Mapping Climate Change’s Impact on Cholera Infection Risk in Bangladesh

Abstract

AbstractSeveral studies have investigated how Vibrio cholerae infection risk changes with increased rainfall, temperature, and water pH levels for coastal Bangladesh, which experiences seasonal surges in cholera infections associated with heavy rainfall events. While coastal environmental conditions are understood to influence V. cholerae propagation within brackish waters and transmission to and within human populations, it remains unknown how changing climate regimes impact the risk for cholera infection throughout Bangladesh. To address this, we developed a random forest species distribution model to predict the occurrence probability of cholera incidence within Bangladesh for 2015 and 2050. Using R, our random forest model was trained on cholera incidence data and spatial environmental raster data at a resolution of 250 square meters. This model was then predicted to environmental data for the training data year (2015) and for 2050. We interfaced R with ArcGIS to develop risk maps for cholera infection for the years 2015 and 2050, proxying infection risk with cholera occurrence probability predicted by the model. The best-fitting model predicted cholera occurrence given elevation and distance to water. We find that although cells of high risk cluster along the coastline predominantly in 2015, by 2050 high-risk areas expand from the coast to inland Bangladesh with all but the northwestern district of Rangpur seeing increased clusters around surface water. Mapping the geographic distribution of cholera infections given projected environmental conditions provides a valuable tool for guiding proactive public health policy tailored to areas most at risk of future disease outbreaks.