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The number of H7N9 bird flu cases was high and the situation was grim in guizhou province in 2017. To understand the molecular characteristics of the hemagglutinin gene (HA) and the risk of human infection with avian influenza virus A(H7N9) in Guizhou Province, 2017. Homology, genetic evolution and pivotal sites related to receptor binding regions, pathogenicity and potential glycosylation of 14 avian influenza viruses A(H7N9) were analyzed by a series of bioinformation softwares. It was cleared that there was 95.9%-100% similarity among 14 strains in nucleotide of the HA gene, and there were 96.8%-97.8% and 96.8%-97.9% similarities with vaccine strains A/Shanghai/2/2013 and A/Anhui/1/2013 recommended by WHO, respectively. Phylogenetic analysis showed that 14 HA genes were directly evolved in the Yangtze River Delta evolution branch, but they could be derived from five diffenrent strains. Then 13 of 14 strains cleavage site sequences of HA protein revealed they were low pathogenic avian influenza viruses, while A/Guizhou-Weining/CSY01/2017 was high pathogenic avian influenza virus. Mutation G186V at the receptor binding sites in the HA was found in all 14 strains, and mutation Q226L in 13 strains besides A/Guizhou-Weining/CSY01/2017. All five potential glycosylation motifs in the HA were conservative.
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Objective@#To investigate the molecular characteristics and tracing of the hemagglutinin (HA) gene, and to analyze the risk of human infection with influenza virus A (H7N9) in Guizhou Province, so that to provide evidence for the prevention and control of highly pathogenic avian influenza A (H7N9).@*Methods@#Nucleic acids of 5 strains of H7N9 including 1 sample of the patient′s nasopharyngeal swab and 4 samples of the live poultry market (LPM) environment were extracted and HA genes were amplified and sequenced. Then the homology, genetic evolution and the pivotal sites related to receptor binding regions, pathogenicity and potential glycosylation of the avian influenza A (H7N9) viruses were analyzed by a series of bioinformatics softwares.@*Results@#Homology analysis revealed that the homologies of nucleotide and amino-acid of the HA gene of H7N9 strains from the patient and LPM in Weining County, Guizhou Province were 99.8% and 99.6%, respectively, while those of 4 strains from LPM were both 100%. The homologies of nucleotide and amino-acid of the HA gene of H7N9 strains were the highest with the strain of A/Guangxi/5/2017 isolated from a Guangxi infected patient (99.7%-99.9% and 99.4%-99.8%, respectively), while those with the strain isolated from LPMs environment at the end of 2016 (A/Environment/Guangdong/C16283222/2016) were 99.0%-99.2% and 98.9%-99.2%, respectively. However, the homologies of nucleotide and amino-acid of the HA gene of H7N9 strains with A/Shanghai/2/2013 recommended by world health organization and the candidate vaccine strain A/Anhui/1/2013 were 96.8%-97.0% and 95.8%-96.2%, respectively. Phylogenetic analysis showed that the 5 strains had the nearest genetic distance to the strain A/Guangxi/5/2017. All the 5 strains cleavage site sequences of HA protein showed mutation of PEVPKRKRTAR↓GLF, and they were highly pathogenic avian influenza viruses mutant strains, which all had mutation of G186V at the receptor binding sites of HA gene, while no Q226L mutation was found. All 5 strains had new mutation of A363S, and new mutations of R56K and I297V were only found in the strain isolated from the patient. Among the five potential glycosylation motifs in the HA, only 421NWT and 493NNT had variation of the position post shift.@*Conclusions@#All the 5 H7N9 strains isolated in Weining County, Guizhou Province are highly pathogenic avian influenza mutative viruses. The current candidate vaccine may not provide a very good protection. The mutations of cleavage site of HA protein, G186V as well as other new mutation sites of HA may enhance the susceptibility and pathogenicity to human beings.
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Objective To understand the molecular characteristics of hemagglutinin (HA) and neuraminidase (NA) as well as the disease risk of influenza virus A H7N9 in Guizhou province.Methods RNAs were extracted and sequenced from HA and NA genes of H7N9 virus strains obtained from 18 cases of human infection with H7N9 virus and 6 environmental swabs in Guizhou province during 2014-2017.Then the variation and the genetic evolution of the virus were analyzed by using a series of bioinformatics software package.Results Homology analysis of HA and NA genes revealed that 2 strains detected during 2014-2015 shared 98.8％-99.2％ and 99.2％ similarities with vaccine strains A/Shanghai/2/2013 and A/Anhui/1/2013 recommended by WHO,respectively.Two strains detected in 2016 and 14 strains detected in 2017 shared 98.2％-99.3％ and 97.6％-98.8％ similarities with vaccine strain A/Hunan/02650/2016,respectively.Other 6 stains detected in 2017 shared 99.1％-99.4％ and 98.9％-99.3％ similarities with strain A/Guangdong/17SF003/2016,respectively.Phylogenetic analysis showed that all the strains were directly evolved in the Yangtze River Delta evolution branch,but they were derived from different small branch.PEVPKRKRTAR ↓ GLF was found in 6 of 24 strains cleavage site sequences of HA protein,indicating the characteristic of highly pathogenic avian influenza virus.Mutations A134V,G186V and Q226L at the receptor binding sites were found in the HA.All the strains had a stalk deletion of 5 amino acid residue "QISNT" in NA protein,and drug resistance mutation R294K occurred in strain A/Guizhou-Danzhai/ 18980/2017.In addition,potential glycosylation motifs mutations NCS42NCT were found in the NA of 9 of 24 strains.Condusions HA and NA genes of avian influenza A (H7N9) virus showed genetic divergence in Guizhou province during 2014-2017.The mutations of key sites might enhance the virulence of the virus,human beings are more susceptible to it.Hence,the risk of infection is increasing.
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Objective To understand the epidemiological characteristics of human infection with avian influenza A (H7N9) virus in China,and provide evidence for the prevention and control of human infection with H7N9 virus.Methods The published incidence data of human infection with H7N9 virus in China from March 2013 to April 2017 were collected.Excel 2007 software was used to perform the analysis.The characteristics of distribution of the disease,exposure history,cluster of the disease were described.Results By the end of April 2017,a total of 1 416 cases of human infection with H7N9 virus were confirmed in China,including 559 deaths,the case fatality rate was 39.5％.In 2016,the case number was lowest (127 cases),with the highest fatality rate (57.5％).The first three provinces with high case numbers were Zhejiang,Guangdong and Jiangsu.The median age of the cases was 55 years and the male to female ratio was 2.3 ∶ 1.Up to 66％ of cases had clear live poultry exposure history before illness onset,31％ of cases had unknown exposure history and only 3％ of the cases had no live poultry exposure history.There were 35 household clusters (5 in 2013,9 in 2014,6 in 2015,5 in 2016,10 in 2017),which involved 72 cases,accounting for 5％ of the total cases.Conclusions The epidemic of human infection with H7N9 virus in China during 2013-2017 had obvious seasonality and spatial distribution.There was limited family clustering.Infection cases were mostly related to poultry contact.
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Objective To understand the molecular characteristics of hemagglutinin (HA) and neuraminidase (NA) as well as the disease risk of influenza virus A H7N9 in Guizhou province.Methods RNAs were extracted and sequenced from HA and NA genes of H7N9 virus strains obtained from 18 cases of human infection with H7N9 virus and 6 environmental swabs in Guizhou province during 2014-2017.Then the variation and the genetic evolution of the virus were analyzed by using a series of bioinformatics software package.Results Homology analysis of HA and NA genes revealed that 2 strains detected during 2014-2015 shared 98.8％-99.2％ and 99.2％ similarities with vaccine strains A/Shanghai/2/2013 and A/Anhui/1/2013 recommended by WHO,respectively.Two strains detected in 2016 and 14 strains detected in 2017 shared 98.2％-99.3％ and 97.6％-98.8％ similarities with vaccine strain A/Hunan/02650/2016,respectively.Other 6 stains detected in 2017 shared 99.1％-99.4％ and 98.9％-99.3％ similarities with strain A/Guangdong/17SF003/2016,respectively.Phylogenetic analysis showed that all the strains were directly evolved in the Yangtze River Delta evolution branch,but they were derived from different small branch.PEVPKRKRTAR ↓ GLF was found in 6 of 24 strains cleavage site sequences of HA protein,indicating the characteristic of highly pathogenic avian influenza virus.Mutations A134V,G186V and Q226L at the receptor binding sites were found in the HA.All the strains had a stalk deletion of 5 amino acid residue "QISNT" in NA protein,and drug resistance mutation R294K occurred in strain A/Guizhou-Danzhai/ 18980/2017.In addition,potential glycosylation motifs mutations NCS42NCT were found in the NA of 9 of 24 strains.Condusions HA and NA genes of avian influenza A (H7N9) virus showed genetic divergence in Guizhou province during 2014-2017.The mutations of key sites might enhance the virulence of the virus,human beings are more susceptible to it.Hence,the risk of infection is increasing.
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Objective To understand the epidemiological characteristics of human infection with avian influenza A (H7N9) virus in China,and provide evidence for the prevention and control of human infection with H7N9 virus.Methods The published incidence data of human infection with H7N9 virus in China from March 2013 to April 2017 were collected.Excel 2007 software was used to perform the analysis.The characteristics of distribution of the disease,exposure history,cluster of the disease were described.Results By the end of April 2017,a total of 1 416 cases of human infection with H7N9 virus were confirmed in China,including 559 deaths,the case fatality rate was 39.5％.In 2016,the case number was lowest (127 cases),with the highest fatality rate (57.5％).The first three provinces with high case numbers were Zhejiang,Guangdong and Jiangsu.The median age of the cases was 55 years and the male to female ratio was 2.3 ∶ 1.Up to 66％ of cases had clear live poultry exposure history before illness onset,31％ of cases had unknown exposure history and only 3％ of the cases had no live poultry exposure history.There were 35 household clusters (5 in 2013,9 in 2014,6 in 2015,5 in 2016,10 in 2017),which involved 72 cases,accounting for 5％ of the total cases.Conclusions The epidemic of human infection with H7N9 virus in China during 2013-2017 had obvious seasonality and spatial distribution.There was limited family clustering.Infection cases were mostly related to poultry contact.
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We analyzed genetic evolution characteristics of avian influenza A (H7N9) virus isolated in Zhaoqing,China,2014-2016.Nucleic acid were extracted and sequenced from 17 samples of H7N9 positive cases in Zhaoqing.Genetic characteristics of homology and important amino acid sites were analyzed by using BioEdit5.0 and MEGA6.0.The evolutionary trees were constructed by Neighbor-Joining and the referenced sequences were downloaded from GenBank,Eight nucleic acid fragments from 7 strains of H7N9 viruses were successfully generated.The highest homology was found in HA gene with A/chicken/Dongguan/695/2014(H7N9),and NA gene with A/chicken/Dongguan/1075/2014(H7N9).The internal genes were high homology with avian H7N9 and H9N2 virus from Dongguan and Shenzhen in Guangdong,China.The HA and NA genes were directly evolved in the Pearl River Delta evolution branch with the H7N9 sequences from the cities of Dongguan,Guangzhou and Shenzhen,while the sequences from the provinces of Anhui,Zhejiang,and Jiangsu were in the Yangtze River Delta evolution branch.There were 2 alkaline amino acids in cleavage site of HA,2 mutations (G186V and Q226L) in the crucial sites related with the receptor of HA protein,1 mutation (E627K) in PB2 protein,and 1 drug resistance mutation (S31N) in M2 protein.And no evidence of neuraminidase resistance in NA protein was found.In conclusion,the H7N9 virus for human infection in Zhaoqing may originate from avian H7N9 and H9N2 viruses,which circulated in the Pearl River Delta region of Guangdong from 2013 to 2014.The mutations of G186V,Q226L and E627 K might be related with high susceptibility to human beings.
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Objective@#To prepare strains of influenza A (H7N9) pseudovirus derived from different districts of China for vaccine efficacy evaluation.@*Methods@#Phylogenetic tree was built based on hemagglutinin (HA) amino acid sequence analyses from 29 influenza A (H7N9) virus strains and 6 influenza A (H7N9) virus strains with HA determinants variation were selected. 293FT cells were co-transfected with plasmid pNL4-3-Luc.R-E-, pVRC-HA and pVRC-NA with codon-optimized hemagglutinin (HA) and neuraminidase (NA) derived from the six influenza A (H7N9) virus strains, respectively. Transmission electron microscopy assay and Western blot analysis were performed to demonstrate morphology and specificity of these particles, luciferase activity assay and hemagglutinin titers detection were used to determine their infectivity and hemagglutinin activity. And finally, pseudovirus-based neutralization assays were evaluated with HA immunized mice serum.@*Results@#Six influenza A (H7N9) peseudovirus particles derived from different districts of China were selected and prepared. All of the particles bearing HA and NA were characterized with classic influenza virus morphology, with TCID50 titer ranged from 104TCID50/50 μl to 105TCID50/50 μl and with hemagglutinin activity ranged from 64 to 512. Neutralization efficacies on influenza A/Shanghai/1/2013(H7N9) HA vaccine serum against 100TCID50 dose of these pseudovirus particles indicated their potential application in the vaccine cross-protective evaluation in future.@*Conclusions@#Six influenza A (H7N9) pseudovirus derived from different districts of China with potential antigenic variation on HA were constructed successfully, established foundation for their further application in vaccine cross-reactive efficacy evaluation.
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Since March 2013,China had experienced five seasonal epidemics related to Avian influenza A (H7N9).An unprecedented outbreak of H7N9 epidemic started from September 2016,with 730 cases reported till June 30th 2017,in mainland China that caused profound influences on both social development and health of the people.As an emerging infectious disease,information on pathogenic characteristics,transmission patterns and other epidemiological features of H7N9 virus somehow remained unclear.Data from previous studies suggested that the live poultry market (LPM) seemed to have served as main places where H7N9 virus got originated,mutated,spread and thus infected the human beings.Hence,closure of LPMs was suggested a major measure to control and prevent H7N9 epidemics in China.However,the effectiveness of different ways of LPM closures on H7N9 epidemics had been controversial.This study systemically summarized the effects of different ways of LPM closures on H7N epidemics from previous studies,aiming to provide references for developing a better program on H7N9 control and prevention in the country.
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Since March 2013,China had experienced five seasonal epidemics related to Avian influenza A (H7N9).An unprecedented outbreak of H7N9 epidemic started from September 2016,with 730 cases reported till June 30th 2017,in mainland China that caused profound influences on both social development and health of the people.As an emerging infectious disease,information on pathogenic characteristics,transmission patterns and other epidemiological features of H7N9 virus somehow remained unclear.Data from previous studies suggested that the live poultry market (LPM) seemed to have served as main places where H7N9 virus got originated,mutated,spread and thus infected the human beings.Hence,closure of LPMs was suggested a major measure to control and prevent H7N9 epidemics in China.However,the effectiveness of different ways of LPM closures on H7N9 epidemics had been controversial.This study systemically summarized the effects of different ways of LPM closures on H7N epidemics from previous studies,aiming to provide references for developing a better program on H7N9 control and prevention in the country.
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Objective To investigate the changes and clinical significance of peripheral blood T lymphocyte subsets and cytokines in influenza A (H7N9) virus infection patients.Methods Twenty-three patients with H7N9 virus infection who received treatment at the First Affiliated Hospital of Soochow University from April 2013 to April 2015 were enrolled as case group.Twenty healthy subjects in the outpatient clinic during the same period were selected as control group.The percentages of T lymphocyte subsets in the peripheral blood including CD3+CD4+ T cells, CD3+CD8+ T cells, regulatory T lymphocytes (Treg), Th17, CD3+CD8-interferon (IFN)-γ+ (Th1) cells and CD3+CD8-IL-4+ (Th2) cells were detected by flow cytometry.The changes of plasma cytokines including interleukin (IL)-8, IL-18, interferon-inducible protein (IP)-10, macrophage inflammatory protein (MIP)-1b were quantified by Bio-Plex Pro human cytokine Group Ⅰ 27-plex panel and Group Ⅱ 21-plex panel.The normality test was performed by Kolmogorov-Smirnov test.Two independent samples t test were used to compare the two groups.Results The percentages of CD3+CD4+ and CD3+CD8+ T cells before treatment in case group were significantly lower than control group ([27.90±10.19]% vs [38.75±6.78]%, t=-2.726, P=0.012;[14.82±7.72]% vs [22.79±6.12]%, t=-2.556, P=0.018), while the percentages of Th17 and Th2 before treatment in case group were significantly higher than control group ([2.64±1.40]% vs [0.29±0.21]%, t=4.668, P0.05).Before treatment, levels of IL-8, IL-18, IP-10 and MIP-1b of case group were significantly higher than those in control group (IL-8: [23.19±14.35] vs [12.78±6.76] ng/L, t=2.277, P=0.035;IL-18:[230.55±230.18] vs [72.80±27.91] ng/L, t=2.348, P=0.036;IP-10:[28 870.55±41 815.22] vs [1 356.13±1 093.10] ng/L, t=2.371, P=0.035;MIP-1b: [197.74±119.87] vs [118.51±41.86] ng/L, t=2.198, P=0.043).Conclusions Patients with H7N9 virus infection exhibit an imbalance of T lymphocyte subsets.It is very important to monitor the changes of T lymphocyte subsets in those patients for clinical prognosis.A storm of cytokines could exist during H7N9 virus infection, which may be the main reason for multiple organ failure.
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To analyze the epidemiological characteristics of human infection with avian influenza A(H7N9) virus from 2013 to 2016 in Xiaoshan,China,we collected the epidemiological data of human A(H7N9) cases as well as the results of environmental monitoring and analyzed it by case study,descriptive epidemiological method,and statistical analysis.Results showed that a total of 22 cases were confirmed,including 12 deaths.All the cases occurred in winter and spring,and most of them had been exposed to live poultry,and with the underlying condition of chronic diseases.Chi-square test showed that the ratio of cases with chronic diseases in death group was higher (P=0.01).The environmental monitoring result showed there were distinctive seasonal differences of positive rate with peaks in winter and spring and nadirs in autumn and summer.Positive rates for the samples from external environmental monitoring were consistent with the distribution of the case onset.Due to rise of environmental monitoring positive rate,we should be alert to the occurrence of new cases,especially in rural areas where live poultry fairs still exist and among people with occupational exposure.We should further improve ability to prevent and control this disease.
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BACKGROUND: In March 2013, human infection with avian influenza A (H7N9) virus emerged in China, causing serious public health concerns and raising the possibility of avian-source pandemic influenza. Thus, the development of an effective vaccine for preventing and rapidly controlling avian influenza A (H7N9) virus is needed. In this study, we evaluated the immunogenicity of a synthetic DNA vaccine against H7 HA antigens in mice. MATERIALS AND METHODS: The synthetic consensus H7 HA DNA vaccine (25 or 50 µg) was administered to BALB/c mice at 0, 14, and 28 days by intramuscular injection followed by electroporation. Humoral and cellular immune responses were analyzed in a hemagglutination inhibition test and interferon-gamma enzyme-linked immunospot (ELISpot) assay, respectively. RESULTS: H7 HA-vaccinated mice showed 100% seroprotection and seroconversion rate against H7N9 reassortant influenza virus after both second and third immunizations. The geometric mean titer by the hemagglutination inhibition test increased with an increasing number of immunizations. However, there was no significant difference in geometric titer between the two groups injected with 25 and 50 µg of H7 HA DNA vaccine after two (79.98 vs. 107.65, P = 0.39) and three (159.96 vs. 215.28, P = 0.18) doses. In addition, the ELISpot assay revealed that administration of H7 HA DNA vaccine induced potent interferon-gamma production from mouse splenocytes. CONCLUSIONS: This study demonstrated the humoral and cellular immunogenicity of synthetic consensus H7 HA DNA vaccine in mice. This work demonstrates the potential of the H7 HA DNA vaccine as an efficient tool for the rapid control of emerging influenza A (H7N9) virus.
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Animals , Humans , Mice , China , Consensus , DNA , Electroporation , Enzyme-Linked Immunospot Assay , Hemagglutination Inhibition Tests , Immunity, Cellular , Immunization , Influenza in Birds , Influenza, Human , Injections, Intramuscular , Interferon-gamma , Orthomyxoviridae , Pandemics , Public Health , SeroconversionABSTRACT
Chinese Center for Disease Control and Prevention published three confirmed novel H 7N9 avain influenza virus in-fection cases on March 31 ,2013 .The disease then spread across China and caused extremely high morbility and mortality , which trig-gered extensive attention .These cases were caused by a novel H 7N9 avian influenza virus which was highly mutable .Once the virus a-dapted to human respiratory epithelium receptors , a pandemic outbreak would occur immediately .This article summerizes the research progress on the H7N9 avain influenza, including epidemiologic characteristics , etiology features, clinical manifestation, detection tech-niques as well as theraputic and prevention strategy .
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Objective TounderstandandevaluatethetransmissionriskofavianinfluenzaA(H7N9)virusinlivepoultry markets(LPMs).Methods Atotalof31LPMsfromJiaxingcitywereselectedusingrandomsamplingmethodand hygienicinvestigationonthespotwascarriedout.Results All31farmproductmarketshadlivepoultrytradewhile29 (83.87%)of them had live poultry slaughter spots,and 3 of them were not in the trade zone.The situation of sanitary, isolation,disinfection and personal protection in live poultry trading spot was not satisfied and only one LPM set a compartment.The LPMs whose distance exceeding 10 meters between live poultry slaughter spot and trading spot were accountedfor41.38%.Conclusion ThetransmissionriskofavianinfluenzaA(H7N9)virusinfarmproductmarketis high.To close the live poultry market during the epidemic period and strengthen surveillance activities are suggested.
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Objective Farmer' s markets with live birds (FMLB) are key sites where human infections by influenza A virus subtype H7N9 happened.Approximately 80％ cases have exposed to FMLB.This study is to investigate the geographic relationship between FMLB and human cases based on analysis of internet data of their geographic locations.Methods Using big data from internet,we searched all FMLB in the cities where the human cases have been reported,then analyzed geographic relations,and evaluated the possibility of visits of the patients to the FMLB around them.The densities of FMLB,population and live poultries were also analyzed.Results Forty-two cities and 10 615 markets were included in the study.It is indicated that the number of human cases has positive correlations with the population density,the number and density of markets.Except three markets in Foshan,human cases have been reported within 5 km of 10 of 13 markets,which shows that the live bird trading is highly relevant with the distribution of cases.We identified 13 hot spots in the cities including Hangzhou,Shenzhen,et al,where clustered cases have emerged.Conclusion The numbers of human cases are significantly high in cities where FMLB are detected positive for H7N9 virus.These virus positive markets usually affect the people's residence within 5km area.The number and location of FMLB in cities should be re-evaluated and re-planed for healthy city where the risk of residents infecting avian influenza virus is greatly reduced or eliminated.
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Objective This paper summarizes the safety management of 13 ARDS patients resulting from influenza A (H7N9) virus infection with daily awakening during analgesia and sedation treatment.Methods Safety management was given to 13 ARDS patients with influenza A (H7N9) virus infection during analgesia and sedation treatment.Results No serious complications or adverse events occurred during interruption period of analgesia and sedation.Conclusions To give safety management of daily awakening to patients with influenza A (H7N9) virus infection during analgesia and sedation treatment can increase treatment effect and facilitate early recovery of patients.