Hydroclimatology and Large-Scale Population Vulnerability to Cholera Outbreaks in the Bengal Delta

In this chapter, we provide a physical understanding based on the regional large-scale environmental and hydroclimatic processes of how the first outbreaks of cholera may be related to low flow discharge of the Ganges, Brahmaputra, and Meghna rivers and subsequent and salinity intrusion during spring. Cholera incidence values in this season are inversely related to streamflow volumes, that is, bigger spring cholera peaks are seen in strong drought years. On the other hand, autumn cholera outbreaks are positively correlated to peak streamflow volumes, that is, bigger autumn peaks are seen in high flood years. Evidence points to large-scale population vulnerability to biannual cholera transmission mechanisms that provide ecological and environmental “conditions” for cholera outbreaks in the Bengal Delta floodplains.