Age, primary symptoms, and genotype characteristics of norovirus outbreaks in Shanghai schools in 2017

Yuanping Wang,Lifeng Pan,Xuetao Zhao,Weiping Zhu,Lipeng Hao,Caoyi Xue,Qing Liu

doi:10.1038/s41598-018-33724-0

Yuanping Wang, Lifeng Pan + Show 5 more

Open Access

https://doi.org/10.1038/s41598-018-33724-0

Copy DOI

Abstract

Sixty norovirus outbreaks that occurred in Pudong District, Shanghai in 2017 and affected 959 people were summarised. Of the outbreaks, 29 (48.3%), 27 (45.0%), and 4 (6.7%) occurred in kindergartens, primary schools, and middle schools, respectively. Although the total number of outbreaks peaked in March (13/60, 21.7%), outbreaks in kindergartens and primary schools peaked in April (6/29, 20.7%) and March (8/27, 29.6%), respectively. Primary schools had the highest median number of cases per outbreak (19) and the highest proportion of cases (54.6%). The male-to-female case ratio differed among school classifications, with the highest male case ratio (69.2%) occurring in middle schools. Primary symptoms also differed across the school classifications. Molecular virology analysis showed that a single viral strain caused each outbreak at each school. In turn, 50.6, 28.8, and 20.6% of cases were infected by GII.4, GII.2, and GII.17, respectively. Vomiting was seen in 98.2, 97.3, and 88.6% of the subjects infected with noroviruses GII.17, GII.4, and GII.2, respectively, and nausea in 73.6, 43.9, and 39.0%. In conclusion, noroviruses mainly affect primary school and kindergarten students. GII.4, GII.2, and GII.17 are the main epidemic strains in the local area, and the primary symptoms differed by age and genotype.

Highlights

Noroviruses, previously known as Norwalk viruses, form a group of genetically diverse, positive-stranded non-enveloped RNA viruses belonging to the genus Norovirus, family Caliciviridae[1,2]
We summarise 60 norovirus outbreaks that occurred in schools located in the Pudong District in 2017
Real-time reverse-transcription polymerase chain reaction (RT-PCR) was used for the initial sample testing for noroviruses according to the method we described previously[12]

Summary

Introduction

Noroviruses, previously known as Norwalk viruses, form a group of genetically diverse, positive-stranded non-enveloped RNA viruses belonging to the genus Norovirus, family Caliciviridae[1,2]. Their linear RNA genomes contain three open reading frames (ORFs)[3,4]. A systematic review and meta-analysis of data extracted from studies covering 85 outbreaks occurring from 1987 to 2014 showed that Shigella, pathogenic Escherichia coli, and norovirus were the most common pathogens to cause epidemic acute gastroenteritis in China[9]. We summarise 60 norovirus outbreaks that occurred in schools located in the Pudong District in 2017

Methods

Results

Conclusion