Epidemiological features of the cholera epidemic in Yemen, 2016-2017

Abstract

Background: Cholera was believed to be under control in Yemen, till the eruption of full-fledged civil war and foreign interventions in 2015. Since then, the country experienced by a major epidemic, the largest in more than a century. This thesis presents the characteristics of the epidemic in the first two waves spanning the period from October 2016 to October 2017. Objective: To describe the epidemiological characteristics of cholera incident cases and case-fatality, and to evaluate the overall quality of the control measures and gaps in surveillance within the context of the current violence. Methods: All cases and deaths reported to the Yemen Ministry of Public Healthand Population (MOPHandP) sources were retrospectively described geographically, historically and demographically (age and gender). The clinical and laboratory characteristics of reported cholera cases were also tabulated. Finally, variable-specific rates of incomplete reporting in records at the MOPHandP were studied. Results: There were 901,191 cases reported until the end of the observation period, from twenty-twoYemenis governorates, especially in two peak outbreak waves (October 2016 n= 26028, and April 2017 n= 875163), a peak of cholera cases was observed during the epidemiological week 26 (June). Subsequently, the weekly number of cases decreased, until epidemiological week 36 (September). Of the case-load, 50percent were males and the mean age was19 years. Eight governorates in the northern part of Yemen reported more than 73percent of cholera suspected cases. In particular, Al-Hudaidah and Hajjah governorates reported 14.5percent and 10.9percent of cholera cases respectively. The overall case fatality rate was 0.26 percent. (1st wave CFR=0.46percentand 2nd wave = 0.25percent). Outbreak case-loads continued decreasing trend, starting from week 37, with a shortage of Vibrio laboratory culture results (0.7percent), 0.2percent tested positive for V. cholerae, 1.3percent cases tested by RDTs, 1.0percent tested positive. The classical cholera clinical presentation (AWD) was present in 93percent of cases.