Abstract. In 2008, a cholera outbreak with unusually high mortality occurred in western Kenya during civil unrest after disputed presidential elections. Through active case finding, we found a 200% increase in fatal cases and a 37% increase in surviving cases over passively reported cases; the case-fatality ratio increased from 5.5% to 11.4%. In conditional logistic regression of a matched case-control study of fatal versus non-fatal cholera infection, home antibiotic treatment (odds ratio [OR] 0.049; 95% CI: < 0.001-0.43), hospitalization (OR, 0.066; 95% CI, 0.001-0.54), treatment in government-operated health facilities (OR, 0.15; 95% CI, 0.015-0.73), and receiving education about cholera by health workers (OR, 0.19; 95% CI, 0.018-0.96) were protective against death. Among 13 hospitalized fatal cases, chart review showed inadequate intravenous and oral hydration and substantial staff and supply shortages at the time of admission. Cholera mortality was under-reported and very high, in part because of factors exacerbated by widespread post-election violence.

IntroductionKenya experienced widespread cholera outbreaks in 1997-1999 and 2007-2010. The re-emergence of cholera in Kenya in 2015 indicates that cholera remains a public health threat. Understanding past outbreaks is important for preventing future outbreaks. This study investigated the relationship between cholera occurrence in Kenya and various environmental and demographic factors related to water, sanitation, socio-economic status, education, urbanization and availability of health facilities during the time period 2008-2013.MethodsThe primary outcome analyzed was the number of cholera cases at the district level, obtained from the Kenya Ministry of Health's national cholera surveillance records. Values of independent variables were obtained from the 2009 Kenya Population and Housing Census and other national surveys. The data were analyzed using a zero-inflated negative binomial regression model.ResultsMultivariate analysis indicated that the risk of cholera was associated with open defecation, use of unimproved water sources, poverty headcount ratio and the number of health facilities per 100,000 population (p < 0.05). No statistically significant association was found between cholera occurrence and education, percentage of population living in urban areas or population density.ConclusionThe Sustainable Development Goals and Kenya's blueprint for development, Kenya Vision 2030, call for access to sanitation facilities and clean water for all by 2030. Kenya has made important economic strides in recent years but continues to be affected by diseases like cholera that are associated with low socio-economic status. Further expansion of access to sanitation facilities and clean water is necessary for preventing cholera in Kenya.