Field investigation associates norovirus GII outbreak at Chinese university with canteen dining

A field investigation of an acute gastroenteritis outbreak at a university in Jinhua, China, identified 215 cases from December 14 to 24, 2024, with an overall attack rate of 0.48%. Most affected people experienced diarrhea and vomiting. The study authors reported that the epidemic curve was consistent with continuous exposure to a common source followed by secondary transmission, while laboratory testing found norovirus GII in 16 of 66 clinical, environmental and food-handler samples. Four positive samples were sequenced and identified as GII.17; genotypes for the other positive samples, including the sample described as the index case, were not available.

The investigation combined a descriptive description of cases by time, symptoms and location with case–control and retrospective cohort studies examining dining exposures, hygiene behaviors and illness risk. The first-floor canteen in Zone A had the highest reported attack rate, at 1.14%, compared with 0.56% in Zone B and 0.42% in Zone C. The relative risk for Zone A versus Zone C was 2.71 (95% confidence interval, 1.89–3.89). Dining at the Zone A first-floor canteen was the primary food-related risk factor identified in the analysis, with an odds ratio of 18.85 (95% CI, 2.44–145.39). The reported association increased with the number of meals consumed: relative risks were 1.82 for two or three meals and 3.45 for more than three meals. Poor hand hygiene was also associated with illness, with an odds ratio of 14.60.

Of the 66 tested samples, six positive samples came from canteen workers, including two from people without symptoms. Six infected workers continued working through December 20, and four were cashiers who handled takeaway packaging. Investigators also observed improper glove use and inadequate tableware disinfection in the canteen environment. The authors stated that the epidemiological pattern, together with the laboratory and environmental findings, strongly implicated foodborne transmission involving infected canteen staff, followed by person-to-person spread. The investigation did not establish a complete transmission chain, and the positive samples that were not sequenced could not be assigned a genotype.

The study’s findings were based on the supplied published abstract and were reported in BMC Infectious Diseases as accepted research subject to further editing. Its scope was limited to one university outbreak and the available laboratory sequencing results. The investigators proposed staff health monitoring, standardized work practices, hand-hygiene promotion and prompt disinfection as components of outbreak control, but the abstract did not report a controlled evaluation of those measures or their effectiveness.

Subject of Research: Investigation of a university norovirus GII gastroenteritis outbreak and its association with canteen exposures

Article Title: An outbreak of Norovirus GII gastroenteritis in a Chinese university: investigating transmission patterns and implications for public health interventions

Article References: Bai, K., Pang, Z., Wang, J., Lou, M., Wang, Y., Zhang, B., Fang, L., Long, Z., Wu, C., & Zhang, G. (2026). An outbreak of Norovirus GII gastroenteritis in a Chinese university: investigating transmission patterns and implications for public health interventions. BMC Infectious Diseases. https://doi.org/10.1186/s12879-026-14485-y

Image Credits: AI Generated

DOI: 10.1186/s12879-026-14485-y

Keywords: norovirus, gastroenteritis, university outbreak, foodborne transmission, Jinhua, case-control study, retrospective cohort, environmental sampling, norovirus GII.17, public health, outbreak, Chinese