Potential Distribution of Chagas Disease in North America

Chagas disease kills thousands of people every year, causing heart failure in otherwise healthy humans. Chagas disease was considered as a tropical disease, but recently it has been compared with HIV as a worldwide problem. The parasite that causes this disease Tripanosoma cruzi, is transmitted by the kissing bug Triatoma gerstaeckeri. T. gerstaeckeri is endemic to South Texas and Northern Mexico. Climate change can potentially alter the distribution of kissing bugs and the rate and incidence of Chagas disease in North America. We collected kissing bugs in South Texas in order to develop models of present and future distribution for T. gerstaeckeri by correlating geographic data with climatic variables using a maximum entropy approach. Three different general circulatory models were used (CCCMA, CSIRO, and Handley) and two IPCC scenarios (A2 and B2). One hundred models were developed and evaluated via cross validation dividing the presence data into 60% and 40% using the Area Under the Curve (AUC) in a ROC plot. Final model and AUC are the average of the 100 models.  All models had AUC > 0.90, which indicate that the models are robust.  Our findings show a potential shift in the distribution of T. gerstaeckeri to northern areas of its original range due to climate change. It is imperative to develop strategies to control the expansion of kissing bugs in those areas as well to control them in endemic areas as it has been done in South America.