Analysis on epidemiological and etiology characteristics of 34 aggregation epidemics induced by Norovirus infection / 中国学校卫生

ABSTRACT

Objective@#To analyze the epidemiological and etiological characteristics of aggregation epidemics of infectious diarrhea induced by norovirus, and to provide the scientific basis for the prevention and control.@*Methods@#A descriptive epidemiological analysis of aggregation epidemics events occurred during 2016-2018 in Longhua District of Shenzhen was carried out, with subtypes identified by real-time fluorescence quantitative PCR, Region B and Region C fragment sequence determination.@*Results@#There were 34 aggregation epidemic events,including 448 cases, the mean attack rate was 18.26%(448/2 454). The median duration of aggregation epidemic was 3 days. The peak season appeared in autumn and winter, and the peak of epidemic emerged from December 2016 to April 2017. About 91.18% (31/34) of the epidemics occurred in schools and child care centers, and among children aged 3-6 years (78.79%, 353/448). The clinical symptoms were mainly nausea and vomiting (95.77%, 408/426) in children and adolescents but diarrhea in adult group (95.45%, 21/22). The differences between vomiting and diarrhea were both statistically significant in the two age groups (χ2=98.89，99.61，P<0.01). 29 cases were transmitted through interpersonal network, of which 21 cases were found to have unregulated treatment of vomit on campus. The detection rate of biological samples was 49.15% (203/413), all of which were G Ⅱ norovirus. The genotype was mainly GⅡ.P16-G Ⅱ.2(n=49)from November 2016 to April 2017.@*Conclusion@#Norovirus can cause large-scale outbreaks in child care centers and schools easily. Early standardized patient isolation and proper management of vomit and diarrhea are the key steps in prevention and control measures.