Visceral Leishmaniasis (Kala-azar) in Iran: A Pathologic and Electron Microscopic Study

Five patients with untreated kala-azar who had had the illness for 1, 2, 3, 4, and 5 months, respectively, were studied at autopsy. In the early stage of the disease, there is a diffuse infiltration of the reticuloendothelial system by Leishmania donovani. At 2 months, early granulomas comprised of parasite-loaded macrophages, plasma cells, and lymphocytes were found. Necrosis was seen after 3 months. Scarring of the liver and early cirrhosis occurred after 4 months. There were a few granulomas in the spleen, but no giant cells or epithelioid reaction. The lymph nodes at the early stage showed diffuse parasitic infiltration. The parasites disappeared after 3 months without necrosis. The skin, although grossly normal, contained the parasites in the subcutaneous adipose tissue and the sweat glands; therefore, sweat may be important in the transmission of the disease. Electron microscopic studies of the liver showed parasites with a double membrane, nucleus, and basal body. Electron microscopic examination may be useful in differentiating the leishmanias.