Trypanosoma rangeli Tejera, 1920, in chronic Chagas' disease patients under ambulatory care at the Evandro Chagas Clinical Research Institute (IPEC-Fiocruz, Brazil).

We report the finding, the isolation by hemoculture, and the characterization of Trypanosoma rangeli stocks from two chronic Chagas' disease patients who received ambulatory care at the Evandro Chagas Clinical Research Institute (IPEC, FIOCRUZ). Both patients proceeded from Bahia State (Brazil). One of them presented the cardiac form of the disease and the other indeterminate symptomalogy. Giemsa-stained smears of the hemocultures from these patients evidenced that they were coinfected with T. rangeli and Trypanosoma cruzi, with predominance of the former species. These isolates could only be successfully grown in Novy-MacNeal-Nicolle + liver infusion-tryptose supplemented with 20-30% fetal calf serum. After 6 months of serial maintenance, rich and apparently pure cultures of T. rangeli were obtained. Both stocks were analyzed with different approaches and compared with two T. cruzi isolates also from chagasic patients under care at IPEC, besides T. rangeli and T. cruzi reference strains. All stocks were characterized by morphology, biometry, electrophoresis of isoenzymes, and products of kDNA minicircle amplified by polymerase chain reaction. The identification of T. rangeli was largely confirmed by all techniques. Taken together, these data represent the third report on T. rangeli in human hosts in Brazil.