Abstract
BackgroundNoroviruses (NoVs) are considered an important cause of acute gastroenteritis (AGE) across all age groups, especially in children under 5 years of age. We investigated the epidemiology of noroviruses in outpatient children from the Children’s Hospital of Fudan University in Shanghai, China.MethodsStool specimens were collected between January 2012 and December 2017 from 1433 children under 5 years of age with acute gastroenteritis. All samples were analysed by conventional reverse transcription-polymerase chain reaction (RT-PCR) for genogroup II NoVs amplifying both the RNA-dependent RNA polymerase (RdRp) and partial capsid genes. The Norovirus Genotyping Tool v.2.0 (https://www.rivm.nl/mpf/typingtool/norovirus/) was used for genotyping the strains, and phylogenetic analyses were conducted by MEGA 6.0.ResultsFrom 2012 to 2017, GII NoVs were detected in 15.4% (220/1433) of the samples, with the highest detection rate in children aged 7–12 months (19.2%, 143/746). The seasons with the highest prevalence of GII NoVs infection were autumn and winter. Based on genetic analysis of RdRp, GII.Pe (74.5%%, 137/184) was the most predominant RdRp genotype from 2013 to 2017, while GII.P4 played a dominant role in 2012 (55.6%, 21/36). Among the capsid genotypes, the most prevalent NoV genotype from 2012 to 2017 was GII.4 (74.1%, 163/220). On the basis of genetic analysis of RdRp and capsid sequences, the strains were clustered into − 19 RdRp/capsid genotypes, and 12 of them were discordant, such as GII.Pe/GII.4-Sydney_2012, GII.P12/GII.3, GII.P7/GII.6, GII.Pe/GII.3, and GII.P16/GII.2. Starting with 2013, GII.Pe/GII.4-Sydney_2012 had completely replaced the pandemic GII.P4-2006b/GII.4-2006b subtype and was detected in children across all age groups.ConclusionsThe present study shows high detection rates and the genetic diversity of circulating NoV GII genotypes in paediatric AGE samples from Shanghai. The findings emphasize the importance of continuous molecular surveillance of emerging NoV strains.
Highlights
Noroviruses (NoVs) are considered an important cause of acute gastroenteritis (AGE) across all age groups, especially in children under 5 years of age
GII NoVs can be subdivided into 29 genotypes or 23 genotypes based on the genetic diversity of ORF1 or ORF2, respectively [8, 9]
Acute gastroenteritis is defined as ≥3 instances of loose stool or looser-than-normal stool within a 24-h period combined with significant changes in the faecal exterior, including a watery or thin paste texture and the presence of mucous; this definition excluded the presence of pus or blood regardless of the presence of fever [20]
Summary
Noroviruses (NoVs) are considered an important cause of acute gastroenteritis (AGE) across all age groups, especially in children under 5 years of age. Noroviruses are considered the second most common viral cause of acute gastroenteritis in children [2,3,4,5]. NoVs are highly diverse and divided into seven genogroups (GIGVII), of which GI, GII and GIV have been found in humans, and GII is the most prevalent genogroup in children with acute diarrhoea. Taking into account the phylogenetic relationships of both partial ORF1 and ORF2 sequences, a dual nomenclature system for NoVs has been proposed. This dual typing approach can correctly identify genetically different NoV genotypes. Combinant genotypes are better for understanding the molecular epidemiology of NoVs
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
