Impact of Changing Climate on Diarrheal Diseases: A Case Study for Cholera

Diarrheal disease such as cholera remains a global public health threat. While the climatic association of environmental conditions with cholera are well demonstrated, this study examines challenges of climate change on occurrence of disease. Cholera in the Bengal Delta, commonly referred to as a native homeland of disease, has a unique pattern of biannual peaks and is related to asymmetric variability in regional hydroclimatology (primarily streamflow). Intrusion of costal seawater containing cholera bacteria into inland during low flow season causes the first cholera outbreak, while floods during high flows in rivers is associated with second wave of disease outbreak. Course resolution of General Circulate Models (GCM) output cannot be directly linked to cholera, and hence, a framework is introduced to bridge the gap between global climate model outputs and streamflow in the Ganges-Brahmaputra-Meghna rivers to assess how changing climate will impact endemic cholera in Bangladesh. We will show probability of cholera occurrence under different climate change scenarios using results from a machine learning based downscaling algorithm using outputs from three GCMs. Our preliminary result suggests shifts in seasonality and magnitude of cholera over next century in Bengal Delta.