Analysis of the geographical distribution of Triatoma vitticeps (Stål, 1859) based on data of species occurrence in Minas Gerais, Brazil

Abstract

The purpose of this study was to determine the potential for infestation of man-made environments by Triatoma vitticeps, correlating the epidemiological importance of this species with that of others present in the Brazilian state of Minas Gerais. In addition, climatic variables that could help explain the distribution of this species and clarify its population dynamics were sought. This was done by carrying out a historical survey of the presence of T. vitticeps in artificial ecotopes, using data from the Fundação Nacional de Saúde (FUNASA). Monthly records of bioclimatic variables averaged for the period 1950-2000 and pixel size of 1. km × 1. km provided a reference for spatial distribution analysis. Annual rainfall and rainfall of the most humid trimester are the best indicators of the species distribution. To confirm the importance of these variables, T. vitticeps eggs were exposed to different levels of relative humidity. Hatching was found to vary significantly, and low humidity showed a significant negative effect on egg hatching. Our results demonstrate a strong association between T. vitticeps and high environmental humidity, which apparently acts as a limiting factor on the distribution of this triatomine.