Trypanosoma cruzi I and III populations in northeastern Brazil causing chronic Chagas disease in humans
Trypanosoma cruzi I and III, chronic chagasic patients, clinical forms, genetic diversity
Trypanosoma cruzi, the etiological agent of Chagas disease, is subdivided into six discrete typing units (DTUs) and TcII is most common in human infections in the Brazil. DTUs identification can contribute for understanding the clinical pleomorphism and track sylvatic DTUs threatening the control programs. The genetic identity was analyzed in sixteen Trypanosoma cruzi stocks isolated from 14 chronic chagasic patients with different clinical forms, one from Panstrongylus lutzi and one from Galea spixii from different localities of the State of Rio Grande do Norte, Brazil. T. cruzi isolates were characterized molecularly by genotyping the 3’region of the 24Sα rRNA, the mitochondrial cytochrome oxidase subunit 2 genes (COII), and the spliced leader intergenic region (SL-IRac). T. cruzi DTUs I and III were identified respectively, in 21.5% (3/14) and 28.5% (4/14) of chagasic patients, and DTU II in 50.0% (7/14) of them. DTU III was also identified in P. lutzi and G. spixii. TcI and TcII were isolated from chagasic patients with cardiac, digestive or indeterminate clinical forms, while TcIII was identified only in chagasic patients with indeterminate clinical form. The occurrence of these DTUs revealed notable phylogenetic diversity in T. cruzi isolates from humans and TcIII in humans is reported for the first time in northeastern Brazil. These findings may represent an overlap between the sylvatic and domestic transmission cycles of parasite in the region, and to contribute for understanding the dynamics of T. cruzi populations in northeastern Brazil.