Changing predominance of norovirus strains in children with acute gastroenteritis in Shanghai,2018–2021

Norovirus(NoV)is a major pathogen that causes acute gastroenteritis(AGE)in people of all ages,especially in children.In this study,we investigated the molecular epidemiological characteristics of NoV in children with AGE in Shanghai from 2018 to 2021.The overall detection rate of NoV was 11.9%(181/1545),with annual detection rates of 9.4%(36/381),13.6%(29/213),5.8%(13/226)and 14.2%(103/725),respectively.Of note,the prevalence of NoV in 2020 was significantly lower than that in 2018-2019(10.9%,65/594)(P=0.023)and 2021(14.2%,103/725)(P=0.000).The 181 NoV strains identified in this study were classified into the GI group(1.1%,2/181),GII group(98.3%,178/181)and GIX group(0.6%,1/181)according to the VP1 gene.The most common NoV VP1 genotype was GII.4 Sydney_2012(63.5%,115/181),followed by GII.3(19.9%,36/181)and GII.2(9.4%,17/181).For P genotypes,174 strains were sequenced successfully according to the RdRp gene,and the predominant genotype was GII.P16(44.8%,78/174),followed by GII.P31(25.9%,45/174)and GII.P12(21.3%,37/174).Among the 174 cases,GII.4 Sydney_2012[P16](36.8%,64/174)was the dominant genotype,followed by GII.4 Sydney_2012[P31](25.3%,44/174),GII.3[P12](20.1%,35/174)and GII.2[P16](8.0%,14/174).In particular,the dominant genotypes in Shanghai changed from GII.4 Sydney_2012[P31]in 2018-2019 to GII.4 Sydney_2012[P16]in 2020-2021.This is the first report to describe the epidemiological changes in NoV infection before and during the COVID-19 pandemic in Shanghai.These data highlight the importance of continuous surveillance for NoV in children with AGE in Shanghai.

Genetic Analysis of an Emerging GII.P2–GII.2 Norovirus Associated with a 2016 Outbreak of Acute Gastroenteritis in China

Dear Editor,Noroviruses are positive-sense, single-stranded RNA viruses belonging to Caliciviridae and account for more than 50%of all acute gastroenteritis (AGE) outbreaks worldwide and cause an estimated 200,000 deaths per year among children\5 years of age, primarily in developing countries (Hall et al. 2012;Glass et al. 2009). The norovirus genome contains three open reading frames (ORFs).

Two novel bocaparvovirus species identified in wild Himalayan marmots

Bocaparvovirus(BOV) is a genetically diverse group of DNA viruses and a possible cause of respiratory, enteric, and neurological diseases in humans and animals. Here, two highly divergent BOVs(tentatively named as Himalayan marmot BOV,HMBOV1 and HMBOV2) were identified in the livers and feces of wild Himalayan marmots in China, by viral metagenomic analysis. Five of 300 liver samples from Himalayan marmots were positive for HMBOV1 and five of 99 fecal samples from these animals for HMBOV2. Their nearly complete genome sequences are 4,672 and 4,887 nucleotides long, respectively, with a standard genomic organization and containing protein-coding motifs typical for BOVs. Based on their NS1, NP1, and VP1,HMBOV1 and HMBOV2 are most closely related to porcine BOV SX/1-2(approximately 77.0%/50.0%, 50.0%/53.0%, and79.0%/54.0% amino acid identity, respectively). Phylogenetic analysis of these three proteins showed that HMBOV1 and HMBOV2 formed two distinctly independent branches in BOVs. According to these results, HMBOV1 and HMBOV2 are two different novel species in the Bocaparvovirus genus. Their identification expands our knowledge of the genetic diversity and evolution of BOVs. Further studies are needed to investigate their potential pathogenicity and their impact on Himalayan marmots and humans.

Novel Primate Bocaparvovirus Species 3 Identified in Wild Macaca Mulatta in China

Primate bocaparvovirus(BOV) is a possible cause of respiratory disorders and gastroenteritis in humans. However, the diversity and evolution of these viruses remain largely unknown, despite the identification of a growing number of BOVs in non-human primates(NHPs). Here, we report the identification of a novel BOV(provisionally named Macaca mulatta bocaparvovirus [MmBOV]) in the feces of wild Macaca mulatta in China by viral metagenomic analysis. Seven of 400 fecal samples from Macaca mulatta were positive for MmBOV. An almost complete genome sequence of 4,831 nucleotides was obtained, which had genomic organization and protein motifs similar to human bocaviruses(HOBVs), and shared characteristically low G/C content and weak codon usage bias. Sequence analyses of NS1, NP1, and VP1 revealed that Mm BOV was most closely related to HBOV4 of Primate bocaparvovirus 2(approximately 68.4%/70.6%, 73.3%/67.6%, and 70.4%/73.1% nucleotide/amino acid identities, respectively). Additionally, phylogenetic analysis revealed that Mm BOV formed an independent peripheral branch, but clustered closely with those of the Primate bocaparvovirus species in the BOV genus(particularly HBOV4). These data strongly suggest that HBOV4 originated from NHP bocaparvoviruses around 200–300 years ago, and that NHPs may act as HBOV reservoirs. Following the International Committee of Taxonomy for Viruses guidelines, we propose Mm BOV as a new species(tentatively named Primate bocaparvovirus 3) in the genus Bocaparvovirus, which is the first report of a novel species of primate BOV. Our data facilitate future research on the genetic diversity and evolution of primate bocaparvoviruses and highlight the importance of bocaparvovirus surveys in wild NHPs.