IntroductionThis study, conducted in China prior to RotaTeq’s launch, examined the epidemiological, molecular, and evolutionary features of the G1P[8] genotype RVA in children admitted with diarrhea, to aid in evaluating its efficacy and impact on G1P[8] RVA in China.MethodsData from the Chinese viral diarrhea surveillance network were collected from January 2016 to December 2018. RVA strains identified as the G1P[8] genotype were subjected to whole-genome sequencing. Neutralizing epitope, amino acid selection pressure, and evolution dynamics analyses on VP7 and VP4 were performed using BioEdit v.7.0.9.0 and PyMOL v.2.5.2, four algorithms (MEME, SLAC, FEL, and FUBAR) in the Datamonkey online software, and the MCMC model in BEAST v. 1.10.4, respectively. Phylogenetic and identity features of 11 genes were assessed by DNAStar and MEGA v.7.ResultsResults showed that the detection rate of G1P[8] in China from 2016 to 2018 was generally low with significant seasonality. The whole genome of G1P[8] of four 2016 childhood diarrhea specimens was successfully sequenced. Phylogenetic and neutralizing epitope analysis showed that Rotavin-M1 might have better protection on G1P[8] prevalent in China than Rotarix and RotaTeq. Two conserved N-glycosylation sites on VP7 of Chinese G1P[8] might affect the protective effect of the vaccine. Evolution rate and selection pressure analysis identified the possibility of rapidly evolving and adapting to the new environment introduced by vaccines of G1P[8], whereas positive selection specific to VP4 indicated the potential tendency to select for dominant traits. Identity and phylogeny analysis showed that Chinese G1P[8] from before 2018 was generally stable with possible genetic recombination among local strains.DiscussionThese findings not only are of great significance for predicting the prevalence of G1P [8] in China, but also provide data reference for evaluating rotavirus vaccine efficacy.

OBJECTIVE:To isolate a prevalent G9P[8] group A rotavirus (RVA) (N4006) in China and investigate its genomic and evolutionary characteristics, with the goal of facilitating the development of a new rotavirus vaccine.METHODS:The RVA G9P[8] genotype from a diarrhea sample was passaged in MA104 cells. The virus was evaluated by TEM, polyacrylamide gel electrophoresis, and indirect immunofluorescence assay. The complete genome of virus was obtained by RT-PCR and sequencing. The genomic and evolutionary characteristics of the virus were evaluated by nucleic acid sequence analysis with MEGA ver. 5.0.5 and DNASTAR software. The neutralizing epitopes of VP7 and VP4 (VP5* and VP8*) were analyzed using BioEdit ver. 7.0.9.0 and PyMOL ver. 2.5.2.RESULTS:The RVA N4006 (G9P[8] genotype) was adapted in MA104 cells with a high titer (105.5 PFU/mL). Whole-genome sequence analysis showed N4006 to be a reassortant rotavirus of Wa-like G9P[8] RVA and the NSP4 gene of DS-1-like G2P[4] RVA, with the genotype constellation G9-P[8]-I1-R1-C1-M1-A1-N1-T1-E2-H1 (G9P[8]-E2). Phylogenetic analysis indicated that N4006 had a common ancestor with Japanese G9P[8]-E2 rotavirus. Neutralizing epitope analysis showed that VP7, VP5*, and VP8* of N4006 had low homology with vaccine viruses of the same genotype and marked differences with vaccine viruses of other genotypes.CONCLUSION:The RVA G9P[8] genotype with the G9-P[8]-I1-R1-C1-M1-A1-N1-T1-E2-H1 (G9P[8]-E2) constellation predominates in China and may originate from reassortment between Japanese G9P[8] with Japanese DS-1-like G2P[4] rotaviruses. The antigenic variation of N4006 with the vaccine virus necessitates an evaluation of the effect of the rotavirus vaccine on G9P[8]-E2 genotype rotavirus.

Objective: To isolate a prevalent G9P[8] group A rotavirus (RVA) strain (N4006) in China and investigate its genomic and evolutionary characteristics, with the goal of facilitating the development of a new rotavirus vaccine. Methods: An RVA strain of the G9P[8] genotype from a diarrhea sample was passaged in MA104 cells. The strain was evaluated by SEM, polyacrylamide gel electrophoresis, and indirect immunofluorescence assay. The complete genome of the strain was obtained by RT-PCR and sequencing. The genomic and evolutionary characteristics of the strain were evaluated by nucleic acid sequence analysis with MEGA ver. 5.0.5 and DNASTAR software. The neutralizing epitopes of VP7 and VP4 (VP5* and VP8*) were analyzed using BioEdit ver. 7.0.9.0 and PyMOL ver. 2.5.2. Results: The N4006 strain (G9P[8] genotype) was adapted in MA104 cells with a high titer (10 5.5 PFU/mL). Whole-genome sequence analysis showed N4006 to be a reassortant rotavirus of Wa-like G9P[8] RVA and the NSP4 gene of DS-1-like G2P[4] RVA, with the genotype constellation G9-P[8]-I1-R1-C1-M1-A1-N1-T1-E2-H1 (G9P[8]-E2). Phylogenetic analysis indicated that N4006 had a common ancestor with Japanese G9P[8]-E2 rotavirus strains. Neutralizing epitope analysis showed that VP7, VP5*, and VP8* of N4006 had low homology with vaccine strains of the same genotype and marked differences with vaccine strains of other genotypes. Conclusion: The G9P[8] genotype rotavirus with the G9-P[8]-I1-R1-C1-M1-A1-N1-T1-E2-H1 (G9P[8]-E2) constellation predominates in China and may originate from reassortment between Japanese G9P[8] with Japanese DS-1-like G2P[4] rotaviruses. The antigenic variation of N4006 with the vaccine strain necessitates evaluation of the effect of the rotavirus vaccine on G9P[8]-E2 genotype rotavirus.

Objective:To investigate the sequence characteristics and evolutionary pattern of a strain of G1P[8] genotype group A rotvirus (RVA) SC18511073 in China and to determine the differences between SC18511073 and the antigenic epitopes of RotaTeq? and Rotarix? vaccines.Methods:RT-PCR amplification of 11 segments of SC18511073 was performed using reverse transcription-polymerase chain reaction (RT-PCR), and the typing was conducted by online RVA automatic typing tool. DNAstar5.1 and Mega11.0 software were used to analyze the homology and genetic evolution of the 11 segments.Results:The genotype constellation of SC18511073 is G1P[8]-I1-R1-C1-M1-A1-N1-T1-E2-H1, and NSP4 is the E2 genotype. The VP7 and NSP3 segments of SC18511073 had high homology with the 2018 Sichuan epidemic G1P[8]-E1 strain, and the phylogenetic tree showed that they were located in the same branch. The remaining nine gene segments all had high homology with the G9P[8]-E2 type prevalent in China and were attributed to the same evolutionary branch. SC18511073 differs from RotaTeq? and Rotarix? by a total of 5 amino acid sites on 7-1a and 7-2 of VP7, and differences in the 8-1 and 8-3 regions of VP8 * antigen epitopes. Conclusions:The 2018 RVA strain SC18511073 in China is a rare G1P[8]-E2 type, which is a new strain generated by re-assortment of VP7 and NSP3 segments during the co-infection process of G1P[8]-E1 and G9P[8]-E2 RVA strains. SC18511073 has amino acid site changes in antigenic epitopes on VP7 and VP4 with RotaTeq? and Rotarix?.

Group A rotavirus (RVA) is one of the most important pathogens of non-bacterial acute gastroenteritis in infants and children under 5 years of age, and diarrhea caused by RVA infection poses a huge disease burden to infants and children worldwide. The effectiveness of vaccines is closely related to RVA genotypes; therefore, this paper summarizes the recent progress in molecular typing characteristics of RVA at home and abroad to provide important information on genotypic diversity and a reference for the selection of virulent strain genotypes in current and future vaccine development.