A case-control study to assess risk factors related to cholera outbreak in Addis Ababa, Ethiopia, July 2016

Introduction: suspected cholera cases were reported to the city administration health bureau in Addis-Ababa, Ethiopia on June 5, 2016 and it was laboratory confirmed by culture on 7 June 2016. The outbreak was declared by the government on June 8, 2016. The aim of this study was to rapidly investigate the outbreak epidemiologically and guide response activities in the affected Sub cities of Addis Ababa city administration. Methods: an unmatched 1:2 case-control study was conducted in six selected sub-cities of the city administration. Different laboratory tests were also done from suspected possible risk factors identified to support the epidemiological findings. A case was a patient greater than 5 years old, who developed acute watery diarrhea with or without Vomiting. Control was an individual greater than 5 years' old who stayed in the same township and did not suffer from cholera. A structured questionnaire was used to select cases and controls. Epi Info (TM) statistical software was used to analyze the data. Results were presented in narratives, figures and tables. Results: the present study found that, the study participants who used street-vended water (Odds Ratio (OR)=10.4; 95% CI: 1.20-90.9), those who reported holy water sources use (OR=2.7, 95% CI: 1.45-5.04), eating raw meat (OR=7.75; 95% CI: 3.86-15.54) or roasted meat (OR=2.16; 95% CI: 1.19-3.93) and vegetable salad (OR=2.07; 95% CI: 1.14-3.76) were associated with contracting cholera infection. The likelihood of contracting cholera was significantly higher among those who ate food from street vendor sources (OR=5.32; 95% CI: 1.82-15.56) and those who practiced open defecation (OR=8.12; 95% CI (2.20-29.81). Having a latrine (OR=0.29; 95% CI: 0.12-0.69) and proper hand hygiene practice (OR=0.22; 95% CI: 0.14-0.38) were found to be protective against cholera infection. Conclusion: improving awareness of the community by intensifying social mobilization activities through community participation in proper hygienic practice, proper waste disposal and latrine facility construction and utilization. Provision of safe water for the community by strictly conducting end-point assessment of water points and conducting a KAP assessment among food handlers to explore their knowledge and practices regarding safe food/drink handling and water treatment as well as initiate appropriate PH actions based on the findings which will be necessary for prevention of similar cholera outbreaks in the future.