1.Analysis on epidemiological and etiology characteristics of 34 aggregation epidemics induced by Norovirus infection
CHEN Qixian, XU Shaojian, ZHOU Shiquan, LIU Lizhen, PENG Weijun, LUO Jingwei
Chinese Journal of School Health 2020;41(3):398-400
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.