Epidemiology characteristics of school norovirus gastroenteritis outbreaks in Zhejiang Province

Objective To understand the epidemiological characteristics and trend of norovirus gastroenteritis outbreaks in Zhejiang school,and to suggest the prevention and control priorities. Methods Descriptive epidemiological analysis was conducted on the incidence data of norovirus gastroenteritis outbreaks through the public health emergency surveillance system in Zhejiang from January 2011 to January 2015,and comparison was made with the national data during the same period and the data in Zhejiang from2004 to 2010. Results There were 20 outbreaks of norovirus gastroenteritis outbreaks with 1929 cases during 2011- 2015 in schools of Zhejiang province. The outbreaks almost occurred in primary and senior middle school,involving students aged 15- 19.The sex ratio of male and female was 1. 13∶ 1. Among 20 outbreaks,19 were induced by norovirus GⅡ infections,only 1 was induced by norovirus G I and GⅡ infections. Six outbreaks were caused by contaminated barrelled water,six were caused by tableware pollution,three were caused by close-contact with cases or contaminated items,two were caused by possible contaminated food,and another three for unknown reasons. Conclusion Outbreaks of school norovirus gastroenteritis usually occur during winter and spring in Zhejiang province,and the epidemic of disease was mainly associated with contaminated barrelled water,tableware and food polluted by norovirus.