Questionnaire-based epidemiological analysis of acute gastroenteritis outbreak among employees of two neighbouring institutions sharing canteen in Prague 2019.

Objectives: On 17th Dec 2019 gastroenteritis outbreak occurred in two Pragues neighbouring institutions. Investigation aimed to describe outbreak, identify etiological agent, vehicle and propose control measures.

Methods: Routine outbreak investigation and retrospective cohort study was done. Data collected via online questionnaire were analysed using descriptive, univariate and stratified analysis.

Results: Of 960 employees, 276 responded (29%). We identified 39 (14%) cases, one tested norovirus positive. Canteen staff didnt report illness. No food item or environmental sample was tested. Sichuan pork served for lunch on 17th Dec was the most likely vehicle of outbreak (odds ratio (OR) 5.02, 95% confidence interval (CI) 1.98-12.64). Eating Sichuan pork and Chinese soup showed OR 31.5, 95% CI 5.0-320.7. Twenty-two (56%) cases can be explained by consumption of these food items.

Conclusions: Epidemiological analytical method provided evidence of likely vehicle. We did not find the source. Control measures were early ensured and outbreak ceased. We emphasise full outbreak investigation using analytical epidemiology, environmental screening and microbiological testing of cases and possibly all kitchen staff.