Estudo genotípico de Trypanosoma cruzi: epidemiologia e caracterização molecular de isolados do homem, triatomíneos e mamíferos silvestres do Pará, Amapá e Maranhão

The acute Chagas disease (ACD) is endemic in the Brazilian Amazon, and its main transmission route is oral, throughout family and multi-family outbreaks. This route is independent from the colonization of triatomine bugs in dwellings and its occurrence is regular, with mean rates of 100 cases per year and a lethality rate of 5%. The disease has a well-defined spatio-temporal distribution, which makes it a relevant public health concern in the states of Pará, Amapá and Amazonas. The existence of wild mammals and triatomine bugs naturally infected with Trypanosoma cruzi inhabiting different terrestrial and arboreal ecotopes maintains an intense enzootic cycle all over the Amazon region. Molecular profiles of T. Cruzi lineages in the region are associated with mammal reservoirs (including humans), triatomine bugs, ecotopes and clinical manifestations. We analyzed four ACD outbreaks in the municipalities of Barcarena, Belém and Cachoeira do Arari on Pará State, and Santana on Amapá State, based on epidemiologic features (laboratory, parasitological and serological diagnoses, clinical manifestations and the reservoirs and wild triatomines related to the outbreaks). We also investigated the domestic and wild transmission cycles of T. cruzi in São Luis on Maranhão State, without the occurrence of ACD cases. This study comprised molecular genotyping of T. cruzi on the mini-exon gene of the isolates associated with both transmission cycles (humans, mammals and wild triatomine vectors). Parasitological diagnosis was confirmed in 63 patients with the following sensitivity rates: 41.3% (26/63) for the thick blood film method; 58.7% (37/63) for QBC; 79.4% (50/63) for xenodiagnosis; and 61.9% (39/63) for blood culture. The serological diagnosis of 2648 individuals by indirect hemagglutination assay (IHA) was of 3.05% (81/2648), whereas the results of the indirect immunofluorescence test (IIF) were 2.49% (66/2648) for IgG and 2.37% (63/2648) for IgM. All tests carried out in São Luís were negative. A total of 24 mammals, 13 ...