Intestinal amyloidosis in hamsters with visceral leishmaniasis.

Thirty hamsters about 10 weeks old were inoculated intraperitoneally with Leishmania donovani amastigotes and were serially killed after 15, 30, 45, 60, 75 and 85-90 days. Both the small and large intestines were examined grossly, and the histopathology was assessed by light and electron microscopy. The lamina propria and the submucosa of the whole length of the intestinal tract showed a progressive deposition of amyloid, selectively identified by optical and ultrastructural techniques. The presence of amyloid fibrils in the cytoplasm of plasma cells suggests that appearance of intestinal amyloidosis during visceral leishmaniasis may be the result of a pathological dysfunction of these cells. In addition to these deposits, the presence of inflammatory infiltrates containing lymphocytes, plasmocytes and macrophages confirmed the establishment of leishmaniasis. In the end-stages of the infection both vacuolar degeneration of the epithelial cells lining the lumen of the intestine and a moderate hyperplasia of lymphatic nodules was observed.