Live poultry markets（LPMs） are crucial places for human infection of influenza A（H7N9 virus）.In Yangtze River Delta,LPMs were closed after the outbreak of human infection with avian influenza A（H7N9） virus,and t...Live poultry markets（LPMs） are crucial places for human infection of influenza A（H7N9 virus）.In Yangtze River Delta,LPMs were closed after the outbreak of human infection with avian influenza A（H7N9） virus,and then reopened when no case was found.Our purpose was to quantify the effect of LPMs＇ operations in this region on the transmission of influenza A（H7N9） virus.We obtained information about dates of symptom onset and locations for all human influenza A（H7N9） cases reported from Shanghai,Jiangsu and Zhejiang provinces by May 31,2014,and acquired dates of closures and reopening of LPMs from official media.A two-phase Bayesian model was fitted by Markov Chain Monte Carlo methods to process the spatial and temporal influence of human cases.A total of 235 cases of influenza A（H7N9） were confirmed in Shanghai,Jiangsu and Zhejiang by May 31,2014.Using these data,our analysis showed that,after LPM closures,the influenza A（H7N9） outbreak disappeared within two weeks in Shanghai,one week in Jiangsu,and one week in Zhejiang,respectively.Local authorities reopened LPMs when there was no outbreak of influenza A（H7N9）,which did not lead to reemergence of human influenza A（H7N9）.LPM closures were effective in controlling the H7N9 outbreak.Reopening of LPM in summer did not increase the risk of human infection with H7N9.Our findings showed that LPMs should be closed immediately in areas where the H7N9 virus is confirmed in LPM.When there is no outbreak of H7N9 virus,LPMs can be reopened to satisfy the Chinese traditional culture of buying live poultry.In the long term,local authorities should take a cautious attitude in permanent LPM closure.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
Avian influenza has become a serious public health problem. Risk factors for human cases are direct or closed contact with ill, died poultry and live poultry markets （LPMs） exposure.
H9N2 subtype avian influenza virus(AIV)is an influenza A virus that is widely spread throughout Asia,where it jeopardizes the poultry industry and provides genetic material for emerging human pathogens.To better under...H9N2 subtype avian influenza virus(AIV)is an influenza A virus that is widely spread throughout Asia,where it jeopardizes the poultry industry and provides genetic material for emerging human pathogens.To better understand the epidemicity and genetics of H9 subtype AIVs,we conducted active surveillance in live poultry markets(LPMs)in Hubei Province from 2013 to 2017.A total of 4798 samples were collected from apparent healthy poultry and environment.Realtime RT-PCR revealed that the positivity rate of influenza A was 26.6%(1275/4798),of which the H9 subtype accounted for 50.3%(641/1275)of the positive samples.Of the 132 H9N2 viral strains isolated,48 representative strains were subjected to evolutionary analysis and genotyping.Phylogenetic analysis revealed that all H9N2 viral genes had 91.1%–100%nucleotide homology,clustered with genotype 57,and had high homology with human H9N2 viruses isolated from2013 to 2017 in China.Using a nucleotide divergence cutoff of 95%,we identified ten distinct H9N2 genotypes that continued to change over time.Molecular analysis demonstrated that six H9N2 isolates had additional potential glycosylation sites at position 218 in the hemagglutinin protein,and all isolates had I155 T and Q226 L mutations.Moreover,44 strains had A558 V mutations in the PB2 protein and four had E627 V mutations,along with H9N2 human infection strains A/Beijing/1/2016 and A/Beijing/1/2017.These results emphasize that the H9N2 influenza virus in Hubei continues to mutate and undergo mammalian adaptation changes,indicating the necessity of strengthening the surveillance of the AIV H9N2 subtype in LPMs.展开更多
Dear Editor,Avian influenza viruses (AIVs) have posed a serious threat to poultry production and public health. To date, more than fourteen AIV subtypes that are able to infect human beings have been documented. Also,...Dear Editor,Avian influenza viruses (AIVs) have posed a serious threat to poultry production and public health. To date, more than fourteen AIV subtypes that are able to infect human beings have been documented. Also, it is suggested that new subtypes may be reported in the future, owing to the migration of wild birds and live poultry transportation (Gao, 2018).Poultry may act as a potential incubator for novel subtypes of avian influenza virus (Bi et al., 2016a; Bi et al., 2016b; Liu et al., 2014a; Su et al., 2017). Up to date, the H7N9 AIV emerged in February 2013 has caused 1,567 human cases,with a fatality rate of 39.2%(http://www.who.int/influenza/展开更多
文摘Live poultry markets（LPMs） are crucial places for human infection of influenza A（H7N9 virus）.In Yangtze River Delta,LPMs were closed after the outbreak of human infection with avian influenza A（H7N9） virus,and then reopened when no case was found.Our purpose was to quantify the effect of LPMs＇ operations in this region on the transmission of influenza A（H7N9） virus.We obtained information about dates of symptom onset and locations for all human influenza A（H7N9） cases reported from Shanghai,Jiangsu and Zhejiang provinces by May 31,2014,and acquired dates of closures and reopening of LPMs from official media.A two-phase Bayesian model was fitted by Markov Chain Monte Carlo methods to process the spatial and temporal influence of human cases.A total of 235 cases of influenza A（H7N9） were confirmed in Shanghai,Jiangsu and Zhejiang by May 31,2014.Using these data,our analysis showed that,after LPM closures,the influenza A（H7N9） outbreak disappeared within two weeks in Shanghai,one week in Jiangsu,and one week in Zhejiang,respectively.Local authorities reopened LPMs when there was no outbreak of influenza A（H7N9）,which did not lead to reemergence of human influenza A（H7N9）.LPM closures were effective in controlling the H7N9 outbreak.Reopening of LPM in summer did not increase the risk of human infection with H7N9.Our findings showed that LPMs should be closed immediately in areas where the H7N9 virus is confirmed in LPM.When there is no outbreak of H7N9 virus,LPMs can be reopened to satisfy the Chinese traditional culture of buying live poultry.In the long term,local authorities should take a cautious attitude in permanent LPM closure.
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.
文摘Avian influenza has become a serious public health problem. Risk factors for human cases are direct or closed contact with ill, died poultry and live poultry markets （LPMs） exposure.
基金supported by the National Key Research and Development Program of China(Grant No.2016YFD0500800 to ZL)。
文摘H9N2 subtype avian influenza virus(AIV)is an influenza A virus that is widely spread throughout Asia,where it jeopardizes the poultry industry and provides genetic material for emerging human pathogens.To better understand the epidemicity and genetics of H9 subtype AIVs,we conducted active surveillance in live poultry markets(LPMs)in Hubei Province from 2013 to 2017.A total of 4798 samples were collected from apparent healthy poultry and environment.Realtime RT-PCR revealed that the positivity rate of influenza A was 26.6%(1275/4798),of which the H9 subtype accounted for 50.3%(641/1275)of the positive samples.Of the 132 H9N2 viral strains isolated,48 representative strains were subjected to evolutionary analysis and genotyping.Phylogenetic analysis revealed that all H9N2 viral genes had 91.1%–100%nucleotide homology,clustered with genotype 57,and had high homology with human H9N2 viruses isolated from2013 to 2017 in China.Using a nucleotide divergence cutoff of 95%,we identified ten distinct H9N2 genotypes that continued to change over time.Molecular analysis demonstrated that six H9N2 isolates had additional potential glycosylation sites at position 218 in the hemagglutinin protein,and all isolates had I155 T and Q226 L mutations.Moreover,44 strains had A558 V mutations in the PB2 protein and four had E627 V mutations,along with H9N2 human infection strains A/Beijing/1/2016 and A/Beijing/1/2017.These results emphasize that the H9N2 influenza virus in Hubei continues to mutate and undergo mammalian adaptation changes,indicating the necessity of strengthening the surveillance of the AIV H9N2 subtype in LPMs.
基金supported by the National Natural Science Foundation of China (81401312, 81373141, 81502857)National Grand Project on Prevention and Control of Major Infectious Diseases (2016ZX10004222-003)+3 种基金the intramural special grant for influenza virus research from the Chinese Academy of Sciences (KJZD-EW-L15)George F. Gao is a leading principal investigator of the National Natural Science Foundation of China Innovative Research Group (81621091)Weifeng Shi is supported by the Taishan Scholars program of Shandong Province (ts201511056)Yuhai Bi is supported by the Youth Innovation Promotion Association of Chinese Academy of Sciences (CAS) (2017122)
文摘Dear Editor,Avian influenza viruses (AIVs) have posed a serious threat to poultry production and public health. To date, more than fourteen AIV subtypes that are able to infect human beings have been documented. Also, it is suggested that new subtypes may be reported in the future, owing to the migration of wild birds and live poultry transportation (Gao, 2018).Poultry may act as a potential incubator for novel subtypes of avian influenza virus (Bi et al., 2016a; Bi et al., 2016b; Liu et al., 2014a; Su et al., 2017). Up to date, the H7N9 AIV emerged in February 2013 has caused 1,567 human cases,with a fatality rate of 39.2%(http://www.who.int/influenza/
