Projected future distributions of vectors of Trypanosoma cruzi in North America under climate change scenarios.
BACKGROUND
Chagas disease kills approximately 45 thousand people annually and affects 10 million people in Latin America and the southern United States. The parasite that causes the disease, Trypanosoma cruzi, can be transmitted by insects of the family Reduviidae, subfamily Triatominae. Any study that attempts to evaluate risk for Chagas disease must focus on the ecology and biogeography of these vectors. Expected distributional shifts of vector species due to climate change are likely to alter spatial patterns of risk of Chagas disease, presumably through northward expansion of high risk areas in North America.


RESULTS
We forecast the future (2050) distributions in North America of Triatoma gerstaeckeri and T. sanguisuga, two of the most common triatomine species and important vectors of Trypanosoma cruzi in the southern United States. Our aim was to analyze how climate change might affect the future shift of Chagas disease in North America using a maximum entropy algorithm to predict changes in suitable habitat based on vector occurrence points and predictive environmental variables. Projections based on three different general circulation models (CCCMA, CSIRO, and HADCM3) and two IPCC scenarios (A2 and B2) were analyzed. Twenty models were developed for each case and evaluated via cross-validation. The final model averages result from all twenty of these models. All models had AUC >0.90, which indicates that the models are robust. Our results predict a potential northern shift in the distribution of T. gerstaeckeri and a northern and southern distributional shift of T. sanguisuga from its current range due to climate change.


CONCLUSIONS
The results of this study provide baseline information for monitoring the northward shift of potential risk from Chagas disease in the face of climate change.
Department of Biology, The University of Texas-Pan American, Edinburg, Texas, United States of America.
Miroslava
M
Garza
Department of Biology, The University of Texas-Pan American, Edinburg, Texas, United States of America.
Teresa Patricia
TP
Feria Arroyo
Department of Biology, The University of Texas-Pan American, Edinburg, Texas, United States of America.
Edgar A
EA
Casillas
Laboratorio de Sistemas de Información Geográfica, Instituto de Biología, Universidad Nacional Autónoma de México, Distrito Federal, Mexico.
Victor
V
Sanchez-Cordero
Section of Integrative Biology, University of Texas at Austin, Austin, Texas, United States of America.
Chissa-Louise
CL
Rivaldi
Section of Integrative Biology, University of Texas at Austin, Austin, Texas, United States of America.
Sahotra
S
Sarkar
D000818:Animals; D014355:Chagas Disease / Q000635:transmission*; D057231:Climate Change; D017753:Ecosystem; D007303:Insect Vectors / Q000502:physiology*; D008954:Models, Biological; D009656:North America; D014224:Triatoma / Q000502:physiology*