Riqueza, distribuição e positividade de triatomíneos (Hemíptera: Reduviidae) no município de Pedro II, região norte do Piauí

Abstract

Chagas' disease represents an infectious parasitic condition in which it has an acute and chronic phase, affecting millions of people worldwide in different geographical regions of the planet, especially in those considered to be the poorest. It represents a growing worldwide threat of morbidity and mortality, being classified by the World Health Organization - WHO as a neglected disease. In this context, the recognition of Chagas disease and its transmission dynamics is of fundamental importance, especially where it involves infected people, as well as the different populations of the parasite and the vector species. This study aimed to characterize the richness of triatomines in urban and rural areas in the municipality of Pedro II, in the northern region of Piauí, analyzing the geographic distribution of the species, the positivity for the disease, as well as its prevalence in the peri and intra-household environments. The study was carried out in different locations registered with the municipality's Health Department, with different rates of home infestation by triatomines. The collections were made mainly through active search (manual capture) and passive search using light trap. Between February and October 2019, 376 specimens of triatomines were captured and identified in the municipality of Pedro II, including nymphs belonging to five species: Panstrongylus lutzi, Panstrongylus megistus, Rhodnius nasutus, Triatoma brasiliensis and Triatoma pseudomaculata. All adult insects were examined, with 09 (2.39%) showing flagellates in the intestinal content, with positivity for P. lutzi and T. pseudomaculata. Most insects corresponded to 218 (57.9%) nymph specimens, with the number of adult males 111 (29.5%) predominating over the number of adult females 47 (12.5%). Immature specimens were observed for P. lutzi, T. brasiliensis and T. pseudomaculata, 5th stage nymphs. Among the total of insects captured, 86 (22.8%) were found in the home, 290 (77.1%) in the home. In the home, the main positive rooms were the bedroom and the living room, while in the home the largest number of insects was captured in the chicken coop, where there was a higher density of nymphs. The dispersion index of triatomines in the municipality was 14.9%. The most dispersed species was T. pseudomaculata. In the current context of control of vectorial transmission of T. cruzi in Brazil, in which entomological surveillance activities are carried out at the municipal level, the present study provided information that provides support for the improvement of the respective actions in the municipality of Pedro II, Piauí. From an eco-epidemiological point of view, some recurring questions have been reinforced, such as the importance of T. pseudomaculata as the main household vector in the municipality, differing from other regions. In addition, other issues have surfaced and deserve more in-depth studies, such as home infestation by species of triatomines with little-known ecological characteristics, and the invasion of vectors in an urban environment, which has not yet been studied.