20d - Enteropathogenic E. coli gastroenteritis outbreak in Agri Province, Turkiye, March 2023
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Background : On 29 March 2023, an early warning alert was received from acute gastroenteritis (AGE) syndromic surveillance system (n=957) in Agri Province, Turkiye. We investigated the outbreak to identify the source, risk factors and recommend control and prevention measures.
Methods : A probable case was defined as a person admitted to Agri Province hospital with symptoms of nausea or vomiting or diarrhoea between 28 March-5 April 2023. We conducted 1:1 unmatched case control study to compare 114 probable cases and their asymptomatic neighbourhood controls calculating crude and adjusted Odds Ratio (OR) with 95% confidence interval (CI). We evaluated stool samples (n=5) via Polymerase Chain Reaction and culture and water samples (n=23) for residual chlorine, chemicals and microbiological parameters.
Results : The crude attack rate was 1.6%. Common symptoms included diarrhoea (89.8%), nausea (78.6%), abdominal pain (76.5%) and vomiting (81.6%). Consumption of tap water (OR=3.3, 95%CI:1.6-6.5), and bottled water (OR=0.4, 95%CI:0.2-0.7) were associated with illness. After controlling for bottled water, consumption of tap water (ORadj:3.5, 95% CI:1.1-11.2) was significantly associated with the illness. The water samples tested positive for Enterococcus spp., Coliform bacteria, Escherichia coli. Enteropathogenic E. coli (EPEC) was isolated from two stool samples. Environmental investigation revealed that there were low levels of free chlorine prior to the outbreak, and both primary chlorination devices and water network were found to be damaged.
Conclusions The primary water source contamination originating as a result of the damaged water network and chlorination devices was identified as the root cause for the outbreak. Super-chlorination was implemented after chlorination devices were repaired. We recommended maintaining spare chlorination devices, regular monitoring of free chlorine levels and quality enhancement of water pipes to mitigate future incidents.