Predictions of Future Geographical Distribution of Two Vectors of American Trypanosomiasis: Implications for Endemic Chagas disease in Texas, USA

Abstract

It is known that climate has a direct effect on vectorborne and zoonotic diseases, and in the face of climate change, understanding this link has become more urgent. Many such vector-borne diseases primarily afflict impoverished populations and have therefore been previously understudied. One major focus of our research is to understand the influence that climate has on the distribution of disease causing microorganisms and their vectors, especially those in relation to American trypanosomiasis (Chagas disease). Chagas disease is caused by the hemoflagellate protozoan parasite, Trypanosoma cruzi. For this study, we hypothesized that the increasing prevalence Chagas in the state of Texas is due to expanding distributions of vectors. To test this hypothesis, historical data on vector distribution and climate was used to determine the probable locations of prevalent vectors in Texas. Predictions for the future distributions were made using environmental niche models for bioclimatic variables with a maximum entropy algorithm. Of the two Triatominae species studied, the range and concentration of both decreased under a global warming scenario, a finding that is consistent with the current research of risk of Chagas disease in Venezuela. In future, this same procedure will be used on more Chagas vectors to better understand if there is a northward shift for vectors, or if Texas is becoming more inhospitable to all vectors of Chagas.