La variación del nicho ecológico de Triatoma infestans en el Gran Chaco Americano

Abstract

Triatoma infestans is the main vector of Trypanosoma cruzi (causal agent of Chagas disease) in the southern cone countries of South America, although its geographic distribution reduced 90% after the joint effect of vector control programmes and a number of socio-economic factors that operated in the area during the last 60 years. The objective of this article is to compare at a macro scale the ecological niche of T. infestans where it still persists colonising rural houses with the one that once occupied but it is not present any more, all within the Gran Chaco Americano. The analysis was carried out using data on environmental variables produced by remote sensors and present in the Worldclim database, on temperature and precipitation. The approach of species distribution modelling using a generalized linear model was used, together with a method of niche comparison that estimate niche overlap, equivalency and similarity. Results show that present and past niches are equivalent, with very few differences in similarities. The niche that currently occupies T. infestans remains similar along the axis of climate variability and low temperatures, but it is reduced along the axis defined by precipitation and high temperatures, towards areas with less rainfall and warmer.