Attempts to transmit visceral leishmaniasis to man: Remarks on the histopathology of leishmaniasis

Attempts to transmit kala-azar to five human beings suffering from advanced malignant disease by massive injections of cultures of L. donovani in all the cases and additional injections of leishmania from the livers and spleens of infected Syrian hamsters in two cases were negative in four cases during an observation period of from 8 to 17 months.In one case (Case 3) of cylindrical-celled carcinoma of the stomach, the patient became infected after inoculation of cultures of L. donovani. This is the first record of the successful transmission of visceral leishmaniasis in man. The incubation period was less than 5 months.This case was observed for a period of 9 months and during all this time showed no signs or symptoms of kala-azar in spite of a very heavy infection. There was no marked enlargement of the spleen, no fever and no leucopenia.The histological and haematological findings are discussed.The serum of the infected case was lytic for his own strain of L. donovani. The action of normal human serum or flagellates of Leishmania consists of damage to the nuclear wall and the pouring of the nuclear contents into the protoplasm.Two types of cell infection were noted, one in which the protoplasm is packed with parasites as in the case of reticular cells of the spleen and Kupffer cells in the liver, and one in which the cell is relatively slightly parasitized as in the adventitial cells of arteries, trabeculae Of the spleen, Glisson's capsule, the connective tissue forming the stroma of a carcinoma. The infection of the reticular cells of the bone marrow was intermediate between these two types.In spite of their infection Kupffer cells and other infected cells remained actively phagocytic as evidenced by the inclusion in them of plasma cells, lymphocytes and even other infected cells.Connective tissue cells in the stroma of a cylindrical-celled carcinoma and in Glisson's capsule are shown to be potential phagocytes.The factors which determine individual susceptibility to kala-zar are quite unknown.