Novel hepacivirus in Asian house shrew, China

Dear Editor,Hepatitis C virus (HCV) is a leading global cause of various liver diseases, including chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma. The genome of HCV is monopartite, single-stranded, positive RNA, about 10 kb in size.HCV is the prototype species of the Hepacivirus genus,which contains 14 species according to the update from the International Committee on Taxonomy of Viruses (Smith et al., 2016).

Identification and genetic characterization of bovine hepacivirus in China:A large scale epidemiological study

Bovine hepacivirus(BovHepV)is a novel virus that was recently discovered in Ghana and Germany in 2015.Until now,this virus has been identified in cattle population worldwide and is classified into subtypes A-G.To fully understand the epidemic situation and genetic characteristic of BovHepV in China,a total of 612 cattle serum samples were collected from 20 farms in seven provinces and municipality in China between 2018 and 2020 and were tested for the presence of BovHepV RNA via semi-nested PCR.The results demonstrated that 49(8.0%)samples were BovHepV RNA-positive.It is noted that BovHepV infection in yak was confirmed for the first time.BovHepV was detected in all the seven provinces,with the positive rate ranging from 3.1%to 13.3%,which indicates a wide geographical distribution pattern of BovHepV in China.Sequencing results revealed that 5'UTR of the 49 field BovHepV strains have a nucleotide similarity of 96.3%-100%between each other and 93.9%-100%with previously reported BovHepV strains.In addition,genetic analysis identified five critical nucleotide sites in 5'UTR to distinguish different subtypes,which was further verified by genomic sequencing and nucleotide similarity analysis.All the 49 Chinese field BovHepV strains were classified into subtype G and this subtype is only determined in cattle in China currently.This study will provide insights for us to better understand the epidemiology and genetic diversity of BovHepV.

Distribution and changes in hepatitis C virus genotype in China from 2010 to 2020

BACKGROUND Hepatitis C virus(HCV)causes a large number of infections worldwide.New infections seem to be increasing according to a report of the World Health Organization in 2015.Although direct-acting antivirals are quite effective for most genotypes of the HCV,some genotypes fail to respond.Therefore,the trend of genotype distribution is vital to better control the development of this infection.AIM To analyze the distribution and trends of the HCV genotype before and after the emergence of direct-acting antivirals in China.METHODS We searched all literature published in five electronic databases-China National Knowledge Infrastructure,Wan Fang Data,VIP Chinese Journal Database,Chinese Biomedical Literature Service System,and PubMed-from January 1,2010 to December 31,2020.The search strategy combined medical subject headings and free-text terms,including“hepatitis C virus”or“HCV”and“genotype”or“subtype”and“China”or“Chinese”.Additional relevant articles were searched by manual selection.Data were extracted to build a database.All of the data were totaled according to regions,periods,routes of transmission,and sexes.The percentages in various stratifications were calculated.RESULTS There were 76110 samples from 30 provinces included in the study.Genotype 1(G1)accounted for 58.2%of cases nationwide,followed by G2,G6,G3b,G3a,unclassified and mixed infections(17.5%,7.8%,6.4%,4.9%,1.8%,and 1.2%,respectively).The constitution of genotype varied among different regions,with G6 and G3b being more common in the south and southwest,respectively(28.1%,15.4%).The past ten years have witnessed a decrease in G1 and G2 and an increase in G3 and G6 in almost all regions.The drug-use population had the most abundant genotypes,with G6 ranking first(33.3%),followed by G1 and G3b(23.4%,18.5%).CONCLUSION G3 and G6 pose a new challenge for HCV infection.This study revealed the distribution of HCV genotypes in China over the past 10 years,providing information for HCV management strategies.

Tricistronic hepatitis C virus subgenomic replicon expressing double transgenes

AIM:To construct a tricistronic hepatitis C virus(HCV)replicon with double internal ribosome entry sites(IRESes)of only 22 nucleotides for each,substituting the encephalomyocarditis virus(EMCV)IRESes,which are most often used as the translation initiation element to form HCV replicons.METHODS:The alternative 22-nucleotide IRES,RNA-binding motif protein 3 IRES(Rbm3 IRES),was used to form a tricistronic HCV replicon,to facilitate constructing HCV-harboring stable cell lines andsuccessive antiviral screening using a luciferase marker.Briefly,two sequential Rbm3 IRESes were inserted into bicistronic p UC19-HCV plasmid,consequently forming a tricistronic HCV replicon(p HCV-rep-Neo R-h Rluc),initiating the translation of humanized Renilla luciferase and HCV non-structural gene,along with HCV authentic IRES initiating the translation of neomycin resistance gene.The s H7 cell lines,in which the novel replicon RNA stably replicated,were constructed by neomycin and luciferase activity screening.The intracellular HCV replicon RNA,expression of inserted foreign genes and HCV non-structural gene,as well as response to anti-HCV agents,were measured in s H7 cells and cells transiently transfected with tricistronic replicon RNA.RESULTS:The intracellular HCV replicon RNA and expression of inserted foreign genes and HCV nonstructural gene in s H7 cells and cells transiently transfected with tricistronic replicon RNA were comparable to those in cells stably or transiently transfected with traditional bicistronic HCV replicons.The average relative light unit in p HCV-rep-Neo R-h Rluc group was approximately 2-fold of those in the p UC19-HCV-h RLuc and Tri-JFH1 groups(1.049×108±2.747×107 vs 5.368×107±1.016×107,P<0.05;1.049×108±2.747×107 vs 5.243×107±1.194×107,P<0.05),suggesting that the translation initiation efficiency of the first Rbm3 IRES in the two sequential IRESes was stronger than the HCV authentic IRES and EMCV IRES.The fold changes of 72 h/4 h relative light units in the p HCV-rep-Neo R-h Rluc and p UC19-HCV-h RLuc groups were similar(159.619±9.083 vs163.536±24.031,P=0.7707),and were both higher than the fold change in the Tri-JFH1 group 159.619±9.083 vs 140.811±9.882,P<0.05;163.536±24.031 vs 140.811±9.882,P<0.05),suggesting that the replication potency of the Rbm3 IRES tricistronic replicon matched the replication of bicistronic replicon and exceeded the potency of EMCV IRES replicon.Replication of tricistronic replicons was suppressed by ribavirin,simvastatin,atorvastatin,telaprevir and boceprevir.Interferon-alpha 2b could not block replication of the novel replicon RNA in s H7 cells.After interferon stimulation,Mx A m RNA and protein levels were lower in s H7 than in parental cells.CONCLUSION:Tricistronic HCV replicon with double Rbm3 IRESes could be applied to evaluate the replication inhibition efficacy of anti-HCV agents.

黄病毒科的黄病毒和肝炎病毒研究进展

黄病毒科的黄病毒和肝炎病毒可引起许多严重的人类疾病。该文概述了这两类病毒的体外细胞培养系统、病毒蛋白的抗原结构与功能、病毒毒力的分子基础。