The H9N2 subtype of avian influenza virus(AIV)is widely prevalent in poultry and wild birds globally,and has become the predominant subtype circulating in poultry in China.The H9N2 AIV can directly or indirectly(by se...The H9N2 subtype of avian influenza virus(AIV)is widely prevalent in poultry and wild birds globally,and has become the predominant subtype circulating in poultry in China.The H9N2 AIV can directly or indirectly(by serving as a"donor virus")infect humans,posing a significant threat to public health.Currently,there is a lack of in-depth research on the prevalence of H9N2 viruses in Shanxi Province,central China.In this study,we isolated 14 H9N2 AIVs from October 2020 to April 2022 in Shanxi Province,and genetic analysis revealed that these viruses belonged to 7 different genotypes.Our study on animals revealed that the H9N2 strains we identified displayed high transmission efficiency among chicken populations,and exhibited diverse replication abilities within these birds.These viruses could replicate efficiently in the lungs of mice,with one strain also demonstrating the capacity to reproduce in organs like the brain and kidneys.At the cellular level,the replication ability of different H9N2 strains was evaluated using plaque formation assays and multi-step growth curve assays,revealing significant differences in the replication and proliferation efficiency of the various H9N2 viruses at the cellular level.The antigenicity analysis suggested that these isolates could be classified into 2 separate antigenic clusters.Our research provides crucial data to help understand the prevalence and biological characteristics of H9N2 AIVs in central China.It also highlights the necessity of enhancing the surveillance of H9N2 AIVs.展开更多
One influenza H3N2 virus, A/swine/Shandong/3/2005 (Sw/SD/3/2005), was isolated from pigs with respiratory disease on a farm in eastern China. Genetic analysis revealed that Sw/SD/3/2005 was a triple-reassortant virus ...One influenza H3N2 virus, A/swine/Shandong/3/2005 (Sw/SD/3/2005), was isolated from pigs with respiratory disease on a farm in eastern China. Genetic analysis revealed that Sw/SD/3/2005 was a triple-reassortant virus with a PB2 gene from human-like H1N1, NS from classical swine H1N1, and the remaining genes from human-like H3N2 virus. These findings further support the concept that swine can serve as reservoir or mixing vessels of influenza virus strains and maintain genetic and antigenic stability of viruses. Furthermore, we have successfully established a reverse genetics system based on eight plasmids and rescued Sw/SD/3/2005 through cell transfection. HI tests and RT-PCR confirmed that the rescued virus maintained the biological properties of the wild type Sw/SD/3/2005. The successful establishment of the reverse genetics system of Sw/SD/3/2005 will enable us to conduct extensive studies of the molecular evolution of H3N2 influenza viruses in swine.展开更多
H9N2 avian influenza virus（AIV） infection is a major problem in poultry industry worldwide. In this study, molecular characterizations and phylogenetic relationships of hemagglutinin（HA） gene sequences of H9N2 AIV...H9N2 avian influenza virus（AIV） infection is a major problem in poultry industry worldwide. In this study, molecular characterizations and phylogenetic relationships of hemagglutinin（HA） gene sequences of H9N2 AIV of 5 Chinese isolates in 2014 recently available in Gen Bank, 3 widely used vaccine strains, and 52 novel isolates in China from 2013 to 2015 were analyzed. The homology analysis showed that the nucleotide sequences of HA gene of these recent Chinese H9N2 AIV isolates shared homologies from 94.1 to 99.9%. Phylogenetic analysis showed that all isolates belonged to AIV lineage h9.4.2.5. Fifty-six out of the 57 recent Chinese H9N2 AIV isolates had the motifs PSRSSR↓GLF at the cleavage sites within the HA protein, while one isolate PWH01 harbored LSRSSR↓GLF. Remarkably, all of the recent Chinese H9N2 AIV strains had the Q216 L substitution in the receptor binding site, which indicated that they had potential to infect humans. Most of recent Chinese H9N2 AIV isolates lost the potential N-linked glycosylation site at residues 200–202 compared with vaccine strains. This present study demonstrated that AIV lineage h9.4.2.5 was more predominant in China than other lineages as it harbored all the H9N2 AIV isolated between 2013 and 2015. Also we showed the importance of continuous surveillance of emerging H9N2 AIV in China and update of vaccine formulation accordingly in order to prevent and control H9N2 AIV.展开更多
Objective Symptomatic predictors of influenza could assess risks and improve decisions about isolation and outpatient treatment. To develop such predictors, we undertook a prospective analysis of pandemic （HIN1） 200...Objective Symptomatic predictors of influenza could assess risks and improve decisions about isolation and outpatient treatment. To develop such predictors, we undertook a prospective analysis of pandemic （HIN1） 2009 and seasonal influenza （H3N2） in patients attending fever clinics. Methods From 1 May 2009 to 1 January 2010, all adult patients admitted to fever clinics for suspected influenza, confirmed by real time RT-PCR, were enrolled. Predictors of influenza virus infection were selected with logistic regression models. Measures of sensitivity, specificity, positive and negative likelihood ratios （LRs） were calculated to identify the best predictors. Results The clinical features and routine blood test results of influenza （H1N1） 2009 and seasonal influenza were similar. The positive and negative LRs of current US CDC influenza-like illness （ILl） criteria were modest in predicting influenza infection. Our modified clinic predictors improved the ability of the positive and negative LRs to recognize pandemic （HIN1） 2009 and seasonal influenza. The revised criteria are： fever ~ 38 ~C accompanied by at least one of the following--cough, arthralgia or relative iymphopenia. Conclusion Patients with symptoms and signs that meet the new criteria are likely to have influenza and timely antiviral therapy may be appropriate. In addition, physicians should ascertain if influenza is circulating within the community or if there is a contact history of influenza and combine this information with the newly developed criteria to clinically diagnose influenza.展开更多
Objective To analyze the genetic composition of a novel H2N3 virus isolate identified from a duck cage swab in a live poultry market （LPM） in 2009 in Guangdong province of China. Methods PCR-positive specimens were ...Objective To analyze the genetic composition of a novel H2N3 virus isolate identified from a duck cage swab in a live poultry market （LPM） in 2009 in Guangdong province of China. Methods PCR-positive specimens were inoculated into embryonated chicken eggs and subtyped by conventional RT-PCR. All segments of the virus A/environment/Guangdong/2/2009 were sequenced, and phylogenetic trees were constructed and analyzed. Results The genes of this virus belong to Eurasian-lineage avian viruses. The virus is a reassortant with the HA gene from an H2N2 virus and the NA gene from an H5N3 virus. The PB1, PB2, and NP genes were from an H4N6 virus, the PA was from an H3N8 virus, the M gene was from an H1N3 virus, and the NS gene was from an H10N6 virus. Conclusion market. Its A novel avian-origin reassortant H2N3 influenza virus was detected in a live poultry potential impacts and evolution should be closely monitored.展开更多
基金Fundamental Research Program of Shanxi Province,China(202103021224156)National Natural Science Foundation of China(32202788)+5 种基金Special Research Fund of Shanxi Agricultural University for High-level Talents,China(2021XG004)Science and Technology Innovation Program of Shanxi Agricultural University,China(2021BQ78)special fund for Science and Technology Innovation Teams of Shanxi Province,China(202304051001041)?Shanxi Province Excellent Doctoral Work Award-Scientific Research Project,China(SXBYKY2021005,SXBYKY2021063,SXBYKY2022014)the Fund for Shanxi“1331 Project”,China(20211331-13)earmarked fund for Modern Agro-industry Technology Research System of Shanxi Province,China.
文摘The H9N2 subtype of avian influenza virus(AIV)is widely prevalent in poultry and wild birds globally,and has become the predominant subtype circulating in poultry in China.The H9N2 AIV can directly or indirectly(by serving as a"donor virus")infect humans,posing a significant threat to public health.Currently,there is a lack of in-depth research on the prevalence of H9N2 viruses in Shanxi Province,central China.In this study,we isolated 14 H9N2 AIVs from October 2020 to April 2022 in Shanxi Province,and genetic analysis revealed that these viruses belonged to 7 different genotypes.Our study on animals revealed that the H9N2 strains we identified displayed high transmission efficiency among chicken populations,and exhibited diverse replication abilities within these birds.These viruses could replicate efficiently in the lungs of mice,with one strain also demonstrating the capacity to reproduce in organs like the brain and kidneys.At the cellular level,the replication ability of different H9N2 strains was evaluated using plaque formation assays and multi-step growth curve assays,revealing significant differences in the replication and proliferation efficiency of the various H9N2 viruses at the cellular level.The antigenicity analysis suggested that these isolates could be classified into 2 separate antigenic clusters.Our research provides crucial data to help understand the prevalence and biological characteristics of H9N2 AIVs in central China.It also highlights the necessity of enhancing the surveillance of H9N2 AIVs.
文摘One influenza H3N2 virus, A/swine/Shandong/3/2005 (Sw/SD/3/2005), was isolated from pigs with respiratory disease on a farm in eastern China. Genetic analysis revealed that Sw/SD/3/2005 was a triple-reassortant virus with a PB2 gene from human-like H1N1, NS from classical swine H1N1, and the remaining genes from human-like H3N2 virus. These findings further support the concept that swine can serve as reservoir or mixing vessels of influenza virus strains and maintain genetic and antigenic stability of viruses. Furthermore, we have successfully established a reverse genetics system based on eight plasmids and rescued Sw/SD/3/2005 through cell transfection. HI tests and RT-PCR confirmed that the rescued virus maintained the biological properties of the wild type Sw/SD/3/2005. The successful establishment of the reverse genetics system of Sw/SD/3/2005 will enable us to conduct extensive studies of the molecular evolution of H3N2 influenza viruses in swine.
基金supported by the National Modern Agricultural Industry Technology System Project of China(CARS-41)the Science and Technology Plan Project of Guangdong Province,China(2012B020306002 and 2012B091100078)
文摘H9N2 avian influenza virus（AIV） infection is a major problem in poultry industry worldwide. In this study, molecular characterizations and phylogenetic relationships of hemagglutinin（HA） gene sequences of H9N2 AIV of 5 Chinese isolates in 2014 recently available in Gen Bank, 3 widely used vaccine strains, and 52 novel isolates in China from 2013 to 2015 were analyzed. The homology analysis showed that the nucleotide sequences of HA gene of these recent Chinese H9N2 AIV isolates shared homologies from 94.1 to 99.9%. Phylogenetic analysis showed that all isolates belonged to AIV lineage h9.4.2.5. Fifty-six out of the 57 recent Chinese H9N2 AIV isolates had the motifs PSRSSR↓GLF at the cleavage sites within the HA protein, while one isolate PWH01 harbored LSRSSR↓GLF. Remarkably, all of the recent Chinese H9N2 AIV strains had the Q216 L substitution in the receptor binding site, which indicated that they had potential to infect humans. Most of recent Chinese H9N2 AIV isolates lost the potential N-linked glycosylation site at residues 200–202 compared with vaccine strains. This present study demonstrated that AIV lineage h9.4.2.5 was more predominant in China than other lineages as it harbored all the H9N2 AIV isolated between 2013 and 2015. Also we showed the importance of continuous surveillance of emerging H9N2 AIV in China and update of vaccine formulation accordingly in order to prevent and control H9N2 AIV.
基金supported by Chinese National Programs for High Technology Research and Development (863 Program,2008AA02Z416)
文摘Objective Symptomatic predictors of influenza could assess risks and improve decisions about isolation and outpatient treatment. To develop such predictors, we undertook a prospective analysis of pandemic （HIN1） 2009 and seasonal influenza （H3N2） in patients attending fever clinics. Methods From 1 May 2009 to 1 January 2010, all adult patients admitted to fever clinics for suspected influenza, confirmed by real time RT-PCR, were enrolled. Predictors of influenza virus infection were selected with logistic regression models. Measures of sensitivity, specificity, positive and negative likelihood ratios （LRs） were calculated to identify the best predictors. Results The clinical features and routine blood test results of influenza （H1N1） 2009 and seasonal influenza were similar. The positive and negative LRs of current US CDC influenza-like illness （ILl） criteria were modest in predicting influenza infection. Our modified clinic predictors improved the ability of the positive and negative LRs to recognize pandemic （HIN1） 2009 and seasonal influenza. The revised criteria are： fever ~ 38 ~C accompanied by at least one of the following--cough, arthralgia or relative iymphopenia. Conclusion Patients with symptoms and signs that meet the new criteria are likely to have influenza and timely antiviral therapy may be appropriate. In addition, physicians should ascertain if influenza is circulating within the community or if there is a contact history of influenza and combine this information with the newly developed criteria to clinically diagnose influenza.
基金supportsd by a National Basic Research grant(973)(2011CB504704)
文摘Objective To analyze the genetic composition of a novel H2N3 virus isolate identified from a duck cage swab in a live poultry market （LPM） in 2009 in Guangdong province of China. Methods PCR-positive specimens were inoculated into embryonated chicken eggs and subtyped by conventional RT-PCR. All segments of the virus A/environment/Guangdong/2/2009 were sequenced, and phylogenetic trees were constructed and analyzed. Results The genes of this virus belong to Eurasian-lineage avian viruses. The virus is a reassortant with the HA gene from an H2N2 virus and the NA gene from an H5N3 virus. The PB1, PB2, and NP genes were from an H4N6 virus, the PA was from an H3N8 virus, the M gene was from an H1N3 virus, and the NS gene was from an H10N6 virus. Conclusion market. Its A novel avian-origin reassortant H2N3 influenza virus was detected in a live poultry potential impacts and evolution should be closely monitored.
