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Objective:To analyze the genetic evolution and molecular characteristics of H5N8 avian influenza viruses (AIVs) isolated from the poultry in a live poultry market (LPM) in Urumqi, Xinjiang.Methods:Oropharyngeal and cloacal swabs of poultry were collected from a LPM in Urumqi in 2016. AIVs were isolated by inoculating swab samples into chicken embryos. Hemagglutination test and RT-PCR were used to identify the AIVs. The genes of isolated AIVs were amplified with the universal primers of AIV and whole-genome sequencing was also performed. Pairwise sequence alignment and analysis of phylogenetic and molecular characteristics were performed using BLAST, Clustal W, MEGA-X and DNAStar software.Results:Five H5N8 AIVs were isolated from poultry. These strains shared a nucleotide identity of 99.70%-100.00%, which indicated that they were from the same source, and were named XJ-H5N8/2016. Phylogenetic analysis based on hemagglutinin( HA), NS and PB2 genes showed that these isolates were clustered together with H5N8 AIVs isolated from the migratory swans in Hubei, Shanxi and Sanmenxia, and the ducks in India during 2016 to 2017. Moreover, they were also clustered together with H5N6 AIVs isolated from minks in China and the first case of human infection in Fujian. The phylogenetic tree of neuraminidase( NA) gene indicated the five isolates clustered together with H5N8 AIVs isolated from ducks in India in 2016, and the phylogenetic trees of PB1, MP, PA and NP genes showed that they were clustered together with H5N8 AIVs isolated from wild birds and poultry in Egypt, Cameroon, Uganda, Congo and other African countries in 2017. The HA cleavage sites of XJ-H5N8/2016 contained five consecutive basic amino acids, indicating high pathogenicity. Multiple mutations in the genes of XJ-H5N8/2016 could enhance its virulence and pathogenicity to mammals. Conclusions:The five strains of H5N8 AIVs isolated from the LPM were highly pathogenic and closely related to the H5N8 AIVs isolated from migratory birds and poultry in Hubei, Shanxi, Sanmenxia area, Africa and India during 2016 to 2017. Meanwhile, some of the viral genes were also closely related to the H5N6 AIVs isolated from the minks and human in China. Multiple mutations could increase the virulence and pathogenicity of AIVs to mammals, which could pose a potential threat to public health.
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Objective To explore the source of human infection H9N2 avian influenza virus (AIV). Methods Environmental AIV nucleic acid monitoring was conducted for live poultry markets in Changsha city from 2014 to 2015, and data of human infection H9N2 subtype AIV cases worldwide were collected. Phylogenetic trees of hemagglutinin(HA), neuraminidase(NA)and non-structural protein(NS)genes from human infection H9N2 subtype AIV, the live poultry markets environmental H9N2 subtype AIV and partial avian H9N2 subtype AIV were constructed using the MEGA 6.06 software, respectively. Results In 2014-2015, H9 subtype AIV had the highest nucleic acid positive rate (44.76%) in the live poultry markets environment of Changsha city, and the pollution was serious. A total of 27 cases of human infection with H9N2 subtype AIV had been reported worldwide, and most of these patients recovered after treatments.Epidemiological survey showed that 59.26% (16/27) of cases had a clear history of exposure to poultry or live poultry markets. The phylogenetic trees of HA, NA and NS genes showed that the human infection H9N2 subtype AIV isolates isolated from Hunan and Guangdong were closely related to the H9N2 subtype AIV isolated from the live poultry markets environment in Hunan and Guangdong provinces from 2013 to 2016. The nucleotide similarity was as high as 97%-99%. Conclusion Live poultry market is one of the sources of human infection with H9N2 influenza virus.
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Objective@#To analyze the distribution and the molecular biological characteristics of variant subtypes (H5, H7 and H9) of avian influenza virus (AIV) in the live poultry related external environment of Quanzhou form 2014 to 2017, and provide regional references for the prevention, control and early-warning of human infections.@*Methods@#Samples from monitoring sites of live poultry were collected in Quanzhou from 2014 to 2017. Influenza A and variant subtypes of AIV (H5, H7 and H9) were detected by real time RT-PCR, and the detection results were further analyzed statistically. Furthermore, the HA and NA genes of four representative H7N9 strains were sequenced, and the results were further analyzed with DNAstar and MEGA7.0.@*Results@#Among the samples from external environment, the positive rate of nucleic acid of influenza A was 29.04% (377/1 289), of which the positive rates of H5, H7 and H9 subtypes were 3.80%, 13.34% and 12.02%, respectively. The positive rate of H7N9 was higher than those of the other subtypes in all monitored years, of which the highest rate was found in 2017 (21.88%). As to the different types of samples, chopping board possessed the highest positive rate of influenza A (65.4%), followed by waste water (59.3%) and drinking water for the poultry (29.6%). Among the different monitoring sites, the positive rate of poultry farm is 6.94%, far lower than that in the open air (61.7%) and the live poultry trading market (52.8%). Sequencing of the HA and NA genes of four strains of H7N9 showed that the strains from external environment and the strains from H7N9 patients belonged to Pearl River Delta and Yangtze River Delta lineage, respectively. The cleavage sites of HA proteins of these four strains were all PKGR/G without highly pathogenic mutation. Meanwhile, they were low pathogenic H7N9 without oseltamivir resistant mutation (R292 K in NA), while they all possessed the E627 K mutation in the PB2 genes associated with virulence.@*Conclusions@#H7N9 AIV existed in the live poultry related external environment of Quanzhou, especially the farmers’ and the live poultry trading market, so that more persistent surveillance could be needed in the future.
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Short-term closing live poultry markets have been frequently adopted to control H7N9 epidemic.To evaluate the effect of short-term closing live poultry markets,we analyzed the data of environment surveillance of H7 by RT-PCR,and the human H7N9 cases in Zhongshan City from Feb 2014 to May 2017.RRx =The positive rate during the x-th week after closing / the positive rate of the week before closing days * 100％.Three rounds of short-term closing live poultry markets were administered.Round one:from Feb 10 to 23,2014,the neighboring cities didn't synchronize.The H7 positive rate increased since the trade recovered,and RR1 =0.40 (95％CI:0.28-0.59),RR3 =0.63 (95％CI:0.32-1.24),RR4 =0.83 (95％CI:0.48 -1.46).Two human cases were reported in May,2014.Round two:from Feb 19 to 28,2015,the neighboring cities synchronized as the province policy.The H7 positive rate maintained a level lower than 10％ since the trade recovered,and RR1 =0.15 (95％CI:0.07-0.34),RR2=0.21 (95％CI:0.10-0.41),RR3 =0.03 (95％CI:0.00-0.18),RR4 =0.10 (95％CI:0.04-0.27).No more human cases reported in that epidemic season.Round three:from Jan 8 to 21,2017,the neighboring cities didn't synchronize with Zhongshan City.The H7 positive rate had increased since the trade recovered,and RR1 =0.25 (95 ％ CI:0.09-0.68),RR3 =0.37 (95％CI:0.14-1.00),RR4 =1.07 (95％CI:0.54-2.11).Two human cases were reported in Feb,2017.Results indicated that,if the policy of closing live poultry markets was administered in single city,the environment pollution rate would rise shortly and the risk of human infection would increase once the trade recovered.However,if it was synchronously administered in all the cities in one region,the environment pollution rate could maintain at a low level and the risk of human infection would reduce enormously.
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Objective To investigate the distribution of avian influenza A viruses in external environment in Urumqi City in order to provide reference for the prevention and control of human infection with avian influenza virus in Urumqi City.Methods Environmental specimens were collected from 2013 to 2015 to detect avian influenza A virus nucleic acid with real-time fluorescent PCR.The positive specimens were further analyzed to identify the subtypes of avian influenza A viruses.Results A total of 1 043 environmental specimens were collected and tested.Among them,123 specimens were positive for avian influenza A virus nucleic acid with an overall positive rate of 11.79%.H9 was the predominant subtype,accounting for 7.77% of all specimens.Quarterly detection rates of avian influenza A virus in the three years peaked in different quarters of the year.Of all surveillance sites,live poultry markets in urban and rural areas had the highest positive rate (14.23%).Specimens collected from poultry drinking water (18.44%) and other specimens (19.44%) were highly positive for avian influenza A virus.Conclusion Avian influenza A viruses,especially the subtypes of H5,H7 and H9,exist in live poultry markets in Urumqi City.It is necessary to conduct surveillance and health education among people exposed to poultry in live poultry markets.
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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 human exposure to live poultry (poultry feeding and purchasing) in the residents in Beijing and related factors during the second wave of avian influenza A (H7N9) epidemic during 2013-2014, and provide scientific evidence for avian influenza prevention and control. Methods A total of 7366 adults aged ≥18 years were selected through multi-stage stratified sampling in Beijing for a questionnaire survey. Logistic regression model was used to analyze the influence factors of human exposure to live poultry. Results The live poultry feeding rate and live poultry purchasing rate in residents in Beijing in the past year were 5.3%(95%CI:4.8%-5.8%) and 6.0% (95%CI: 5.5%-6.5%) respectively. Logistic regression analysis indicated that lower educational level of primary school and below, (OR=1.82, 95%CI:1.22-2.72);being farmer (OR=2.49, 95%CI:1.89-3.29) or being unemployed (OR=1.65, 95%CI:1.08-2.52);being non local resident (OR=1.54, 95%CI:1.10-2.16);living in suburban area (OR=2.36, 95%CI:1.77-3.16);having one child (OR=1.76, 95%CI: 1.42-2.17) or ≥2 children (OR=2.15, 95%CI: 1.43-3.22) in the family were the risk factors associated with feeding poultry compared with higher educational level of college and above, being employed, being local resident, living in urban area and having no child. And being farmer (OR=1.61, 95%CI:1.27-2.02);being non local resident (OR=1.76, 95%CI:1.31-2.35);living in suburban area (OR=2.05, 95%CI:1.61-2.61);having one child (OR=1.24, 95%CI:1.02-1.52) or ≥2 children (OR=1.78, 95%CI: 1.21-2.63) were the risk factors for purchasing live poultry. Conclusion Some residents living in Beijing still have exposure to live poultry, and targeted measures should be taken to reduce the exposure to poultry.
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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 human exposure to live poultry (poultry feeding and purchasing) in the residents in Beijing and related factors during the second wave of avian influenza A (H7N9) epidemic during 2013-2014, and provide scientific evidence for avian influenza prevention and control. Methods A total of 7366 adults aged ≥18 years were selected through multi-stage stratified sampling in Beijing for a questionnaire survey. Logistic regression model was used to analyze the influence factors of human exposure to live poultry. Results The live poultry feeding rate and live poultry purchasing rate in residents in Beijing in the past year were 5.3%(95%CI:4.8%-5.8%) and 6.0% (95%CI: 5.5%-6.5%) respectively. Logistic regression analysis indicated that lower educational level of primary school and below, (OR=1.82, 95%CI:1.22-2.72);being farmer (OR=2.49, 95%CI:1.89-3.29) or being unemployed (OR=1.65, 95%CI:1.08-2.52);being non local resident (OR=1.54, 95%CI:1.10-2.16);living in suburban area (OR=2.36, 95%CI:1.77-3.16);having one child (OR=1.76, 95%CI: 1.42-2.17) or ≥2 children (OR=2.15, 95%CI: 1.43-3.22) in the family were the risk factors associated with feeding poultry compared with higher educational level of college and above, being employed, being local resident, living in urban area and having no child. And being farmer (OR=1.61, 95%CI:1.27-2.02);being non local resident (OR=1.76, 95%CI:1.31-2.35);living in suburban area (OR=2.05, 95%CI:1.61-2.61);having one child (OR=1.24, 95%CI:1.02-1.52) or ≥2 children (OR=1.78, 95%CI: 1.21-2.63) were the risk factors for purchasing live poultry. Conclusion Some residents living in Beijing still have exposure to live poultry, and targeted measures should be taken to reduce the exposure to poultry.
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Due to adverse economic impact and social panic influences,live poultry market closure(LPM) as an effective control strategy of H7N9 influenza has become the focus of public repeatedly.So this paper reviewed transmission characteris tics of H7N9 influenza,impact of LMP on human H7N9 infection,and the effect of LMP on H7N9 influenza control.
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The distribution and prevalence of low pathogenic avian influenza virus in major live poultry wholesale markets around the Dongting Lake region ,China were investigated in our study to propose prevention and control measures on low pathogenic avian flu in the area of live poultry wholesale market .The samples were injected to SPF chicken embryos by allanto-ic cavity ,and then the allantoic fluid were harvested and used for hemagglutination (HA) .If it was positive by HA ,subtypes of the virus would be determined by hemagglutination inhibition (HI) and RT-PCT .We isolated 627 low pathogenic avian in-fluenza viruses in major live poultry wholesale market around Dongting Lake region systematically in winter and spring during 2009-2011 ,and the total separation rate was 22 .2% .The duck swab separation rate of low pathogenic avian influenza was the highest ,which was 24 .6% ,and the following was chicken swab that reached 21 .5% ,and the goose swab separation rate was 11% .We isolated 6 HA subtypes including H3 ,H4 ,H6 ,H9 ,H10 ,and H11 in every live poultry wholesale market ,and the separation rate of H9 ,H6 and H4 subtypes was relatively high ,which could reach 11% ,6 .3% and 3 .4% ,respectively . Those results indicated that recessive infection of low pathogenic avian influenza virus was serious in live poultry wholesale mar-ket around the Dongting Lake area ,and it was a great threat to the occurrence of avian flu .
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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.