Investigation of an infectious diarrhea epidemic caused by norovirus in a school in Xiacheng district, Hangzhou

On 8 March, 2011, several students in a primary school in Xiacheng dsitrict in Hangzhou developed vomiiting, diarrhea, abdominal pain and dizziness. Field epidemiological survey was conducted for these cases. Stool samples from the patients and water samples were collected to detect pathogenic bacteria and nucleic acid of virus causing diarrhea. Six of 7 stool samples were GⅡ type norovirus posiitve, 4 of 6 water samples were GⅡ type norovirus posiitve. The total numbers of colony in 6 water samples and the coli group in 5 water samples exceeded the limits. No pathogenic bacterium was detected in 13 samples. It is concluded that the diarrhea epidemic in school was caused by the contamination of barreled water with norovirus.