Changes in the hamster liver after experimental infection with Schistosoma intercalatum. An ultrastructural study

Syrian hamsters were exposed to cercariae of Schistosoma intercalatum. After 70 days, their livers were fixed by vascular perfusion and samples of liver tissue were studied by the electron microscope. Lesions consisted predominantly of mature egg granulomas, with some in earlier stages of development. The cells involved in both types of lesion are described together with their relation to the egg and the surrounding liver tissue. Only minor abnormalities were seen in the tissue distant from the eggs. These consisted mainly of (a) pigment accumulation, both in Küpffer and endothelial cells; (b) probably aspecific ultrastructural changes in the hepatocytes; (c) occasional slight fibrosis around portal veins. The Schistosoma pigment was compared with malaria pigment induced by infection of a hamster with Plasmodium berghei. The regular, crystalloid hemozoin particles in malaria infection were easily distinguishable from the coarser and irregular pigment deposits in schistosoma infection.