Abstract
The genotypes of the H9N2 avian influenza viruses have changed since 2013 when almost all H9N2 viruses circulating in chickens in China were genotype 57 (G57) with the fittest lineage of each gene. To characterize the H9N2 variant viruses from 2011 to 2014, 28 H9N2 influenza viruses were isolated from live poultry markets in China from 2011-2014 and were analyzed by genetic and biological characterization. Our findings showed that 16 residues that changed antigenicity, two potential N-linked glycosylation sites, and one amino acid in the receptor binding site of the HA protein changed significantly from 2011-2014. Moreover, the HA and NA genes in the phylogenetic tree were mainly clustered into two independent branches, A and B, based on the year of isolation. H9N2 virus internal genes were related to those from the human-infected avian influenza viruses H5N1, H7N9, and H10N8. In particular, the NS gene in the phylogenetic tree revealed genetic divergence of the virus gene into three branches labeled A, B, and C, which were related to the H9N2, H10N8, and H7N9 viruses, respectively. Additionally, the isolates also showed varying levels of infection and airborne transmission. These results indicated that the H9N2 virus had undergone an adaptive evolution and variation from 2011-2014.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Animals
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Antigens, Viral / chemistry
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Antigens, Viral / genetics
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Antigens, Viral / immunology
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Chickens
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China / epidemiology
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Evolution, Molecular
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Gene Expression
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Glycosylation
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Hemagglutinin Glycoproteins, Influenza Virus / chemistry
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Hemagglutinin Glycoproteins, Influenza Virus / genetics
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Hemagglutinin Glycoproteins, Influenza Virus / immunology
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Humans
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Influenza A Virus, H10N8 Subtype / classification
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Influenza A Virus, H10N8 Subtype / genetics
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Influenza A Virus, H10N8 Subtype / immunology
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Influenza A Virus, H5N1 Subtype / classification
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Influenza A Virus, H5N1 Subtype / genetics
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Influenza A Virus, H5N1 Subtype / immunology
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Influenza A Virus, H7N9 Subtype / classification
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Influenza A Virus, H7N9 Subtype / genetics
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Influenza A Virus, H7N9 Subtype / immunology
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Influenza A Virus, H9N2 Subtype / classification
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Influenza A Virus, H9N2 Subtype / genetics*
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Influenza A Virus, H9N2 Subtype / immunology
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Influenza in Birds / epidemiology*
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Influenza in Birds / immunology
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Influenza in Birds / virology
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Influenza, Human / epidemiology*
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Influenza, Human / immunology
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Influenza, Human / virology
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Neuraminidase / chemistry
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Neuraminidase / genetics
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Neuraminidase / immunology
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Phylogeny*
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Polymorphism, Genetic*
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Poultry Diseases / epidemiology*
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Poultry Diseases / immunology
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Poultry Diseases / virology
Substances
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Antigens, Viral
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Hemagglutinin Glycoproteins, Influenza Virus
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hemagglutinin, avian influenza A virus
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Neuraminidase
Grants and funding
This work was supported by the National Natural Science Foundation of China (31672516, 31172300, and 30670079) to HS, Grant No. BE2016343 from Jiangsu province, the Jiangsu University and College Natural Science Foundation (12KJA230002), the Doctoral Program of Higher Education of China (20133250110002), and a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD). Sinopharm Yangzhou VAC Biological Engineering Co., Ltd. provided financial support in the form of a salary for JZ. The specific role of this author is articulated in the "author contributions" section. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.