), anemia and decreased counts of leukocytes and platelets. The disease may cause death.