Trypanosoma cruzi from the Paraguayan Chaco: isoenzyme profiles of strains isolated at Makthlawaiya.

At Makthlawaiya, in the Paraguayan Chaco, the prevalence of Trypanosoma (Schizotrypanum) cruzi infection among both domestic Triatoma infestans and domestic dogs was 38%, and IgG anti-T. cruzi antibody was detected by the quantitative enzyme-linked immunosorbent assay (ELISA) in 80% (105/133) of human sera. Ninety percent (25/28) of T. cruzi strains isolated from both T. infestans and dogs showed heterozygous isoenzyme profiles for glucose phosphate isomerase, phosphoglucomutase and 6-phosphogluconate dehydrogenase. These strains appeared to be closely related to Bolivian zymodeme 2. Three Paraguayan T. cruzi strains showed homozygous isoenzyme profiles, similar to those of major Brazilian zymodemes. It was concluded that T. cruzi strains with heterozygous isoenzyme profiles predominate in domestic transmission cycles in this highly endemic area of the Paraguayan Chaco.