Cholera and Climate Change: Pursuing Public Health Adaptation Strategies in the Face of Scientific Debate

Abstract

Climate change will affect the prevalence, distribution, and lethality of many diseases, from mosquito-borne diseases like malaria and dengue fever to directly infectious diseases like influenza to water-borne diseases like cholera and cryptosporidia. This Article focuses on one of the current scientific debates surrounding cholera and the implications of that debate for public health-related climate change adaptation strategies.

Since the 1970s, Rita Colwell and her co-researchers have been arguing a local reservoir hypothesis for cholera, emphasizing that river, estuarine, and coastal waters often contain more dormant forms of cholera attached to copepods, a form of zooplankton. Under this hypothesis, climatically driven increases in sea surface temperatures, sea surface levels, and phytoplankton production — such as during El Niño years or because of climate change — can then spur cholera outbreaks in vulnerable coastal communities. As such, the local reservoir hypothesis has immediate implications for climate change public health adaptation strategies.

In November 2017, however, two teams of scientists published genomic research in Science concluding that epidemic and pandemic cholera outbreaks in the Americas and Africa originate from Asia, suggesting that the local reservoir hypothesis needs modification. The two research articles also suggested a very different strategy for dealing with cholera in the Anthropocene — namely, genetic detection and intensely focused control efforts in Asia.

This Article examines in more detail this emerging scientific debate about cholera reservoirs and the ultimate source(s) of cholera outbreaks and epidemics. It then explores the implications of that debate for climate change public health adaptation strategies, suggesting simultaneously that the cholera debate is one concrete example of how identifying the stakes at issue in different climate change adaptation strategies can help communities and nations to choose appropriate adaptation strategies despite scientific uncertainty.

Keywords: Climate Change, Public Health, Adaptation, Uncertainty, Cholera, Bay of Bengal, Local Reservoir, Genomic Studies