Factors associated with Schistosomiasis outbreak at Omindamba primary school, Omusati region, Namibia: a case-control study, March 2016

INTRODUCTION: On march 2, 2016, the principal of Omindamba primary school in Outapi district notified the Outapi hospital of a cluster of students complaining of dysuria and passing bloody urine. We conducted an investigation to identify the agent, source of infection, and to determine factors associated with the outbreak. METHODS: An unmatched 1:1 case-control study was conducted. A case was defined as any student of Omindamba primary school, who passed bloody urine with or without dysuria or lower abdominal pains from 2(nd)- 4(th) March 2016, during the time of the investigation. A control was a classmate of a case. We collected demographic, clinical and environmental data. RESULTS: 125 cases and 125 controls were enrolled into the study. The mean age for cases was 11.3 years and controls was 11.0 years, with standard deviation of 3.2 years in both cases and controls. The most affected age group was 11-15 years with 63 (50.4%) cases, followed by 6-10 years with 51(40.8%) cases. Schistosoma hematobium was isolated in the urine specimens examined. Swimming in the canal (adjusted OR = 3.58; 95% CI = 1.14-11.2; p-value = 0.03), and using Etaka pond as a source of water (adjusted OR = 1.95; 95% CI = 1.09-3.50, p-value = 0.02) were independent factors associated with contracting schistosomiasis. CONCLUSION: The Schistosomiasis outbreak among the school children was caused by Schistosoma hematobium. Swimming in the canal and using Etaka pond as a source of drinking water were the predictive factors for the infection. A community-based health education on the prevention of Schistosomiasis was implemented.