Epidemiological Description of a Protracted Cholera Outbreak in Hagadera Refugee Camp and the Surrounding Host Community within Fafi Sub County and Garissa County in Kenya during March-September 2019

Abstract

Background
On 27th March 2019, the Hagadera Refugee Camp reported an outbreak of acute watery diarrhea. An investigation was initiated to confirm the causative organism and define the epidemiology of the outbreak to support evidence-based control measures.
Method
A suspected case was a resident of Hagadera Refugee Camp or the surrounding community with a sudden onset of acute watery diarrhea and vomiting between March 27 and September 16, 2019. A probable case was defined as a suspected case with a positive rapid test for Vibrio cholerae; a confirmed case was a probable case with a positive stool culture for V. cholerae. We conducted a systematic case finding by visiting health facilities and villages. We reviewed patient records to identify suspected cholera case patients. We conducted a descriptive epidemiologic study, examining the distribution of the cases. We computed the attack rates by age, sex, and residence. The case fatality rate was calculated as the ratio of the total number of suspected cholera death to the total number of cholera case-patients. We conducted targeted interventions including spraying, handwashing demonstration, distribution of soaps health education and promotion.
Results
We identified 667 suspected cholera cases between March and September 2019 of these, 38% (253/667) had a positive rapid diagnostic test for V. cholerae; 6% (43) were negative and 56%(371) rapid diagnostic test (RDT) were not conducted. Out of the 94 rectal swabs for culture, 71% (64/94) were confirmed to be V. cholera O1 serotype Inaba. The epidemic curve exhibited a continuous common-source outbreak with several peaks. The mean age of the case-patients was 15-years (range: 0.2-70-years). Both males and female had an attack rate of 9/10000 respectively. The highest attack rate was in ≥30-years (14 per 10,000).
Conclusion
This was a continuous common source cholera outbreak caused by V. cholerae 01 serotype Inaba. We recommended strengthening the surveillance system improving early detection and effective response.