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@#Abstract: Objective To investigate the molecular characteristics of the H9N2 avian influenza virus (AIV) causing human infection in Yunnan Province in 2019, and to provide the scientific basis for the prevention and control of avian influenza in Yunnan Province. Methods Influenza virus typing was performed by real-time RT-PCR in two influenza-like illness samples, and the Illumina Miseq high-throughput sequencer was used to determine the viral genome sequence. HA and NA gene sequence alignment and phylogenetic tree construction were performed using Mega7.0 software. Results Real-time RT-PCR results showed that two influenza-like illness samples were positive for H9N2 subtype. The full length of HA and NA were obtained by genomic sequencing. Sequence system evolution analysis showed that the HA and NA of the two AIVs in Yunnan Province were in the same evolutionary clade as A/Chicken/Zhejiang/HJ/2007 and belonged to the G57 type. The HA nucleotide and amino acid homology of the two AIVs were 93.92% and 95.00%, respectively, and the NA nucleotide and amino acid homology was 93.31% and 82.03%, respectively. The nucleotide (amino acid) homology of HA was 92.29%-96.94% (93.77%-98.43%) and 92.84%-94.92% (94.18%-96.23%), respectively, and NA nucleotide homology (amino acid) were 91.81%-97.60% (77.82%-94.83%), 94.38%-97.22% (85.47%-94.55%), respectively, compared with that of human infected H9N2 epidemic strains obtained in China from 2015 to 2020. Both AIVs HA protein cleavage site sequences were PSRSSR↓GLF, which was in line with the characteristics of low pathogenic influenza. The analysis of HA protein receptor binding site showed that amino acids at positions 109, 161, 163, 191, 202, 203 and 234 were consistent with the reference strains, while amino acids at position 198 were mutated to T. N166D and 168N mutations were also found in HA protein, and both AIVs had 7 potential glycosylation sites. Analysis of the erythrocyte binding site of NA gene found that there were amino acid mutations at positions 369, 402, 403, and 432, and amino acid deletion at positions 63-65 was found in the NA genes. There were 4 and 5 potential glycosylation sites in the two AIVs, respectively, and no drug resistance site mutations were found. Conclusions The receptor binding sites, erythrocyte binding sites and glycosylation sites of HA and NA genes of H9N2 AIV in Yunnan Province have different degrees of variation, and monitoring and prevention and control should be strengthened.
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Objective: To delineate the H9N2 influenza virus circulation within Iran and its neighboring countries, the potential source of the epidemic in these countries, and its date of origin. Methods: We obtained all hemagglutinin (HA) and neuraminidase (NA) nucleotide sequences of influenza H9N2 available up to December 25, 2020 from Iran and its neighboring countries (i.e., Pakistan, Afghanistan, Turkmenistan, Armenia, Azerbaijan, Turkey, and Iraq). We also performed a Bayesian Markov chain Monte Carlo method to infer the evolutionary dynamic and the most recent common ancestor for the HA and NA sequences. Results: H9N2 epidemic may have started in Iran and Pakistan much earlier than the other investigated countries in the region, and an ongoing bidirectional dispersion of the virus between the investigated countries was also observed. The mean time of the most recent common ancestor of H9N2 viruses was 1988 for HA, and 1992 for NA. Conclusions: Strains from investigated countries rooted in Pakistan and Iran. Regular surveillance of H9N2 viruses, especially in the live bird markets, enhancing the biosecurity of poultry industry and screening newly arriving immigrants and tourists from neighboring countries at border should be considered to control spread of the virus. Furthermore, surveillance of viral molecular evolution should be initiated for effective prevention of epidemic and pandemic spreads.
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@#Objective To analyze genetic characteristics of hemagglutinin( HA) gene of H9N2 avian influenza viruses( AIVs) circulating in Anhui Province from 2013 to 2018． Methods All H9N2 positive samples tested by real－time polymerase chain reaction( PCＲ) were inoculated into specific patho- gen free ( SPF) chicken eggs for isolation and purification． Viral ＲNA was reversely transcribed into cD- NA and then amplified with gene specific primers． PCＲ products were sequenced and the gene sequences were analyzed using molecular and bioinformatics software． The DATAMONKEY online server was conducted to analyze selection pressure，and protein structure homology modelling was computed by the SWISS－MODEL server． Ｒesults 33 H9N2 AIVs isolated from live poultry markets belonged to h9．4．2．5 in the phylogenetic tree． The receptor binding sites of HA gene at 183，226 and 227 position were mutated into N，L and M，respectively． Meanwhile 189 and 190 sites presented with genetic polymorphism． Since 2015，all H9N2 viruses in this study carried 6 potential N－linked glycosylation sites． It was found that po- sition 160 of HA gene was subjected greater positive selection pressure，presented 7 spatial conformations at least． Conclusions The H9N2 viruses isolated from live poultry markets in Anhui Province possess the molecular characteristics of infecting mammals and the ability of antigenic drift，so we need to pay more attention to the genetic characteristics of the viruses．
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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 understand the genetic variations of neuraminidase (NA) genes of avian influenza virus H9N2 in Weining,Guizhou Province,and to provide the scientific evidence for the prevention and control of avian influenza virus.Methods Ribonucleic acids (RNA) were extracted and NA genes were amplified and sequenced from 13 randomly selected H9N2 positive samples from the live poultry market (LPM)environments in north of Weining Yi and Hui and Miao autonomous county (Weining),Guizhou Province during 2015 to 2017.Then the homology,genetic evolution,and sites of stalk deletion areas,potential N-glycosylation,receptor binding regions and drug resistance of H9N2 subtype avian influenza viruses were analyzed by a series of bioinformation software.Results Homology analysis revealed that there were 93.0％-100.0％ and 92.1％-100.0％ similarity among 13 strains H9N2 avian influenza viruses in nucleotide and amino acid of the NA gene,respectively.All strains belonged to DK/HK/Y280/97 sub-lineage,but their genetic sources were complex and diverse.Thirteen strains had a stalk deletion of 3 amino acid residues TEI at positions 63-65 and 3 isolates had mutation QN to QK at positions 39-40.The potential N-glycosylation sites at amino acid residues 86,146,200,and 234 of the NA protein of all strains were highly conserved,while other N-glycosylation sites had quantity and site mutations.There were different mutation types at the three sialic acid binding site areas,especially at 399-404 area.All NA protease activity sites and key sites of the 13 strains had no mutations associated with resistance to the neuraminidase inhibitor drugs.Conclusions All 13 strains H9N2 viruses belongs to DK/HK/Y280/97 sub-lineage in Weining,Guizhou Province during 2015-2017,and their genetic sources are complex and diverse.The mutations on sites of stalk areas,potential N-glycosylation and sialic acid binding site areas are presented at different degrees.Hence,enhancing surveillance and controlling H9N2 avian influenza virus is necessary.
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Worldwide, avian influenza H9N2 viruses of different lineages are the most widespread viruses in poultry. However, to date, cases in Russia have not been documented. In this study, we report the first detection of a G1-like H9N2 virus from poultry sampled at live-bird markets in Russia (Far East region) during the winter of 2018 (isolate A/chicken/Amur_Russia/17/2018). We assume there has been further circulation of the A/chicken/Amur_Russia/17/2018 H9N2 virus in the Russian Far East with possible distribution to other regions or countries in 2018–2019.
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Animals , Asia, Eastern , Genotype , Influenza A Virus, H9N2 Subtype , Influenza in Birds , Poultry , RussiaABSTRACT
To evaluate the optimal administration frequency for interferon-α (IFN-α) and the effect of its combined use with inactive virus on chicken flocks, the prokaryotic expression plasmid pET-22b-ChIFN-α was constructed and transferred into Escherichia coli BL21(DE3) host bacteria to induce the expression of chicken IFN-α and to harvest recombinant proteins inclusion bodies. The expression of recombinant chicken IFN-α was confirmed by SDS-PAGE, and the results demonstrated that the chicken IFN-α (20 kDa) was highly expressed using the prokaryotic expression vector with a concentration of 0.2 mg/mL in the medium. Chicken IFN-α was diluted to 2.5×10⁴ U/fowls and administered to immunized specific-pathogen-free chickens orally in combination with inactivated H9N2 subtype influenza virus. Chicken that received chicken IFN-α were safe after three repeated immunizations (96 h). In addition, chicken IFN-α could induce higher levels of antiviral-related inducible genes in peripheral blood, spleen, and thymus of chicken flocks. The results of a challenge assay revealed that the lowest detoxification rates of chicken IFN-α ranged from three to five days, suggesting a higher capacity to resist H9N2 subtype avian influenza virus. The present study obtained the optimal immune frequency and immunization period for chicken IFN-α to provide theoretical support for the optimal clinical application of IFN-α.
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Animals , Humans , Administration, Oral , Chickens , Influenza A Virus, H9N2 Subtype , Interferon-alpha , Virus ReplicationABSTRACT
To investigate the prevalence and the risk factors of H9N2 avian influenza among backyard birds in Iran between October and November 2015. Methods: In this study, a total of 15 500 blood samples and 2 884 cloacal swab samples of backyard birds were collected in villages of Iran between October and November 2015. Then, serum samples were examined with the hemagluttination inhibition test and cloacal swab samples were pooled together and examined by RT-PCR. The samples that had serological titer ≥ 4 (log2) and villages that had at least one seropositive sample were considered positive. Results: Out of 559 villages, 526 (94.10%) were seropositive for the infection. Among 15 500 serum samples, 7 468 (48.18%) samples were seropositive for the infection. The seroprevalence according to species was 54.02% among chickens, 17.59 % among ducks, 18.73% among turkeys, 84.21% among pigeons and 12.15% among ostriches, partridges and pheasants. Based on molecular test, 3.04% villages were positive. The seroprevalence in hot and humid area was less than that in cold and humid area (P<0.05). Conclusions: H9N2 avian influenza has high seroprevalence among backyard birds of Iran. Therefore, preventive measures such as biosecurity Practices and monitoring should be applied to reduce the prevalence.
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To investigate the prevalence and the risk factors of H9N2 avian influenza among backyard birds in Iran between October and November 2015. Methods: In this study, a total of 15 500 blood samples and 2 884 cloacal swab samples of backyard birds were collected in villages of Iran between October and November 2015. Then, serum samples were examined with the hemagluttination inhibition test and cloacal swab samples were pooled together and examined by RT-PCR. The samples that had serological titer ≥ 4 (log
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The subtype H9N2 avian influenza virus greatly threatens the Chinese poultry industry, even with annual vaccination. Waterfowl can be asymptomatically infected with the H9N2 virus. In this study, three H9N2 virus strains, designated A/Goose/Jiangsu/YZ527/2011 (H9N2, Gs/JS/YZ527/11), A/Goose/Jiangsu/SQ119/2012 (H9N2, Gs/JS/SQ119/12), and A/Goose/Jiangsu/JD564/2012 (H9N2, Gs/JS/JD564/12), were isolated from domestic geese. Molecular characterization of the three isolates showed that the Gs/JS/YZ527/11 virus is a double-reassortant virus, combining genes of A/Quail/Hong Kong/G1/97 (H9N2, G1/97)-like and A/Chicken/Shanghai/F/98 (H9N2, F/98)-like; the Gs/JS/SQ119/12 virus is a triple-reassortant virus combining genes of G1/97-like, F/98-like, and A/Duck/Shantou/163/2004 (H9N2, ST/163/04)-like. The sequences of Gs/JS/JD564/12 share high homology with those of the F/98 virus, except for the neuraminidase gene, whereas the internal genes of Gs/JS/YZ527/11 and Gs/JS/SQ119/12 are closely related to those of the H7N9 viruses. An infectivity analysis of the three isolates showed that Gs/JS/SQ119/12 and Gs/JS/YZ527/11 replicated well, with seroconversion, in geese and chickens, the Gs/JS/JD564/12 did not infect well in geese or chickens, and the F/98 virus only infected chickens, with seroconversion. Emergence of these new reassortant H9N2 avian influenza viruses indicates that these viruses can infect both chicken and goose and can produce different types of lesions in each species.
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Animals , Humans , Asian People , Chickens , Geese , Influenza A Virus, H7N9 Subtype , Influenza A Virus, H9N2 Subtype , Influenza in Birds , Neuraminidase , Population Characteristics , Poultry , Sequence Analysis , Seroconversion , VaccinationABSTRACT
In 2013, two episodes of influenza emerged in China and caused worldwide concern. A new H7N9 avian influenza virus (AIV) first appeared in China on February 19, 2013. By August 31, 2013, the virus had spread to ten provinces and two metropolitan cities. Of 134 patients with H7N9 influenza, 45 died. From then on, epidemics emerged sporadically in China and resulted in several victims. On November 30, 2013, a 73-year-old woman presented with an influenza-like illness. She developed multiple organ failure and died 9 d after the onset of disease. A novel reassortant AIV, H10N8, was isolated from a tracheal aspirate specimen that was obtained from the patient 7 d after onset. This case was the first human case of influenza A subtype H10N8. On 4 February, 2014, another death due to H10N8 avian influenza was reported in Jiangxi Province, China.
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Aged , Female , Humans , China , Epidemiology , Influenza A Virus, H10N8 Subtype , Classification , Influenza A Virus, H7N9 Subtype , Classification , Influenza A Virus, H9N2 Subtype , Classification , Influenza, Human , Epidemiology , Virology , Phylogeny , Reassortant Viruses , ClassificationABSTRACT
The high prevalence of influenza A virus is identified in Hunan Province because of the high density of poultry farms. To survey the variations of H9N2 subtype avian influenza virus in Hunan province, we analyzed HA and NA genes of 10 virus strains isolated from different areas of Hunan Province. All these strains belong to the Eurasian lineage, Y280-like sub-lineage. The cleavage sites in their HA genes were all RSSR↓GLT, corresponding to the feature of low pathogenic AIV. All strains had an L (Leu) at the site 234 in the HA genes, indicating the ability of binding with the SAα-2,6 receptor. NA gene stalk deletions at aa 63-65 were also detected from all the isolates, indicating a possibility of increased virus replication in mammals. Our findings suggest that more attention should be paid to the surveillance of H9N2 influenza virus and its direction of reassortment.
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The HA gene of H9N2 influenza virus (A/chicken/Hunan/04.14 (H9N2)) was amplified and sequenced. The RNA was synthesized by in vitro transcription. The RNA transcription solutions were diluted to 10⁹ copies/μL using the RNA storage solution. The aliquoted RNA solutions were used to evaluate the homogeneity and stability. The results were determined by the average value obtained from four independent laboratories. Furthermore, the fluorescence quantitative RT-PCR method was also developed to verify the detection accuracy of clinical samples. The detection limit of this method is approximately 10 copies. Taken together, the RNA transcription solution established in our study can used as positive standard reference for rapid detection of H9N2 influenza virus.
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We investigated and analyzed the first case of human infection with avian influenza A(H9N2) virus in Yunnan Province,China,so as to provide a better basis for preventing and controlling human infections with viruses of animal origin in the future.We carried out the field epidemiological survey among the patient,close contacts and the live poultry markets,detected and analyzed the samples from patient and the outdoor environment.Results showed that the 9-month-old boy was a case of human infection with avian influenza A(H9N2) virus with the history of live poultry markets exposure and the results of nucleic acid detection and virus isolation.There was a lot of contamination of the avian influenza virus in the live poultry markets.The second generation cases have not occurred.The monitoring of pneumonia of unknown etiology and influenza like cases in medical institutions is the important means to find timely cases of human infected with avian influenza.Regular disinfection and closing-down of live poultry markets are key measures to reduce the exposure opportunity.
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We analyzed the evolutional and molecular characteristics of Hemagglutinin(HA),Neuraminidase(NA) and nonstructural(NS) genes of avian influenza A(H9n2) viruses from environment in poultry markets in Changsha,China,2014,providing laboratory data for prevention and control of human infection with avian influenza A(H9N2) virus.Five hundred and one specimens (263 poultry drinking water specimens,226 poultry sewage specimens and 17 others specimens) were collected from environment in poultry markets in Changsha,2014,and real-time RTPCR was used for influenza A typing and subtyping (H5,H7 and H9) detection.HA and NA universal primer sets for conventional RT-PCR and sequencing were used for the positivity of single H9.The sequence homology of HA,NA and NS genes of the viruses were analyzed with the online Basic Local Alignment Search Tool (BLAST).The ClustalW multiple alignments of amino acids and the phylogenetic trees for HA,NA and NS genes were constructed using the BioEdit and MEGA 5 software,respectively.Results showed that among 501 environmental samples,350 samples were positive for influenza A virus,191 (38.12％) for H9 subtype,177 (35.33％) for H5 subtype,11 (2.20％) for H7 subtype and 68 (13.57％) for H5 and H9 subtypes co-detection.Twenty-three H9N2 subtype AIV were confirmed by conventional RT-PCR and sequencing from the samples of the positivity of single H9.Phylogenetic analysis revealed that most of HA,NA and NS genes of the H9N2 subtype AIV isolated in Changsha City had gene constellations of genotype S,and these virues might have acquired their HA,NA and NS from A/Chicken/Shanghai/F/1998-like (H9N2).L235 (correspond to H3 numbering 226) of the HA protein of the receptor binding site (RBS) were found in these H9N2 viruses,and the characteristics was shown to be associated with increased affinity of HA to the glycan-receptors of human influenza virus,and the low pathogenicity molecular characteristics of HA,NA and NS genes were showed in these viruses.The positive rate of nucleic acid of the H9 subtype of avian influenza virus from environment was the highest in poultry markets in Changsha,2014,and molecular characteristics of the HA,NA and NS of these H9N2 subtype AIV showed low pathogenicity,but that may facilitate human infection.So,the prevalence and genetic evolution of this virus should be closely monitored.
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We summarized the epidemiological investigation results of the first case of human infection with avian influenza A(H9N2) virus in Chengdu,China,in order to provide references for dealing with similar diseases scientifically in the future.The methods of field epidemiology and laboratory testing were used to collect the H9N2 case's clinical and epidemiological data,as well as collect and test the samples of the H9N2 case and the relevant environment,so that the possible sources of infection,the epidemiological characteristics and clinical features could be analyzed.Results showed that the H9N2 case contacted with poultry within 10 days before the onset of illness and the H9N2 virus nucleic acid was detected in the patient's specimen by PCR.This case suffered from several chronic diseases for a long time,although active treatments were taken this time,she died soon after onset.Her living environment,the chicken leftovers from cooking,and surrounding poultry markets were polluted by H9 avian influenza virus.Through the investigation,we could deduce that the infection source of this case was the chicken infecting H9N2 viruses from surrounding poultry markets.This would be the first fatality associated with influenza A (H9N2) virus infections in humans.And though avian influenza A(H9N2) virus was low pathogenic,infection could cause severe symptoms or death in people with severe underlying diseases.
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[ ABSTRACT] AIM:To investigate whether kaempferol protects against acute lung injury induced by swine -origin influenza A H9N2 virus via down-regulation of NF-κB signaling pathway .METHODS:BALB/c mice were used to estab-lish the animal model of acute lung injury by nasal inoculation of swine-origin influenza A H9N2 virus.After the interven-tion with kaempferol , the pulmonary edema was evaluated by determining the lung wet weight /dry weight ( W/D) ratio, the pathological changes of the lung tissues were observed , the concentrations of TNF-α, IL-1βand IL-6 in the bronchoalveolar lavage fluid (BALF) were measured, and superoxide dismutase (SOD) activity, myeloperoxidase (MPO) activity and MDA content in the homogenate of the lung tissues were detected .NF-κB P65 levels were determined by Western blot , and the NF-κB P65 and NF-κB P50 nuclear translocation in the nuclear extracts from mouse lung tissue homogenate was detec-ted by ELISA .RESULTS:Treatment with kaempferol decreased the morality of infected mice , and significantly prolonged the survival time of the infected mice .Kaempferol also relieved the pathological changes of the lung tissues , the lung W/D ratio and the lung index in swine-origin influenza A H9N2 virus-infected mice.Treatment with kaempferol significantly de-creased the infiltration of inflammatory cells including macrophages , lymphocytes and neutrophils in the BALF .The levels of TNF-α, IL-6, IL-1βand MDA and the activity of MPO were also decreased .Treatment with kaempferol also significantly increased the SOD activity .NF-κB P65 levels were decreased , and the NF-κB P65 and NF-κB P50 nuclear translocation in the nuclear extracts from the mouse lung tissue homogenate were also decreased by treatment with kaempferol .CONCLU-SION:The protective effect of kaempferol on the mice with acute lung injury induced by swine -origin influenza A H9N2 vi-rus is related to suppression of the oxidative stress and inflammatory responses by down-regulation of NF-κB signaling path-way.
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Objective@#To analyze the genome characteristics of an avian influenza A (H9N2) virus isolated from an 11-month-old infant, and to look for possible sources of infection.@*Methods@#Throat swabs were collected from an infant with influenza-like illness in influenza sentinel surveillance hospitals and isolated for influenza viruses using cells. The isolates were identified for influenza virus types and subtypes by the method of hemagglutination assay, hemagglutination inhibition assay and fluorescence PCR. Whole genome sequencing of the isolated virus was carried out. The genome nucleic acid sequences and the deduced amino acid sequences were analyzed by comparing the phylogenetic trees which were constructed by bioinformatics software.@*Results@#A seasonal un-typed influenza virus was isolated from the infant with influenza like illness. With fluorescent PCR method , it was identified as H9N2 subtype of avian influenza virus and the case was confirmed as a human infected with an avian influenza A(H9N2) virus. Epidemiological studies revealed that the case had no clear history of poultry contact and exposure. Blast analysis shows that eight segments of the viral genome are avian origin, and 97.5%-99.8% homology with that of viruses isolated from the live-poultry markets. The virus belongs to G57 genotype, deduced amino acid sequence analysis shows that the virus has typical low pathogenic avian influenza characteristics.@*Conclusions@#Although the case does not have a clear history of contact or exposure to poultry, molecular traceability suggests that possible sources of infection may be still from poultry.
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Objective To understand genomic characteristics of 2 strains of influenza A (H9N2) virus isolated from human infection cases in Anhui province in 2015.Methods Two human infection with H9N2 virus were confirmed by national influenza surveillance laboratory network in Anhui through viral isolation in April and September,2015,respectively.The full genomic sequences of the two viral isolates were analyzed in this study by using molecular bioinformatics software Mega 6.0.Results Human infection with H9N2 virus was first reported in Anhui province.The analysis of genomic sequence showed that the HA and NA genes of the two H9N2 isolates belonged to A/Chicken/ Shanghai/F/98(H9N2)-like lineage,and shared high identity with H9N2 virus circulating in poultry in 2013.The PB2 and MP genes belonged to the A/quail/Hong Kong/G 1/97-like lineage,and shared high homology with H7N9,H10N8 or H6N2 viruses.The amino acid sequence alignment results showed that several mutations for human infection tropism presented in the two virus strains,including Q226L,H183N and E190T in HA;S31N in M2;63-65 deletion in NA.In addition,the H9N2 influenza virus strains possessed the PSRSSR\GL motif in HA.Meanwhile several human-like signatures,including PA-100A,PA-356R and PA-409N were also found in the two virus strains.Conclusion The H9N2 viruses isolated from human infection cases in Anhui province belonged to a reassortant virus originated from different lineage H9N2 avian influenza virus.The virus has possessed several human susceptibility locus.
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Objective To understand genomic characteristics of 2 strains of influenza A (H9N2) virus isolated from human infection cases in Anhui province in 2015.Methods Two human infection with H9N2 virus were confirmed by national influenza surveillance laboratory network in Anhui through viral isolation in April and September,2015,respectively.The full genomic sequences of the two viral isolates were analyzed in this study by using molecular bioinformatics software Mega 6.0.Results Human infection with H9N2 virus was first reported in Anhui province.The analysis of genomic sequence showed that the HA and NA genes of the two H9N2 isolates belonged to A/Chicken/ Shanghai/F/98(H9N2)-like lineage,and shared high identity with H9N2 virus circulating in poultry in 2013.The PB2 and MP genes belonged to the A/quail/Hong Kong/G 1/97-like lineage,and shared high homology with H7N9,H10N8 or H6N2 viruses.The amino acid sequence alignment results showed that several mutations for human infection tropism presented in the two virus strains,including Q226L,H183N and E190T in HA;S31N in M2;63-65 deletion in NA.In addition,the H9N2 influenza virus strains possessed the PSRSSR\GL motif in HA.Meanwhile several human-like signatures,including PA-100A,PA-356R and PA-409N were also found in the two virus strains.Conclusion The H9N2 viruses isolated from human infection cases in Anhui province belonged to a reassortant virus originated from different lineage H9N2 avian influenza virus.The virus has possessed several human susceptibility locus.