Leila Inês de Aguiar Raposo Câmara Coelho

: The prevalence and characteristics of chronic Chagas disease (CCD) in the Amazon Region remain underexplored. This study aimed to describe the challenges encountered during a serological survey and follow-up of CCD, while also highlighting potential risk factors in the Amazon Region. The serological survey involved residents of periurban and rural areas of Manaus in the Brazilian Amazon. All participants were invited to complete a clinical, epidemiological, and demographic questionnaire and provide a blood sample for anti-Trypanosoma cruzi (T. cruzi) IgG tests. A total of 1,845 participants were included, of whom 43 were identified as having presumed CCD, based on having at least two positive serological tests. Only 35 underwent complementary tests, and five had cardiac alterations not consistent with CCD. The main risk factors associated with CCD were age ≥20 years, living in periurban areas, reporting the presence of the insect vector inside the household, entering the forest, consumption of bushmeat, and having undergone blood transfusion. In the Amazon, the population is exposed to the sylvatic T. cruzi life cycle and is unaware of the associated risk factors. The divergent serology results raise doubts about the reliability of the commercial serological tests used for CCD screening in the region. Surveillance for CCD is important in the Amazon.

Chagas disease in the Amazon region is considered an emerging anthropozoonosis with a predominance of the discrete typing units (DTUs) TcI and TcIV. These DTUs are responsible for cases of acute disease associated with oral transmission. Chronic disease cases have been detected through serological surveys. However, the mode of transmission could not be determined, or any association of chronic disease with a specific T. cruzi DTU’s. The aim of this study was to characterize Trypanosoma cruzi in patients with chronic Chagas disease in the State of Amazonas, Brazil.

In the State of Amazonas, American tegumentary leishmaniasis is endemic and presents a wide spectrum of clinical variability due to the large diversity of circulating species in the region. Isolates from patients in Manaus and its metropolitan region were characterized using monoclonal antibodies and isoenzymes belonging to four species of the parasite: Leishmania (Viannia) guyanensis, 73% (153/209); Leishmania (Viannia) braziliensis, 14% (30/209); Leishmania (Leishmania) amazonensis, 8% (17/209); and Leishmania (Viannia) naiffii, 4% (9/209). The most prevalent species was L. (V.) guyanensis. The principal finding of this study was the important quantity of infections involving more than one parasite species, representing 14% (29/209) of the total. The findings obtained in this work regarding the parasite are further highlighted by the fact that these isolates were obtained from clinical samples collected from single lesions.