Epidemiological investigation of an outbreak of acute gastroenteritis caused by GⅡ norovirus at a vocational and technical school
ZHANG Hui1, NIAN Yunpeng2,3, LI Hua2,3, ZHANG Leile1, LAN Ning1,2, LI Xiaohu2,4
1. Xi'an Center for Disease Control and Prevention, Xi'an, Shaanxi 710054, China; 2. Training Program for Field Epidemiology of Shaanxi Provincial Center for Disease Control and Prevention, Xi'an, Shaanxi 710054, China; 3. Shaanxi Provincial Center for Disease Control and Prevention, Xi'an, Shaanxi 710054, China; 4. Fuping County Center for Disease Control and Prevention, Fuping, Shaanxi 711700, China
Abstract：Objective To investigate an outbreak of acute gastroenteritis at a vocational and technical school in Shaanxi Province in 2024, ao as to provide the reference for the handling of school outbreaks. Methods The conducted case searches, individual case investigations, and on-site hygienic investigations were established in accordance with the Guidelines on outbreak investigation, prevention and control of Norovirus infection (2015). The potential risk factors were analyzed by case-control study. Anal swab samples from cases and all canteen staff, as well as environmental swab samples were collected to detect common intestinal pathogens. All reserved food samples in canteen were collected to test for common pathogenic bacteria. Results From October 26 to November 5, 2024, a cumulative total of 53 cases were reported, with an attack rate of 1.47%. The main clinical symptoms included vomiting (83.02%), abdominal pain (56.60%), diarrhea (30.19%), and fever (26.42%). The epidemic curve suggested an intermittent common-source outbreak, with no obvious clustering characteristics in terms of the population and spatial distribution of cases. The case-control analysis revealed that having dinner at the rice-with-dishes-on-top stall on the first floor of the canteen on October 28 was a risk factor for illness (OR=11.025, 95%CI: 2.186-55.601). GⅡ norovirus was detected as positive in anal swab samples from 6 cases and 2 asymptomatic infected canteen staff, as well as in 3 environmental swab samples from the rice-with-dishes-on-top stall. The test results for common pathogenic bacteria in the reserved food samples were all negative. Conclusions This outbreak was caused by an acute gastroenteritis epidemic induced by GⅡ norovirus infection, with a transmission pattern consistent with an intermittent homologous outbreak. The possible source of infection was asymptomatic infected canteen staff mainly through foodborne trasmission, and having meals at the rice-with-dishes-on-top stall was the primary risk factor for this outbreak.
张辉, 年云鹏, 李华, 张磊乐, 兰宁, 李小虎. 一起职业技术学校GⅡ型诺如病毒急性胃肠炎暴发疫情调查[J]. 预防医学, 2025, 37(9): 917-921.
ZHANG Hui, NIAN Yunpeng, LI Hua, ZHANG Leile, LAN Ning, LI Xiaohu. Epidemiological investigation of an outbreak of acute gastroenteritis caused by GⅡ norovirus at a vocational and technical school. Preventive Medicine, 2025, 37(9): 917-921.
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