Eco-Epidemiology of Chagas Disease in Chile

Abstract

There are four vector species of Chagas disease in Chile: Triatoma infestans, responsible for the domestic cycle; Mepraia spinolai, the main wild vector; and M. gajardoi and M. para-patrica, two coastal wild species whose importance as vectors is not well known. They are species of dry environments of the central-north region of Chile, whose best predictors of distribution are warm average temperatures and low rainfall. They are found in rock quarries, nests of birds, and small mammals, and T. infestans has sylvatic foci associated with a Bromeliaceae species. While human blood represents 70% of the diet of T. infestans, in M. spinolai this value is 7%, which means that a large part of Chagas disease in Chile is due to T. infestans. However, all species have high percentages of T. cruzi infection. Chagas disease in Chile follows the distribution of T. infestans, and although the cycle of domestic transmission by this vector is interrupted, there is still a constant prevalence and mortality and ascending incidences. Models predict that although climate change will not vary greatly the north-south distribution of vectors, it could increase the reproductive number of the disease, increasing risk areas of Chagas disease.