Cholera outbreak at a city hotel in Kenya, 2017: a retrospective cohort study

Abstract

Background: The Ministry of Health, Kenya (MOH) investigated a report on acute watery diarrhea (AWD) cases at a city hotel to confirm the cause, characterize, and identify associated factors. Methods: A suspected case of cholera was defined as AWD in any person aged >2 years at the hotel from August 31, 2017, to September 6, 2017. We took rectal swabs for laboratory confirmation and summarized the AWD data by person, place, and time. We defined a cohort of hotel staff with those who ate dinner on August 31, 2017, considered exposed and conducted a retrospective cohort study. We calculated attack rates (AR) and risk ratios (RR) with 95% confidence interval. Variables with p<0.1 at bivariate analysis were entered into a multivariate model and those with p<0.05 in the final model considered independently associated with the AWD. Results: <i>Vibrio cholera</i> was isolated from seven (10.1%) out of 69 samples. Line listed 139 cases with a median age of 32 years (Range: 20–58 years) included 127 (91.4%) male and 127 (91.4%) guests. Index case was reported on August 31, 2017, cases peaked at 95 cases on September 3, 2017, and declined to three on September 6, 2017. A total of 30 (81.1%) of 37 hotel staff were exposed with 17 (56.7%) cases. Food specific ARs were: steamed spinach 78.6% and pineapples 26.3%. Spinach (RR: 3.0 (95%CI: 1.76-72.97)) was a risk factor while pineapples (RR: 0.4 (95%CI: 0.01-0.58)) was protective. Conclusion: This was a point source cholera outbreak likely due to eating contaminated spinach.