Assessing the entomo-epidemiological situation of Chagas disease in rural communities in the state of Piaui, Brazilian semi-arid region

Background: In northeastern Brazil, the wild nature of Trypanosoma cruzi vectors has challenged control actions. This study aims to describe the entomological and epidemiological scenario of Chagas disease in rural communities in the state of Piaui. Methods: A cross-sectional study (n=683 individuals/244 dwellings) was carried out to obtain serum samples, sociodemographic data and intra- and peridomestic triatomines. Results: The overall seroprevalence rate was 8.1%, with no positive tests among subjects <30 y of age. Prevalence rates reached 34.3% and 39.1% among subjects 61-75 and >75 y of age, respectively; 1474 triatomines were collected, of which 90.3% were found in peridomiclliary structures and 9.7% inside houses; 87.2% were classified as Triatoma brasiliensis. T. cruzi infection rates in insects were 0.5% by Eight microscopy and 0.9% by culture in NNN/LIT medium. Five cultivated isolates were submitted to molecular genotyping, three of which were identified as T. cruzi I and two as T. cruzi II. Conclusions: Although no vector transmission currently occurs, prevalence rates are high in adults and the elderly. This disease should be targeted by primary healthcare providers. Insect surveillance and control activities should not be discontinued in an environment favourable to the perpetuation of house colonization by triatomines.