Chronic Chagas Disease in the Brazilian Amazon: Serological Survey, Clinical Follow-Up, and Associated Risk Factors.

Abstract

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.