Background Norovirus has been the leading cause of non-bacterial gastroenteritis outbreaks in China in recent years.On 24 Oct, 2012, a primary school physician reported several students with vomiting and nausea in Jintan city, Jiangsu Province.Methods We defined a suspected case as students and staff in this school with ≥2 of symptoms as following: vomiting, nausea, abdominal pain and diarrhea between Oct 18th and 31st, 2012.A confirmed case was a suspected case with throat swabs, rectal swabs or vomitus Norovirus genogroup Ⅱ positive by RT-PCR.We selected 24 patients and 24 asymptomatic controls matched by gender and class to compare their behaviors of water drinking and personal hygiene.The distribution of cases from the class with most cases was described by illness onset and spatial.27 cases specimens were collected for laboratory test.