Epidemiology of norovirus gastroenteritis outbreaks in Zhejiang province

Objective To analyze the epidemiological characteristics of norovirus gastroenterits outbreaks in Zhejiang province. Methods Field epidemiological surveys were conducted and fluorescence PCR assays were performed to detect the nucleotide of norovirus. Results Ten norovirus gastroenterits outbreaks with 848 cases were reported from 2004 to 2010 in Zhejiang. The attack rate was 5.31%. The outbreaks occurred in schools, detention houses and in rural areas. The outbreaks were mainly reported in winter and spring and the cases mainly occurred during 2nd-3rd days of an outbreak. The main symptoms of norovirus gastroenterits included diarrhea, vomit, bellyache and abdominal discomfort. The disease courses were short for most cases (1-3 days). Sixty seven specimens were detected to be norovirus positive by fluorescence PCR. The barrelled water contaminated by norovirus was the major infectious source of the disease. Conclusion Norovirus was the one of major pathogens of the nonbacterial gastroenterits outbreaks in Zhejiang. Some outbreaks were related with the drinking of the barrelled water contaminated by norovirus. The spread of the disease may be prevented by taking comprehensive control measures including isolated treatment of patients, disinfection and strengthened water/food management.