Dr. Murai Éva szerk.: Parasitologia Hungarica 23. (Budapest, 1990)

The skin lesions said to be characteristic of dourine in horses, the socalled "thaler plaques", did not appear on guinea pigs. Histopathological examination revealed inflammatory oedema in the subcutaneous connective tissue, accompanied by diffuse and perivascular infiltration by mononuclear cells, primarily plasma cells and histiocytes. By Giemsa staining trypanosomes were demonstrable in the subcutaneous connective tissue, bone marrow (Figs 4 and 5) and, in one case, also in the major blood vessels of the liver. In the spleen there was diffuse hyperplasia. Besides a similar hyperplasia as that seen in the spleen, in the lymph nodes the mass appearance of plasmablasts in the paracortical zone was striking (Fig. 6). There was proliferative glomerulonephritis and tubulonephrosis in the kidney. In the lungs, there was infiltration by mononuclear cells around the arterioles, hyperplasia of the periarterial lymphoid tissue, and fibrinoid degeneration in the wall of blood vessels (Fig. 3). Fibrinoid degeneration of the walls of blood vessels was demonstrable also in the spleen and liver. In the liver, activation of the RES was also observed. In the testicles severe atrophy and focal interstitial infiltration by mononuclear cells, mainly histiocytes, lymphocytes and plasma cells, were seen. Similar phenomena were observed in the epididymis and plexus pampiniformis (Fig. 7). The uninoculated control guinea pigs remained healthy throughout the 38 weeks, gained weight steadily, and no trypanosomes could be demonstrated from them by either method used. Legend to the figures Fig. 2: Severe oedema of the subcutaneous connective tissue in a cachectic guinea pig inoculated with Trypanosoma equiperdum that died 22 weeks postinoculation (PI) Fig. 3: Fibrinoid necrosis in the wall of an arteriole in the lungs from a guinea pig that died 22 weeks after inoculation with T. equiperdum. H. and E., x800 Fig. 4: Subcutaneous connective tissue of a guinea pig that died 22 weeks after inoculation with T. equiperdum. Note severe inflammatory oedema with perivascular infiltration by mononuclear cells. H. and E., x80 Fig. 5: Trypanosoma equiperdum in a bone marrow smear from a guinea pig that died 22 weeks after inoculation. Giemsa staining, x800 Fig. 6: Numerous plasma cells and plasmablasts in the paracortical zone of a lymph node from a guinea pig that died 22 weeks after inoculation with T. equiperdum. H. and E., x250 Fig. 7: Severe inflammation in the plexus pampiniformis, with infiltration by mononuclear cells, in a male guinea pig that died 22 weeks after inoculation with T. equiperdum. H. and E., x80