Urogenital schistosomiasis outbreak in a basic school, Volta Region, Ghana: a case-control study

Abstract

Introduction: schistosomiasis is a neglected parasitic infection caused by nematode worms. It affects approximately 200 million people globally. Prevalence in Ghana is 23.3%, mostly affecting school children. On November 28^th 2018, the Disease Surveillance Department received reports of increase in occurrence of bloody urine among students of a basic school in the Volta Region. We investigated to identify the agent and source, to determine the magnitude, risk factors and to implement control measures.

Methods: we conducted a case-control study. A suspected case was any student of the school, who has bloody urine with or without: dysuria, itching of the skin, frequent urination or lower abdominal pain from September 2018 to November 2018. A confirmed case was one with laboratory-isolation of Schistosoma ova in appropriate urine sample. We identified cases from the school and hospital records. We collected socio-demographic, clinical and exposure data from cases and controls. Descriptive and inferential analysis were performed to estimate odds ratios at 95% confidence intervals (CI) to determine associations.

Results: of 880 students, 112 suspected cases were identified (attack rate = 12.7%). Mean age of suspected cases was 14-years (standard deviation = ±3.5). Confirmed cases were 76.8%(86/112). Males had twice odds of becoming cases (cOR = 2.3, 95% CI = 1.35-3.96). Fishing (cOR = 7.29, 95% CI = 4.08-13.04) and swimming (aOR = 44.63, 95% CI = 4.73-420.86) were factors significantly associated with infection. Students with previous history of bloody urine had greater odds of being cases (aOR = 47.9, 95% CI = 4.19-546.55).

Conclusion: Schistosoma haematobium was isolated in this outbreak. Fishing and swimming were risky water-related activities. WASH education and mass drug administration with Praziquantel were control measures.