A Scoping Review of Changing Climate and Weather Connections to Waterborne Pathogens in Coastal Environments

Correlation of climate and infectious disease has been noted for millennia and recorded in the writings of Hippocrates. Given recent technological advances in both pathogen detection and monitoring of infectious diseases in a time of climate change, a detailed study of their link is now possible. In the aquatic environment, climate change has had an impact on ocean, estuary, and freshwater ecosystems that coincides with increased frequency of waterborne disease outbreaks. With climate change, elevated water temperature, acidification, alteration of salinity, and deoxygenation have been observed, all of which are conditions that influence microbial pathogen growth and multiplication. This review examines 11 waterborne microbial pathogens and the conditions optimal for their growth and proliferation, namely temperature, pH, salinity, and dissolved oxygen. Our findings suggest environmental thresholds for optimal growth of waterborne microbial pathogens that include a temperature range of ~30°C–37°C, pH ~7–8, salinity ~5–25 ppt, and dissolved oxygen levels indicative of eutrophication and hypoxia, ~2 mg L⁻¹. As conditions optimal for waterborne microbial pathogens become global and more frequent, a predictive capability will be essential to mitigate increased risk of severe outbreaks of waterborne diseases.