Urban Trypanosoma (Schizotrypanum) cruzi: pathology in white mice of isolates from Panstrongylus geniculatus.

The histopathological alterations produced in white mice (NMRI strain) by isolates of Trypanosoma (Schizotrypanum) cruzi from Panstrongylus geniculatus captured in dwellings of the city of Caracas, Venezuela are reported. The heart, skeletal muscle, liver, spleen, duodenum, colon, lung, and brain were parasitized by all the isolates. All showed strong myotropism, with elevated virulence and severe histopathological alterations in the cardiac and skeletal muscle, and in the smooth muscle of the duodenum, colon, and lung; parasitization of the mononuclear phagocytic system was discrete. These results, in addition to the morphobiological characters reported in a previous paper, suggest that the isolates in question belong to the same type of parasite. The possible causes of this observation are discussed in the light of the heterogeneity of T. cruzi. The epidemiological significance of the existence of these parasite forms in the urban areas of Caracas is emphasized.