An outbreak of norovirus-associated acute gastroenteritis associated with contaminated barrelled water in many schools in Zhejiang, China.
OBJECTIVE
More than 900 students and teachers at many schools in Jiaxing city developed acute gastroenteritis in February 2014. An immediate epidemiological investigation was conducted to identify the pathogen, infection sources and route of transmission.


METHODS
The probable cases and confirmed cases were defined as students or teachers with diarrhoea or vomiting present since the term began in February 2014. An active search was conducted for undiagnosed cases among students and teachers. Details such as demographic characteristics, gastrointestinal symptoms, and drinking water preference and frequency were collected via a uniform epidemiological questionnaire. A case-control study was implemented, and odds ratios (ORs) and 95% confidence intervals were calculated. Rectal swabs from several patients, food handlers and barrelled water factory workers, as well as water and food samples, were collected to test for potential bacteria and viruses.


RESULTS
A total of 924 cases fit the definition of the probable case, including 8 cases of laboratory-confirmed norovirus infection at 13 schools in Jiaxing city between February 12 and February 21, 2014. The case-control study demonstrated that barrelled water was a risk factor (OR: 20.15, 95% CI: 2.59-156.76) and that bottled water and boiled barrelled water were protective factors (OR: 0.31, 95% CI: 0.13-0.70, and OR: 0.36, 95% CI: 0.16-0.77). A total of 11 rectal samples and 8 barrelled water samples were detected as norovirus-positive, and the genotypes of viral strains were the same (GII). The norovirus that contaminated the barrelled water largely came from the asymptomatic workers.


CONCLUSIONS
This acute gastroenteritis outbreak was caused by barrelled water contaminated by norovirus. The outbreak was controlled after stopping the supply of barrelled water. The barrelled water supply in China represents a potential source of acute gastroenteritis outbreaks due to the lack of surveillance and supervision. Therefore, more attention should be paid to this area.
Department of Public Health Surveillance and Advisory, Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, Zhejiang, China.
Xiaopeng
http://orcid.org/0000-0002-6500-8762
X
Shang
Department of Communicable Disease Control and Prevention, The Center for Disease of Jiaxing City, Jiaxing, Zhejiang,China.
Xiaofei
X
Fu
Department of Center Office, The Center for Disease Control and Prevention of Huzhou City, Huzhou, Zhejiang, China.
Peng
P
Zhang
Department of Center Office, The Center for Disease Control and Prevention of Haining County, Jiaxing, Zhejiang, China.
Minyang
M
Sheng
Department of Center Office, The Center for Disease Control and Prevention of Haiyan County, Jiaxing, Zhejiang, China.
Jianqiang
J
Song
Department of Public Health Surveillance and Advisory, Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, Zhejiang, China.
Fan
F
He
Department of Public Health Surveillance and Advisory, Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, Zhejiang, China.
Yinwei
Y
Qiu
Department of Public Health Surveillance and Advisory, Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, Zhejiang, China.
Haocheng
H
Wu
Department of Public Health Surveillance and Advisory, Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, Zhejiang, China.
Qinbao
Q
Lu
Department of Public Health Surveillance and Advisory, Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, Zhejiang, China.
Yan
Y
Feng
Department of Public Health Surveillance and Advisory, Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, Zhejiang, China.
Junfen
J
Lin
Department of Public Health Surveillance and Advisory, Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, Zhejiang, China.
Enfu
E
Chen
Department of Public Health Surveillance and Advisory, Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, Zhejiang, China.
Chengliang
C
Chai
D000293:Adolescent; D000328:Adult; D017250:Caliciviridae Infections / Q000453:epidemiology* / Q000635:transmission* / Q000821:virology; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D002681:China / Q000453:epidemiology; D004196:Disease Outbreaks; D060766:Drinking Water / Q000382:microbiology*; D004784:Environmental Monitoring; D005260:Female; D005759:Gastroenteritis / Q000453:epidemiology* / Q000821:virology; D006801:Humans; D008297:Male; D029322:Norovirus / Q000145:classification / Q000235:genetics; D016017:Odds Ratio; D011159:Population Surveillance; D057188:Workflow; D055815:Young Adult
D060766:Drinking Water