H7N9 subtype avian influenza virus poses a great challenge for poultry industry.Newcastle disease virus(NDV)-vectored H7N9 avian influenza vaccines(NDV_(vec)H7N9)are effective in disease control because they are prote...H7N9 subtype avian influenza virus poses a great challenge for poultry industry.Newcastle disease virus(NDV)-vectored H7N9 avian influenza vaccines(NDV_(vec)H7N9)are effective in disease control because they are protective and allow mass administration.Of note,these vaccines elicit undetectable H7N9-specific hemagglutination-inhibition(HI)but high IgG antibodies in chickens.However,the molecular basis and protective mechanism underlying this particular antibody immunity remain unclear.Herein,immunization with an NDV_(vec)H7N9 induced low anti-H7N9 HI and virus neutralization titers but high levels of hemagglutinin(HA)-binding IgG antibodies in chickens.Three residues(S150,G151 and S152)in HA of H7N9 virus were identified as the dominant epitopes recognized by the NDV_(vec)H7N9 immune serum.Passively transferred NDV_(vec)H7N9 immune serum conferred complete protection against H7N9 virus infection in chickens.The NDV_(vec)H7N9 immune serum can mediate a potent lysis of HA-expressing and H7N9 virus-infected cells and significantly suppress H7N9 virus infectivity.These activities of the serum were significantly impaired after heat-inactivation or treatment with complement inhibitor,suggesting the engagement of the complement system.Moreover,mutations in the 150-SGS-152 sites in HA resulted in significant reductions in cell lysis and virus neutralization mediated by the NDV_(vec)H7N9 immune serum,indicating the requirement of antibody-antigen binding for complement activity.Therefore,antibodies induced by the NDV_(vec)H7N9 can activate antibody-dependent complement-mediated lysis of H7N9 virus-infected cells and complement-mediated neutralization of H7N9 virus.Our findings unveiled a novel role of the complement in protection conferred by the NDV_(vec)H7N9,highlighting a potential benefit of engaging the complement system in H7N9 vaccine design.展开更多
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
H7N9禽流感病毒(AIV)感染人类的情况最先出现在中国,而且具有很高的突变性。2013年首次在人类身上分离出的是低致病性H7N9禽流感病毒,发展到2017年,已经出现高致病性H7N9禽流感病毒,严重威胁动物和人类的生命健康安全,同时,还会对社会...H7N9禽流感病毒(AIV)感染人类的情况最先出现在中国,而且具有很高的突变性。2013年首次在人类身上分离出的是低致病性H7N9禽流感病毒,发展到2017年,已经出现高致病性H7N9禽流感病毒,严重威胁动物和人类的生命健康安全,同时,还会对社会的稳定和经济发展有一定的影响。综述通过NCBI(National Center for Biotechnology Information)和GISAID数据库收集了中国国内2001~2021年共4641条有关H7N9的数据,拟通过流行病学的角度来说明H7N9禽流感病毒在中国的发生、发展以及在时间、空间和种群间的分布情况,同时总结中国对H7N9所引起的大流行所采取的防控措施,以期为后续的疫情防控措施规划提供依据。展开更多
A novel avian influenza A (H7N9) virus was discovered in February 2013 in China and has resulted in more than 100 comfirmed human infections including 26 fatal cases as of May 2, 2013. The situation raises many ur- ...A novel avian influenza A (H7N9) virus was discovered in February 2013 in China and has resulted in more than 100 comfirmed human infections including 26 fatal cases as of May 2, 2013. The situation raises many ur- gent questions and global public health concerns. In this study, epidemiologic characteristics of infected human cases in Jiangsu province were analyzed and risk assessment was undertaken based on the information available. Briefly, it is highly unlikely that a pandemic of human infection with avian influenza A (HTN9) virus will happen in Jiangsu Province in the near future. Iia the end, some measures are recommended to prevent the situation from becoming worse.展开更多
Objective To trace the source of human H7N9 cases in Huai'an and elucidate the genetic characterization of Huai'an strains associated with both humans and birds in live poultry market.Methods An enhanced surveillanc...Objective To trace the source of human H7N9 cases in Huai'an and elucidate the genetic characterization of Huai'an strains associated with both humans and birds in live poultry market.Methods An enhanced surveillance was implemented when the first human H7N9 case was confirmed in Huai'an.Clinical specimens,cloacal swabs,and fecal samples were collected and screened by real-time reverse transcription-polymerase chain reaction(RT-PCR) for H7N9 virus.The positive samples were subjected to further RT-PCR and genome sequencing.The phylodynamic patterns of H7N9 virus within and separated from Huai'an and evolutionary dynamics of the virus were analyzed.Results Six patients with H7N9 infection were previously exposed to live poultry market and presented symptoms such as fever(〉38.0 °C) and headaches.Results of this study support the hypothesis that live poultry markets were the source of human H7N9 exposure.Phylogenetic analysis revealed that all novel H7N9 viruses,including Huai'an strains,could be classified into two distinct clades,A and B.Additionally,the diversified H7N9 virus circulated in live poultry markets in Huai'an.Interestingly,the common ancestors of the Huai'an H7N9 virus existed in January 2012.The mean nucleotide substitution rates for each gene segment of the H7N9 virus were(3.09-7.26)×10-3 substitutions/site per year(95% HPD:1.72×10-3 to 1.16×10-2).Conclusion Overall,the source of exposure of human H7N9 cases in Huai'an was live poultry market,and our study highlights the presence of divergent genetic lineage of H7N9 virus in both humans and poultry specimens in Huai'an.展开更多
Objective:This paper focuses on the multiple detection RT-PCR technology of H5,H7,AND H9 subtype avian influenza viruses and Newcastle disease virus,and points out the specific detection methods and detection procedur...Objective:This paper focuses on the multiple detection RT-PCR technology of H5,H7,AND H9 subtype avian influenza viruses and Newcastle disease virus,and points out the specific detection methods and detection procedures of avian influenza and Newcastle disease virus.Methods:The genes of Newcastle disease virus carrying out the HA gene sequence of H5,H7 and H9 subtype AIV in GenBank were used to establish a strategy for simultaneous detection of three subtypes of avian influenza virus and Newcastle disease virus.Results:The results showed that the program can detect and distinguish H5,H7 and H9 subtype avian influenza viruses and Newcastle disease virus at one time.Conclusion:Multiple RT-PCR detection method has high detection sensitivity and can detect and determine different subtypes of avian influenza virus and Newcastle disease virus quickly and accurately,therefore,it has a crucial role in the detection and control of avian influenza H5,H7 and H9 subtypes and Newcastle disease.展开更多
BACKGROUND: Data on the mechanical ventilation(MV) characteristics and radiologic features for the cases with H7 N9-induced ARDS were still lacking.METHODS: We describe the MV characteristics and radiologic features o...BACKGROUND: Data on the mechanical ventilation(MV) characteristics and radiologic features for the cases with H7 N9-induced ARDS were still lacking.METHODS: We describe the MV characteristics and radiologic features of adult patients with ARDS due to microbiologically confirmed H7 N9 admitted to our ICU over a 3-month period.RESULTS: Eight patients(mean age 57.38±16.75; 5 male) were diagnosed with H7 N9 in the first quarter of 2014. All developed respiratory failure complicated by acute respiratory distress syndrome(ARDS), which required MV in ICU. The baseline APACHE II and SOFA score was 11.77±6.32 and 7.71±3.12. The overall CT scores of the patients was 247.68±34.28 and the range of CT scores was 196.3–294.7. The average MV days was 14.63±6.14, and 4 patients required additional rescue therapies for refractory hypoxemia. Despite these measures, 3 patients died.CONCLUSION: In H7 N9-infected patients with ARDS, low tidal volume strategy was the conventional mode. RM as one of rescue therapies to refractory hypoxemia in these patients with serious architectural distortion and high CT scores, which could cause further lung damage, may induce bad outcomes and requires serious consideration. Prone ventilation may improve mortality, and should be performed at the early stage of the disease, not as a rescue therapy.展开更多
A Objective3 This study was to understand the genetic variation characters of the H9N2 subtype avian influenza virus isolate (A/Chicken/ Hebei/WD/98, abbreviated as WD98) by comparing with other reference strains. I...A Objective3 This study was to understand the genetic variation characters of the H9N2 subtype avian influenza virus isolate (A/Chicken/ Hebei/WD/98, abbreviated as WD98) by comparing with other reference strains. I-Method3 Eight complete genes were amplified by RT-PCR and sequenced. The homology and genetic evolution relationship were analyzed between these sequences and that of the seven reference strains. [Result] The whole genomic sequence of WD98 strain was 91.1% -95.8% homologous to that of seven reference strains tested. This isolate shared the highest homology (95.8%) to D/HK/Y280/97 and the lowest homology (91.1% ) to C/Pak/2/99. The HA cleavage site of the WD98 strain was R-S-S-R G, and the 226th amino acid at receptor-binding site was Gin. [ Condmion] WD98 strain belongs to mildly pathogenic avian in- fluenza virus and may not infect human. The genetic relationship is the closest between A/Chicken/Hebei/wD/98 and A/duck/HongKong/Y280/ 97, both of which belong to the sub-line of A/Chicken/Beijing/1/94 in Eurasian line. And A/Chicken/Hebei/WD/98 and A/Chicken/Beijing/1/94 are genetically distant within the same sub-line.展开更多
Objective To survey avian influenza A viruses(AIVs) in the environment and explore the reasons for the surge in human H7 N9 cases.Methods A total of 1,045 samples were collected from routine surveillance on poultry-re...Objective To survey avian influenza A viruses(AIVs) in the environment and explore the reasons for the surge in human H7 N9 cases.Methods A total of 1,045 samples were collected from routine surveillance on poultry-related environments and 307 samples from human H7 N9 cases-exposed environments in Henan from 2016 to2017. The nucleic acids of influenza A(Flu A), H5, H7, and H9 subtypes were detected by real-time polymerase chain reaction.Results A total of 27 H7 N9 cases were confirmed in Henan from 2016 to 2017, 24 had a history of live poultry exposure, and 15 had H7 N9 virus detected in the related live poultry markets(LPMs). About 96%(264/275) Flu A positive-environmental samples were from LPMs. H9 was the main AIV subtype(10.05%) from routine surveillance sites with only 1 H7-positive sample, whereas 21.17% samples were H7-positive in H7 N9 cases-exposed environments. Samples from H7 N9 cases-exposed LPMs(47.56%)had much higher AIVs positive rates than those from routine surveillance sites(12.34%). The H7+H9 combination of mixed infection was 78.18%(43/55) of H7-positive samples and 41.34%(43/104) of H9-positive samples.Conclusion The contamination status of AIVs in poultry-related environments is closely associated with the incidence of human infection caused by AIVs. Therefore, systematic surveillance of AIVs in LPMs in China is essential for the detection of novel reassortant viruses and their potential for interspecies transmission.展开更多
Objective To investigate the pathogenesis and immunogenicity of H9N2 influenza virus A/Guangzhou/333/99 (a reassortant of G1 and G9 viruses isolated from a female patient in 1999) in a mouse model of infection.Metho...Objective To investigate the pathogenesis and immunogenicity of H9N2 influenza virus A/Guangzhou/333/99 (a reassortant of G1 and G9 viruses isolated from a female patient in 1999) in a mouse model of infection.Methods Mice were infected with increasing virus titers.Viral load in the lungs and trachea was determined by EID50 assay.Pulmonary histopathology was assessed by hematoxylin‐eosin staining.Anti‐HI antibody titers and T‐cell responses to viral HA were determined by ELISPOT and confirmed by flow cytometry.Results Mice presented a mild syndrome after intranasal infection with A/Guangzhou/333/99 (H9N2) influenza virus.Virus was detected in the trachea and lungs of mice harvested on days 3,6,and 9 post‐infection.A T‐cell response to viral HA was detected on day 6 and H9 HA‐specific CD 4+ T‐cells predominated.Seroconversion was detected after 14 days and antibody persisted for at least 28 weeks.Conclusion Our results suggest that H9N2 (A/Guangzhou/333/99) can replicate in the murine respiratory tract without prior adaptation,and both humoral and cell‐mediated immunity play an important role in the immune response.展开更多
In 2013, a human influenza outbreak caused by a novel H7N9 virus occurred in China. Recently, the H7N9 virus acquired multiple basic amino acids at its hemagglutinin(HA) cleavage site, leading to the emergence of a ...In 2013, a human influenza outbreak caused by a novel H7N9 virus occurred in China. Recently, the H7N9 virus acquired multiple basic amino acids at its hemagglutinin(HA) cleavage site, leading to the emergence of a highly pathogenic virus. The development of an effective diagnostic method is imperative for the prevention and control of highly pathogenic H7N9 influenza. Here, we designed and synthesized three pairs of primers based on the nucleotide sequence at the HA cleavage site of the newly emerged highly pathogenic H7N9 influenza virus. One of the primer pairs and the corresponding probe displayed a high level of amplification efficiency on which a real-time RT-PCR method was established. Amplification using this method resulted in a fluorescent signal for only the highly pathogenic H7N9 virus, and not for any of the H1–H15 subtype reference strains, thus demonstrating high specificity. The method detected as low as 39.1 copies of HA-positive plasmid and exhibited similar sensitivity to the virus isolation method using embryonated chicken eggs. Importantly, the real-time RT-PCR method exhibited 100% consistency with the virus isolation method in the diagnosis of field samples. Collectively, our data demonstrate that this real-time RT-PCR assay is a rapid, sensitive and specific method, and the application will greatly aid the surveillance, prevention, and control of highly pathogenic H7N9 influenza viruses.展开更多
To the editor,1.Introduction to new H7N9 bird flu Influenza virus infection is an important group of respiratory infectious disease.Several groups of influenza viruses can cause human infections.However,in the recent ...To the editor,1.Introduction to new H7N9 bird flu Influenza virus infection is an important group of respiratory infectious disease.Several groups of influenza viruses can cause human infections.However,in the recent years,there are many newly emerging influenza infections,which have never been previously seen in human.Crossing species from animal to human lead展开更多
Objective In March 2012, an H7N7 subtype avian influenza virus (AIV) named A/wild goose/Dongting/PC0360/2022 (H7N7) (DT/PC0360) was recovered from a wild goose in East Dongting Lake. We performed whole-genome se...Objective In March 2012, an H7N7 subtype avian influenza virus (AIV) named A/wild goose/Dongting/PC0360/2022 (H7N7) (DT/PC0360) was recovered from a wild goose in East Dongting Lake. We performed whole-genome sequencing of the isolate, and analyzed the phylogenetic and molecular characterization. Methods RNA was extracted from environment samples (including fecal samples from wild bird or domestic ducks, and water samples) for detecting the presence of Influenza A Virus targeting Matrix gene, using realtime RT-PCR assay. The positive samples were performed virus isolation with embryonated eggs. The subtype of the isolates were identified by RT-PCR assay with the HI-HI6 and N1-N9 primer set. The whole-genome sequencing of isolates were performed. Phylogenetic and molecular characterizations of the eight genes of the isolates were analyzed. Results Our results suggested that all the eight gene segments of DT/PC0360 belonged to the Eurasian gene pool, and the HA gene were belonged to distinct sublineage with H7N9 AIV which caused outbreaks in China's Mainland in 2013. The hemagglutinin cleavage site of HA of DT/PC0360 showed characterization of low pathogenic avian influenza virus. Conclusion Strengthening the surveillance of AlVs of wild waterfowl and poultry in this region is vita for our knowledge of the ecology and mechanism of transmission to prevent an influenza pandemic.展开更多
H9 s ubtype avian influenza virus(AIV) and infectious bronchitis virus(IBV) are major pathogens circulating in poultry and have resulted in great economic losses due to respiratory disease and reduced egg producti...H9 s ubtype avian influenza virus(AIV) and infectious bronchitis virus(IBV) are major pathogens circulating in poultry and have resulted in great economic losses due to respiratory disease and reduced egg production. As similar symptoms are elicited by the two pathogens, it is difficult for their differential diagnosis. So far, no reverse transcription-polymerase chain reaction(RT-PCR) assay has been found to differentiate between H9 AIV and IBV in one reaction. Therefore, developing a sensitive and specific method is of importance to simultaneously detect and differentiate H9 AIV and IBV. In this study, a duplex RT-PCR(d RT-PCR) was established. Two primer sets target the hemagglutinin(HA) gene of H9 AIV and the nucleocapsid(N) gene of IBV, respectively. Spec ific PCR products were obtained from all tested H9 AIVs and IBVs belonging to the major clades circulating in China, but not from AIVs of other subtypes or other infectious avian viruses. The sensitivity of the d RT-PCR assay corresponding to H9 AIV, IBV and mixture of H9 AIV and IBV were at a concentration of 1×10^1, 1.5×10^1 and 1.5×10^1 50% egg infective doses(EID_(50)) m L^–1, respectively. The concordance rates between the d RT-PCR and virus isolation were 99.1 and 98.2%, respectively, for detection of samples from H9N2 AIV or IBV infected chickens, while the concordance rate was 99.1% for detection of samples from H9N2 AIV and IBV co-infected chickens. Thus, the d RT-PCR assay reported herein is specific and sensitive, and suitable for the differential diagnosis of clinical infections and survei llance of H9 AIVs and IBVs.展开更多
A digital RT-PCR method for rapid detection of H9 subtype influenza was established by comparing the two methods of digital RT-PCR and real-time quantitative RT-PCR. The sensitivity, specificity and reproducibility of...A digital RT-PCR method for rapid detection of H9 subtype influenza was established by comparing the two methods of digital RT-PCR and real-time quantitative RT-PCR. The sensitivity, specificity and reproducibility of the two methods for H9 were determined by gradient dilution using the same pair of primers and probes. Both methods were able to detect 104 times diluted H9 pathogens, while digital RT-PCR could detect H9 in single droplets, and its sensitivity was higher than real-time quantitative RT-PCR. At the same time, the specificities of both methods were very strong, with no amplification reactions for H3N2, H4N2, H6N2. The reproducibility of the two methods were also good. Digital RT-PCR has a higher sensitivity than real-time quantitative RT-PCR and could play an important role in the rapid detection of H9 subtype influenza virus.展开更多
基金supported by the earmarked fund for China Agriculture Research System(CARS-40)the Key Research and Development Project of Yangzhou(Modern Agriculture),China(YZ2022052)the‘‘High-end Talent Support Program’’of Yangzhou University,China。
文摘H7N9 subtype avian influenza virus poses a great challenge for poultry industry.Newcastle disease virus(NDV)-vectored H7N9 avian influenza vaccines(NDV_(vec)H7N9)are effective in disease control because they are protective and allow mass administration.Of note,these vaccines elicit undetectable H7N9-specific hemagglutination-inhibition(HI)but high IgG antibodies in chickens.However,the molecular basis and protective mechanism underlying this particular antibody immunity remain unclear.Herein,immunization with an NDV_(vec)H7N9 induced low anti-H7N9 HI and virus neutralization titers but high levels of hemagglutinin(HA)-binding IgG antibodies in chickens.Three residues(S150,G151 and S152)in HA of H7N9 virus were identified as the dominant epitopes recognized by the NDV_(vec)H7N9 immune serum.Passively transferred NDV_(vec)H7N9 immune serum conferred complete protection against H7N9 virus infection in chickens.The NDV_(vec)H7N9 immune serum can mediate a potent lysis of HA-expressing and H7N9 virus-infected cells and significantly suppress H7N9 virus infectivity.These activities of the serum were significantly impaired after heat-inactivation or treatment with complement inhibitor,suggesting the engagement of the complement system.Moreover,mutations in the 150-SGS-152 sites in HA resulted in significant reductions in cell lysis and virus neutralization mediated by the NDV_(vec)H7N9 immune serum,indicating the requirement of antibody-antigen binding for complement activity.Therefore,antibodies induced by the NDV_(vec)H7N9 can activate antibody-dependent complement-mediated lysis of H7N9 virus-infected cells and complement-mediated neutralization of H7N9 virus.Our findings unveiled a novel role of the complement in protection conferred by the NDV_(vec)H7N9,highlighting a potential benefit of engaging the complement system in H7N9 vaccine design.
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H7N9禽流感病毒(AIV)感染人类的情况最先出现在中国,而且具有很高的突变性。2013年首次在人类身上分离出的是低致病性H7N9禽流感病毒,发展到2017年,已经出现高致病性H7N9禽流感病毒,严重威胁动物和人类的生命健康安全,同时,还会对社会的稳定和经济发展有一定的影响。综述通过NCBI(National Center for Biotechnology Information)和GISAID数据库收集了中国国内2001~2021年共4641条有关H7N9的数据,拟通过流行病学的角度来说明H7N9禽流感病毒在中国的发生、发展以及在时间、空间和种群间的分布情况,同时总结中国对H7N9所引起的大流行所采取的防控措施,以期为后续的疫情防控措施规划提供依据。
基金supported by the Jiangsu Province Health Development Project with Science and Education (No.ZX201109 and RC2011085)the Research Projects of Jiangsu Preventive Medicine (No.YZ201020)
文摘A novel avian influenza A (H7N9) virus was discovered in February 2013 in China and has resulted in more than 100 comfirmed human infections including 26 fatal cases as of May 2, 2013. The situation raises many ur- gent questions and global public health concerns. In this study, epidemiologic characteristics of infected human cases in Jiangsu province were analyzed and risk assessment was undertaken based on the information available. Briefly, it is highly unlikely that a pandemic of human infection with avian influenza A (HTN9) virus will happen in Jiangsu Province in the near future. Iia the end, some measures are recommended to prevent the situation from becoming worse.
基金supported by grants HAYf201516 from Huai’an Preventive Medicine Associationgrant HAS2015019-3 from Huai’an Scientific Technological Special Project
文摘Objective To trace the source of human H7N9 cases in Huai'an and elucidate the genetic characterization of Huai'an strains associated with both humans and birds in live poultry market.Methods An enhanced surveillance was implemented when the first human H7N9 case was confirmed in Huai'an.Clinical specimens,cloacal swabs,and fecal samples were collected and screened by real-time reverse transcription-polymerase chain reaction(RT-PCR) for H7N9 virus.The positive samples were subjected to further RT-PCR and genome sequencing.The phylodynamic patterns of H7N9 virus within and separated from Huai'an and evolutionary dynamics of the virus were analyzed.Results Six patients with H7N9 infection were previously exposed to live poultry market and presented symptoms such as fever(〉38.0 °C) and headaches.Results of this study support the hypothesis that live poultry markets were the source of human H7N9 exposure.Phylogenetic analysis revealed that all novel H7N9 viruses,including Huai'an strains,could be classified into two distinct clades,A and B.Additionally,the diversified H7N9 virus circulated in live poultry markets in Huai'an.Interestingly,the common ancestors of the Huai'an H7N9 virus existed in January 2012.The mean nucleotide substitution rates for each gene segment of the H7N9 virus were(3.09-7.26)×10-3 substitutions/site per year(95% HPD:1.72×10-3 to 1.16×10-2).Conclusion Overall,the source of exposure of human H7N9 cases in Huai'an was live poultry market,and our study highlights the presence of divergent genetic lineage of H7N9 virus in both humans and poultry specimens in Huai'an.
文摘Objective:This paper focuses on the multiple detection RT-PCR technology of H5,H7,AND H9 subtype avian influenza viruses and Newcastle disease virus,and points out the specific detection methods and detection procedures of avian influenza and Newcastle disease virus.Methods:The genes of Newcastle disease virus carrying out the HA gene sequence of H5,H7 and H9 subtype AIV in GenBank were used to establish a strategy for simultaneous detection of three subtypes of avian influenza virus and Newcastle disease virus.Results:The results showed that the program can detect and distinguish H5,H7 and H9 subtype avian influenza viruses and Newcastle disease virus at one time.Conclusion:Multiple RT-PCR detection method has high detection sensitivity and can detect and determine different subtypes of avian influenza virus and Newcastle disease virus quickly and accurately,therefore,it has a crucial role in the detection and control of avian influenza H5,H7 and H9 subtypes and Newcastle disease.
基金supported by the National Natural Science Foundation of China(grant number 81501654)Natural Science Foundation of Shanghai(grant number 14ZR1433700)
文摘BACKGROUND: Data on the mechanical ventilation(MV) characteristics and radiologic features for the cases with H7 N9-induced ARDS were still lacking.METHODS: We describe the MV characteristics and radiologic features of adult patients with ARDS due to microbiologically confirmed H7 N9 admitted to our ICU over a 3-month period.RESULTS: Eight patients(mean age 57.38±16.75; 5 male) were diagnosed with H7 N9 in the first quarter of 2014. All developed respiratory failure complicated by acute respiratory distress syndrome(ARDS), which required MV in ICU. The baseline APACHE II and SOFA score was 11.77±6.32 and 7.71±3.12. The overall CT scores of the patients was 247.68±34.28 and the range of CT scores was 196.3–294.7. The average MV days was 14.63±6.14, and 4 patients required additional rescue therapies for refractory hypoxemia. Despite these measures, 3 patients died.CONCLUSION: In H7 N9-infected patients with ARDS, low tidal volume strategy was the conventional mode. RM as one of rescue therapies to refractory hypoxemia in these patients with serious architectural distortion and high CT scores, which could cause further lung damage, may induce bad outcomes and requires serious consideration. Prone ventilation may improve mortality, and should be performed at the early stage of the disease, not as a rescue therapy.
基金supported by subproject of National Program on Key Basic Research Project (973 Program )(2005CB523001)
文摘A Objective3 This study was to understand the genetic variation characters of the H9N2 subtype avian influenza virus isolate (A/Chicken/ Hebei/WD/98, abbreviated as WD98) by comparing with other reference strains. I-Method3 Eight complete genes were amplified by RT-PCR and sequenced. The homology and genetic evolution relationship were analyzed between these sequences and that of the seven reference strains. [Result] The whole genomic sequence of WD98 strain was 91.1% -95.8% homologous to that of seven reference strains tested. This isolate shared the highest homology (95.8%) to D/HK/Y280/97 and the lowest homology (91.1% ) to C/Pak/2/99. The HA cleavage site of the WD98 strain was R-S-S-R G, and the 226th amino acid at receptor-binding site was Gin. [ Condmion] WD98 strain belongs to mildly pathogenic avian in- fluenza virus and may not infect human. The genetic relationship is the closest between A/Chicken/Hebei/wD/98 and A/duck/HongKong/Y280/ 97, both of which belong to the sub-line of A/Chicken/Beijing/1/94 in Eurasian line. And A/Chicken/Hebei/WD/98 and A/Chicken/Beijing/1/94 are genetically distant within the same sub-line.
基金supported by Henan Department of Science and Technology Project [182102310235]Henan Medical Science and Technology Research Project [201702269]Henan Natural Science Foundation [182300410384]
文摘Objective To survey avian influenza A viruses(AIVs) in the environment and explore the reasons for the surge in human H7 N9 cases.Methods A total of 1,045 samples were collected from routine surveillance on poultry-related environments and 307 samples from human H7 N9 cases-exposed environments in Henan from 2016 to2017. The nucleic acids of influenza A(Flu A), H5, H7, and H9 subtypes were detected by real-time polymerase chain reaction.Results A total of 27 H7 N9 cases were confirmed in Henan from 2016 to 2017, 24 had a history of live poultry exposure, and 15 had H7 N9 virus detected in the related live poultry markets(LPMs). About 96%(264/275) Flu A positive-environmental samples were from LPMs. H9 was the main AIV subtype(10.05%) from routine surveillance sites with only 1 H7-positive sample, whereas 21.17% samples were H7-positive in H7 N9 cases-exposed environments. Samples from H7 N9 cases-exposed LPMs(47.56%)had much higher AIVs positive rates than those from routine surveillance sites(12.34%). The H7+H9 combination of mixed infection was 78.18%(43/55) of H7-positive samples and 41.34%(43/104) of H9-positive samples.Conclusion The contamination status of AIVs in poultry-related environments is closely associated with the incidence of human infection caused by AIVs. Therefore, systematic surveillance of AIVs in LPMs in China is essential for the detection of novel reassortant viruses and their potential for interspecies transmission.
基金supported by the National Basic Research Program of China (973 program: 2005CB523006)
文摘Objective To investigate the pathogenesis and immunogenicity of H9N2 influenza virus A/Guangzhou/333/99 (a reassortant of G1 and G9 viruses isolated from a female patient in 1999) in a mouse model of infection.Methods Mice were infected with increasing virus titers.Viral load in the lungs and trachea was determined by EID50 assay.Pulmonary histopathology was assessed by hematoxylin‐eosin staining.Anti‐HI antibody titers and T‐cell responses to viral HA were determined by ELISPOT and confirmed by flow cytometry.Results Mice presented a mild syndrome after intranasal infection with A/Guangzhou/333/99 (H9N2) influenza virus.Virus was detected in the trachea and lungs of mice harvested on days 3,6,and 9 post‐infection.A T‐cell response to viral HA was detected on day 6 and H9 HA‐specific CD 4+ T‐cells predominated.Seroconversion was detected after 14 days and antibody persisted for at least 28 weeks.Conclusion Our results suggest that H9N2 (A/Guangzhou/333/99) can replicate in the murine respiratory tract without prior adaptation,and both humoral and cell‐mediated immunity play an important role in the immune response.
基金supported by the National Key R&D Program of China(2016YFD0500800)the International Science&Technology Cooperation Program of China(2014DFR31260)
文摘In 2013, a human influenza outbreak caused by a novel H7N9 virus occurred in China. Recently, the H7N9 virus acquired multiple basic amino acids at its hemagglutinin(HA) cleavage site, leading to the emergence of a highly pathogenic virus. The development of an effective diagnostic method is imperative for the prevention and control of highly pathogenic H7N9 influenza. Here, we designed and synthesized three pairs of primers based on the nucleotide sequence at the HA cleavage site of the newly emerged highly pathogenic H7N9 influenza virus. One of the primer pairs and the corresponding probe displayed a high level of amplification efficiency on which a real-time RT-PCR method was established. Amplification using this method resulted in a fluorescent signal for only the highly pathogenic H7N9 virus, and not for any of the H1–H15 subtype reference strains, thus demonstrating high specificity. The method detected as low as 39.1 copies of HA-positive plasmid and exhibited similar sensitivity to the virus isolation method using embryonated chicken eggs. Importantly, the real-time RT-PCR method exhibited 100% consistency with the virus isolation method in the diagnosis of field samples. Collectively, our data demonstrate that this real-time RT-PCR assay is a rapid, sensitive and specific method, and the application will greatly aid the surveillance, prevention, and control of highly pathogenic H7N9 influenza viruses.
文摘To the editor,1.Introduction to new H7N9 bird flu Influenza virus infection is an important group of respiratory infectious disease.Several groups of influenza viruses can cause human infections.However,in the recent years,there are many newly emerging influenza infections,which have never been previously seen in human.Crossing species from animal to human lead
文摘Objective In March 2012, an H7N7 subtype avian influenza virus (AIV) named A/wild goose/Dongting/PC0360/2022 (H7N7) (DT/PC0360) was recovered from a wild goose in East Dongting Lake. We performed whole-genome sequencing of the isolate, and analyzed the phylogenetic and molecular characterization. Methods RNA was extracted from environment samples (including fecal samples from wild bird or domestic ducks, and water samples) for detecting the presence of Influenza A Virus targeting Matrix gene, using realtime RT-PCR assay. The positive samples were performed virus isolation with embryonated eggs. The subtype of the isolates were identified by RT-PCR assay with the HI-HI6 and N1-N9 primer set. The whole-genome sequencing of isolates were performed. Phylogenetic and molecular characterizations of the eight genes of the isolates were analyzed. Results Our results suggested that all the eight gene segments of DT/PC0360 belonged to the Eurasian gene pool, and the HA gene were belonged to distinct sublineage with H7N9 AIV which caused outbreaks in China's Mainland in 2013. The hemagglutinin cleavage site of HA of DT/PC0360 showed characterization of low pathogenic avian influenza virus. Conclusion Strengthening the surveillance of AlVs of wild waterfowl and poultry in this region is vita for our knowledge of the ecology and mechanism of transmission to prevent an influenza pandemic.
基金supported by the National High-Tech R&D Program of China(2012AA101303)
文摘H9 s ubtype avian influenza virus(AIV) and infectious bronchitis virus(IBV) are major pathogens circulating in poultry and have resulted in great economic losses due to respiratory disease and reduced egg production. As similar symptoms are elicited by the two pathogens, it is difficult for their differential diagnosis. So far, no reverse transcription-polymerase chain reaction(RT-PCR) assay has been found to differentiate between H9 AIV and IBV in one reaction. Therefore, developing a sensitive and specific method is of importance to simultaneously detect and differentiate H9 AIV and IBV. In this study, a duplex RT-PCR(d RT-PCR) was established. Two primer sets target the hemagglutinin(HA) gene of H9 AIV and the nucleocapsid(N) gene of IBV, respectively. Spec ific PCR products were obtained from all tested H9 AIVs and IBVs belonging to the major clades circulating in China, but not from AIVs of other subtypes or other infectious avian viruses. The sensitivity of the d RT-PCR assay corresponding to H9 AIV, IBV and mixture of H9 AIV and IBV were at a concentration of 1×10^1, 1.5×10^1 and 1.5×10^1 50% egg infective doses(EID_(50)) m L^–1, respectively. The concordance rates between the d RT-PCR and virus isolation were 99.1 and 98.2%, respectively, for detection of samples from H9N2 AIV or IBV infected chickens, while the concordance rate was 99.1% for detection of samples from H9N2 AIV and IBV co-infected chickens. Thus, the d RT-PCR assay reported herein is specific and sensitive, and suitable for the differential diagnosis of clinical infections and survei llance of H9 AIVs and IBVs.
文摘A digital RT-PCR method for rapid detection of H9 subtype influenza was established by comparing the two methods of digital RT-PCR and real-time quantitative RT-PCR. The sensitivity, specificity and reproducibility of the two methods for H9 were determined by gradient dilution using the same pair of primers and probes. Both methods were able to detect 104 times diluted H9 pathogens, while digital RT-PCR could detect H9 in single droplets, and its sensitivity was higher than real-time quantitative RT-PCR. At the same time, the specificities of both methods were very strong, with no amplification reactions for H3N2, H4N2, H6N2. The reproducibility of the two methods were also good. Digital RT-PCR has a higher sensitivity than real-time quantitative RT-PCR and could play an important role in the rapid detection of H9 subtype influenza virus.