Objective To investigate and analyze the source of infection in an outbreak of gastroenteritis in a kindergarten of Xinjiang Production and Construction Corps, and to provide a reference for formulating targeted epidemic prevention and control strategies.

Methods Cases were identified through face-to-face interviews, telephone follow-ups, and by reviewing kindergarten attendance records, medical institution outpatient logs, and admission/discharge registers. Fecal samples, vomitus, anal swabs, food samples, leftover ingredients, and environmental samples from cafeteria and classrooms were collected. These samples were simultaneously screened for norovirus using real-time fluorescent reverse transcription polymerase chain reaction (RT-PCR) and for enteric pathogens such as Salmonella, diarrheagenic Escherichia coli, and Staphylococcus aureus using real-time fluorescent quantitative PCR.

Results From May 7 to 10, 2024, a total of 114 children (64 boys and 50 girls) were enrolled in the kindergarten, including 26 children in the younger class. A total of 15 norovirus cases were identified, all from the younger class, resulting in an overall attack rate of 13.16% (15/114). The main clinical symptoms included vomiting (93.33%), diarrhea (80.00%), fever (20.00%), and abdominal pain (6.67%). The male-to-female case ratio was 1.5∶1, with most cases occurring among the 4-year-old age group, accounting for 73.33% (11/15) of all cases. The outbreak lasted 63.67 h. A total of 42 samples were collected, including 13 clinical specimens (5 vomit samples, 7 fecal samples, and 1 anal swab), 4 food samples and leftover ingredients from the 48-hour food retention period, 5 environmental samples from the cafeteria, and 20 environmental samples from the younger class classroom (3 storage boxes, 2 bedding sets, 4 LEGO walls, 3 watercolor pens, 4 toy cabinets, 3 cup-swab samples, and 1 tap water sample from the direct drinking water dispenser). RT-PCR results showed a positivity rate of 53.85% (7/13) among patient specimens, with 5 cases testing positive for norovirus GⅡ genotype. The positivity rates for vomitus and fecal samples were 40.00% (2/5) and 71.43% (5/7), respectively. Norovirus GⅡ genotype was detected in 5 of 20 environmental samples from the younger class classroom, yielding a positivity rate of 25.00% (5/20). However, all food, drinking water, and cafeteria environmental samples were negative.

Conclusion This incident is an outbreak and cluster of infections caused by norovirus GⅡ in a kindergarten and the critical factor is that the index case entered the kindergarten while ill. It is necessary to strengthen health education, enhance the disease prevention awareness of teachers, students and parents, develop good hygiene habits, and achieve early detection, reporting, and timely control of such incidents.