Triatomine bugs (Hemiptera, Reduviidae, Triatominae) in the Domiciles of the Guaribas Valley Territory, in Northeastern Brazil.

Introduction: Triatomine bugs are hematophagous insects that are extremely important in public health because they are natural vectors of Trypanosoma cruzi, the causative agent of Chagas disease. In this study, we aimed to assess the occurrence of triatomine species and the natural T. cruzi infection in the Guaribas Valley territory, an endemic region for Chagas disease in northeastern Brazil.

Methods: Insects were actively captured from July 2017 to October 2019 in the intra- and peridomiciles of 16 municipalities of the Guaribas Valley territory, in the southeast area of Piauí state. Triatomine species were identified following a taxonomic key, and natural infection was investigated through insects' fresh feces exams.

Results: A total of 430 triatomines were collected, including 211 nymphs and 219 adults. Of all collected specimens, 39 (9.1%) were from the intradomiciles and 391 (90.9%) from peridomiciles. Nine species, including two subspecies, could be identified: Triatoma brasiliensis brasiliensis, T. brasiliensis macromelasoma, T. pseudomaculata, T. sordida, T. juazeirensis, T. melanocephala, Panstrongylus lutzi, Rhodnius domesticus, R. nasutus, and R. robustus. T. brasiliensis were the most frequently collected bugs, representing 72% of all the identified insects. None of the examined invertebrates presented flagellate forms of T. cruzi.

Conclusions: This is the first report of T. b. macromelasoma and T. juazeirensis in the Guaribas Valley territory. The persistence of triatomine species in the domiciles in an endemic area for Chagas disease emphasizes the relevance of entomological surveillance and vector control measures in the studied area.