Whole genomic analysis of 8 strains of H9N2 subtype avian influenza virus isolates from live poultry markets in Yunnan, 2023
- Author:
LIU Zhaosheng
;
FU Xiaoqing
;
LUO Chunrui
- Publication Type:Journal Article
- Keywords:
Avian influenza;
genome;
high/low pathogenicity;
Yunnan Province
- From:
China Tropical Medicine
2025;25(3):350-
- CountryChina
- Language:Chinese
-
Abstract:
Objective To conduct an in-depth study of the molecular biological characteristics and evolutionary trends of H9N2 avian influenza virus (AIV) in live poultry markets in Yunnan Province in 2023, and to provide scientific evidence for the development of control strategies for H9N2 avian influenza in the region. Methods Environmental samples were collected from live poultry markets in Yunnan Province in 2023 for H9N2 subtype nucleic acid detection. Positive samples were subjected to virus isolation using chicken embryos, and the genome of the 8 isolated strains was amplified, sequenced, and analyzed for genetic characteristics. Results The eight avian influenza virus (AIV) isolates had the hemagglutinin (HA) cleavage site sequence PSRSSRGLF, which is a non-continuous basic amino acid sequence, consistent with the genetic characteristics of typical low-pathogenicity avian influenza viruses. Mutations Q234L and H191N were observed in the left arm of the HA protein, which enhanced the affinity for α-2,6 sialic acid receptors, suggesting that these viruses may have the potential to infect humans. The neuraminidase (NA) protein exhibited a deletion of three amino acids (TEI) at positions 62–64 in the stalk region, displaying characteristics of high pathogenicity at the molecular level. The increase or absence in potential glycosylation sites were observed in both HA and NA genes. The non-structural protein 1 (NS1) showed no D92E mutation, and had a C-terminal truncation of 13 amino acids, indicating that this virus is of low pathogenicity and poses a lower risk of human transmission. Mutations T37A, R95K, S224N, and K242N in the M1 protein of some isolates increased the risk of infection, while one isolate carried the V27A or S31N mutation in the M2 protein, conferring resistance to M2 ion channel inhibitors. Mutations M317I and S678N were identified in the PB1 protein, which may enhance pathogenicity in mice and increase the potential for mammalian infection. The PB2 protein carried the I292V mutation, which exhibited a stronger infectivity to mammals. Phylogenetic analysis revealed that the HA, NA, and PB2 gene segments belonged to the Y280 lineage, NP and PB1 gene segments were classified under the F98 lineage, the M gene segment of the NH013 isolate belonged to the F98 lineage, while M genes, as well as the NS and PA genes of other isolates belonged to the G1 lineage. Conclusions These eight AIV isolates exhibited characteristics of low pathogenicity, but simultaneously carry the potential risk of infecting humans. Despite the HA cleavage site and NS1 protein mutations indicating low pathogenicity, the Q234L and H191N mutations in the HA protein enhanced its affinity for human receptors, suggesting the potential for human infection. The TEI deletion in the NA protein, mutations in the M1 protein, and resistance mutations in the M2 protein further increase the risk of human infection. Mutations in the PB1 and PB2 proteins increase the potential for these eight AIV strains to infect humans or mammals.
- Full text:202511191648448233716.Whole genomic analysis of 8 strains of H9N2 subtype avian influenza virus isolates from live poultry markets in Yunnan, 2023.pdf
