Proc Natl Acad Sci U S A. 2017 Apr 25;114(17):4436-4441. doi: 10.1073/pnas.1617218114. Epub 2017 Apr 10.
El Ni?o and the shifting geography of cholera in Africa.
Moore SM1,2,3, Azman AS1, Zaitchik BF4, Mintz ED5, Brunkard J5, Legros D6, Hill A6, McKay H1, Luquero FJ7,8, Olson D8, Lessler J9.
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Abstract
The El Ni?o Southern Oscillation (ENSO) and other climate patterns can have profound impacts on the occurrence of infectious diseases ranging from dengue to cholera. In Africa, El Ni?o conditions are associated with increased rainfall in East Africa and decreased rainfall in southern Africa, West Africa, and parts of the Sahel. Because of the key role of water supplies in cholera transmission, a relationship between El Ni?o events and cholera incidence is highly plausible, and previous research has shown a link between ENSO patterns and cholera in Bangladesh. However, there is little systematic evidence for this link in Africa. Using high-resolution mapping techniques, we find that the annual geographic distribution of cholera in Africa from 2000 to 2014 changes dramatically, with the burden shifting to continental East Africa-and away from Madagascar and portions of southern, Central, and West Africa-where almost 50,000 additional cases occur during El Ni?o years. Cholera incidence during El Ni?o years was higher in regions of East Africa with increased rainfall, but incidence was also higher in some areas with decreased rainfall, suggesting a complex relationship between rainfall and cholera incidence. Here, we show clear evidence for a shift in the distribution of cholera incidence throughout Africa in El Ni?o years, likely mediated by El Ni?o's impact on local climatic factors. Knowledge of this relationship between cholera and climate patterns coupled with ENSO forecasting could be used to notify countries in Africa when they are likely to see a major shift in their cholera risk.
KEYWORDS:
Bayesian mapping; El Ni?o Southern Oscillation; cholera; climate and health; disease mapping
PMID: 28396423 DOI: 10.1073/pnas.1617218114
https://www.ncbi.nlm.nih.gov/pubmed/28396423
