Investigation of an outbreak of norovirus epidemic in a kindergarten
Objective To analyze the causes and risk factors of infectious diarrhea outbreak in a kindergarten in Hedong District,Tianjin City to provide a reference for effective epidemic control.Methods The clinical symptoms and tricycle distribution of the cases were described by descriptive epidemiological method.Case-control studies were used to analyze the associated risk factors.Samples from cases,canteen staff,and food were collected for pathogenic testing.Results From December 7 to 15,2020,a total of 42 cases(40 children and 2 teachers)were reported,including 19 clinically diagnosed cases and 23 confirmed cases(laboratory-diagnosed cases),with a prevalence rate of 45.65%(42/92),and the clini-cal manifestations were vomiting(97.62%),fever(69.05%)and abdominal pain(61.90%),but no severe cases or deaths were found.There was no significant difference in the incidence rate between men and women(x2=0.08,P>0.05).There was a statistically significant difference in the incidence rate among the classes(Fisher's exact probability method,P<0.05).The risk factor for the spread of the epidemic was the shared-unventilated-music classroom(OR=95.67,95%CI:12.02-761.09).A total of 30 biological samples were collected for norovirus testing,and 23 of them were found to be positive for norovirus G Ⅱ,with a positive rate of 76.67%.A total of 6 food samples were collected for testing of norovirus,Escherichia coli,Staphylococ-cus aureus,and Salmonella,but none of them were detected.Conclusion This outbreak is an outbreak caused by norovirus G Ⅱ infection,and the shared-unventilated-music classroom is the main risk factor.
NorovirusAerosolEpidemic outbreakCase-control study