a1 Duke Global Health Institute, Durham, North Carolina USA
a2 Department of Medicine, Duke University Medical Center, Durham, North Carolina USA
a3 Department of Biostatistics and Bioinformatics, Duke University Medical Center, Durham, North Carolina USA
a4 Department of Infectious Diseases and Geographic Medicine, Duke University Medical Center, Durham, North Carolina USA
Introduction Large earthquakes can cause population displacement, critical sanitation infrastructure damage, and increased threats to water resources, potentially predisposing populations to waterborne disease epidemics such as cholera.
Problem The risk of cholera outbreaks after earthquake disasters remains uncertain. A cross-country analysis of World Health Organization (WHO) cholera data that would contribute to this discussion has yet to be published.
Methods A cross-country longitudinal analysis was conducted among 63 low- and middle-income countries from 1995-2009. The association between earthquake disasters of various effect sizes and a relative spike in cholera rates for a given country was assessed utilizing fixed-effects logistic regression and adjusting for gross domestic product per capita, water and sanitation level, flooding events, percent urbanization, and under-five child mortality. Also, the association between large earthquakes and cholera rate increases of various degrees was assessed.
Results Forty-eight of the 63 countries had at least one year with reported cholera infections during the 15-year study period. Thirty-six of these 48 countries had at least one earthquake disaster. In adjusted analyses, country-years with ≥10,000 persons affected by an earthquake had 2.26 times increased odds (95 CI, 0.89-5.72, P = .08) of having a greater than average cholera rate that year compared to country-years having <10,000 individuals affected by an earthquake. The association between large earthquake disasters and cholera infections appeared to weaken as higher levels of cholera rate increases were tested.
Conclusion A trend of increased risk of greater than average cholera rates when more people were affected by an earthquake in a country-year was noted. However these findings did not reach statistical significance at traditional levels and may be due to chance. Frequent large-scale cholera outbreaks after earthquake disasters appeared to be relatively uncommon.
S Sumner, E Turner, N Thielman. Association between earthquake events and cholera outbreaks: a cross-country 15-year longitudinal analysis. Prehosp Disaster Med. 2013;28(6):1-6 .
(Received January 18 2013)
(Revised May 07 2013)
(Accepted June 03 2013)
(Online publication October 29 2013)
Conflicts of interest: The authors have no disclosures or conflicts of interest to report.