| Studies have found that H5N2HPAIV may distribute in poultry and bring economic loss. In the natural state, H5N2HPAIV or LPAIV could infect both wild birds and mammals, including human. H5N2LPAIV exists extensively in wild birds and wild birds play an important role in the transmission of this virus. The detection of H5N2subtype AIV in wild birds may reflect virus-carrying status in them and provide important information for the viral genetic variation.Three hundred swab samples were collected in Xianghai National Nature Reserve in Jilin province, China in October2011and five H5N2viruses were selected based on their host species after preliminary detection and identification. The deduced amino acid sequences at the cleavage site of the HA protein demonstrated that all five isolates had low pathogenicity. Certain virulence-associated loci in the deduced amino acid sequences were also analyzed and high-virulence-associated amino acids were found, which had pathogenic potential in rats and swine. Phylogenetic tree and nucleotide homology analysis revealed that all the gene segments were clustered in the Eurasian lineage, and nucleotide homology between the five isolates was greater for HA and NA than the six internal genes (PB2, PB1, PA, M, NP and NS). Internal gene reassortment occurred frequently between the same genes of different isolates or between different genes of the same isolate, even though their external genes were highly homologous. The proximity of the host genetic relationship was able to affect internal gene reassortment. The genomes of the five isolates formed three different genome constellations, and it may be that the taxonomic differences led to a significant difference in the constitution of genome constellations between isolate429(from grebe) and the other four isolates (from different wild ducks). |
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