Molecular Epidemiology of GI.3 Norovirus Outbreaks from Acute Gastroenteritis Surveillance System in Taiwan, 2015–2019

Shu-Chun Chiu,Jih-Hui Lin,Szu-Chieh Hu,Ching-Yi Wu,Ying-Chin Wang,Jia-Kai Hsu

doi:10.1155/2020/4707538

Abstract

Norovirus is the leading cause of food-borne disease outbreaks. We conducted this study to examine the incidence and molecular characteristics of norovirus genogroup I infections from acute gastroenteritis outbreaks in Taiwan. Between January 2015 and June 2019, 2121 acute gastroenteritis clusters were reported to Taiwan CDC, of which 351 (16.5%) clusters were positive for NoV GI, and GI.3 was the most prevalent (36.8%) during the study period. The GI.3 infections were significantly higher than non-GI.3 infections in the age groups of 0–5 and 6–18 years. The phylogenetic analysis of the MCC tree revealed that VP1 genes were divided into 3 groups: the GI.P3-GI.3 strains in Taiwan were genetically close to Japan and the GI.Pd-GI.3 strains were segregated into 2 other groups which were genetically closely related to China. In addition, 7 GI.Pd-GI.3 recombinants were identified circulating in Taiwan between 2018 and 2019, and the prevalence of GI.Pd-GI.3 should be monitored to assess whether this could become the new predominant strains in neighboring Asian countries or other parts of the world. Both GI.P3-GI.3 and GI.Pd-GI.3 strains cocirculate, the recombination among these two lineages occurs frequently, contributing to the genetic diversity and multiple occurrences of different norovirus lineages, and their rapid evolution makes future control more difficult. Continued surveillance and timely interventions are critical to understand the complexity of norovirus gene variation and to monitor the new emerging norovirus strains.

Highlights

Human noroviruses (NoVs) are the main causative agent of nonbacterial acute gastroenteritis [1]. ey are a genetically diverse group of single-stranded positive-sense RNA viruses with 7.7-kb genomes divided into three open reading frames (ORFs)
Surveillance of viral enteric diarrhea in Taiwan is performed by sentinel physicians through the Notifiable Diseases Surveillance System and is based on laboratory detection of virus nucleic acid. is study represents the prevalence, epidemic genotypic diversity, and spatiotemporal dynamics of NoV GI.3 genotype strains in Taiwan from 2015 to 2019
It is seen that the prevalence of NoV GI in Taiwan is higher than previous reports in China, Seoul, and ailand [29,30,31], NoV GI.3 was the most common genotype detected in outbreaks of NoV GI among Taiwanese people, and NoV GI.3 infection mainly occurred in preschool students (0–5 years) and school students (6–18 years) in Taiwan, similar to previous NoV reports from China that NoV outbreaks mainly occurred in kindergartens and primary schools [29, 32]

Summary

Introduction

Human noroviruses (NoVs) are the main causative agent of nonbacterial acute gastroenteritis [1]. ey are a genetically diverse group of single-stranded positive-sense RNA viruses with 7.7-kb genomes divided into three open reading frames (ORFs). Ey are a genetically diverse group of single-stranded positive-sense RNA viruses with 7.7-kb genomes divided into three open reading frames (ORFs). NoVs are highly diverse viruses that can be genetically grouped into 10 genogroups (GI–GX), but only genogroups GI, GII, GIV, GVIII, and GIX can infect humans, with the GII genogroup being the most prevalent [4, 5]. 9, 22, and 2 VP1 genotypes have been recognized in GI, GII, and GIV, respectively [5, 6]. As recombination frequently occurs in the ORF1/ORF2 overlap, genotyping of both RNA-dependent RNA polymerase (RdRp) in ORF1 and VP1 in ORF2 is necessary to establish a recombinant identity to the virus [7, 8]

Methods

Results

Conclusion