Genetic variation and phylogenetic analysis of hemagglutinin genes of H9 avian influenza viruses isolated in China during 2010–2012

Chen, Ruiai; Lai, Hanzhang; Li, Lin; Liu, Yu-Peng; Pan, Weilan; Zhang, Wenyan; Xu, Jiahua; He, Dongsheng; Tang, Zhaoxin

doi:10.1016/j.vetmic.2013.04.005

Cited by 15 publications

(23 citation statements)

References 32 publications

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“…H9N2 viruses have prevailed in chickens in China in recent years and have constantly undergone reassortment, and novel genotypes have continued to emerge (21,22,23,24). The H9N2 virus from live poultry markets in Hangzhou seemed to evolve from the H9N2 virus circulating in chickens in China recently on the basis of the high sequence similarities of all eight segments.…”

Section: Discussionmentioning

confidence: 99%

Influenza H7N9 and H9N2 Viruses: Coexistence in Poultry Linked to Human H7N9 Infection and Genome Characteristics

Jin

Cui

et al. 2014

J Virol

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Avian influenza virus A of the novel H7N9 reassortant subtype was recently found to cause severe human respiratory infections in China. Live poultry markets were suspected locations of the human H7N9 infection sources, based on the cases' exposure histories and sequence similarities between viral isolates. To explore the role of live poultry markets in the origin of the novel H7N9 virus, we systematically examined poultry and environmental specimens from local markets and farms in Hangzhou, using realtime reverse transcription-PCR (RT-PCR) as well as high-throughput next-generation sequencing (NGS). RT-PCR identified specimens positive for the H7 and N9 genomic segments in all of the 12 poultry markets epidemiologically linked to 10 human H7N9 cases. Chickens, ducks, and environmental specimens from the markets contained heavily mixed subtypes, including H7, N9, H9, and N2 and sometimes H5 and N1. The idea of the coexistence of H7N9 and H9N2 subtypes in chickens was further supported by metagenomic sequencing. In contrast, human H7N9 infection cases (n ‫؍‬ 31) were all negative for H9N2 virus according to real-time RT-PCR. The six internal segments were indistinguishable for the H7N9 and H9N2 viruses. The H9, N2, and internal-segment sequences were very close to the sequence of the H9N2 virus circulating in chickens in China recently. Our results provide direct evidence that H9N2 strains coexisted with the novel human-pathogenic H7N9 influenza virus in epidemiologically linked live poultry markets. Avian influenza A virus of the H9N2 subtype likely made a recent contribution to the evolution of the H7N9 virus and continues to do so. IMPORTANCEOur results suggest that avian influenza A virus of the H9N2 subtype likely made a recent contribution to the evolution of the H7N9 virus, a novel reassortant avian influenza virus A subtype, and continues to do so. The finding helps shed light on how the H7N9 virus emerged, spread, and transmitted to humans. It is of considerable interest for assessing the risk of the possible emergence of novel reassortant viruses with enhanced transmissibility to humans.

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Section: Discussionmentioning

confidence: 99%

Influenza H7N9 and H9N2 Viruses: Coexistence in Poultry Linked to Human H7N9 Infection and Genome Characteristics

Jin

Cui

et al. 2014

J Virol

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“…Previous study had shown that the percentage of H9N2 AIV possessing the PSRSSR↓GLF instead of PARSS-R↓GLF amino acid sequence motif in the HA cleavage site dramatically increased beginning in 2005, and the further investigation indicated that the A316S substitution at cleavage site of HA significantly strengthen the virulence of H9N2 AIV in chickens individually or combined with the 3-amino acid deletion in NA collectively (Sun Y et al 2013). Most of the lineage h9.4.2.5 viruses had the cleavage site motif PSRSSR↓GLF, while for the lineage h9.4.2.6, most viruses harbored PARSSR↓GLF between 2010 and 2013 based on previous studies (Chen et al 2013;Shen et al 2015). It is noteworthy that all of the H9N2 AIV isolated in this study between 2013 and 2015 harbored the A316S substitution at cleavage site.…”

Section: Discussionmentioning

confidence: 74%

“…Most of the viruses in lineages h9.4.2.1-h9.4.2.4 were isolated before 2007, while most of the H9N2 strains in lineages h9.4.2.5 and h9.4.2.6 were isolated after 2007. Furthermore, new lineage h9.4.2.6 existed mainly in South China, taken together, lineages h9.4.2.5 and h9.4.2.6 H9N2 AIV were the mainly prevalent virus subtype in chickens in China (Sun et al 2010;Jiang et al 2012;Zhang et al 2012;Chen et al 2013). Remarkably, the phylogenetic analysis of this study showed that all the 57 recent Chinese H9N2 AIV isolates belonged to lineage h9.4.2.5, indicating that the territorial range of h9.4.2.5 subtype H9N2 AIV continued to expand and became dominant.…”

Section: Discussionmentioning

confidence: 99%

“…In the mainland of China, H9N2 AIV was first detected from chickens in Guangdong in 1994, before that, H9N2 subtype AIV were isolated only from domestic ducks during influenza virus surveillance from 1976 to 1980 (Shortridge 1992;Liu et al 2003). Subsequently, the viruses spread to several other provinces and resulted in severe economic losses for poultry industries (Chen et al 2013). Currently, H9N2 viruses have become predominant AIV that are circulating in chickens in China (Xue et al 2014).…”

Section: Introductionmentioning

confidence: 99%

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Sequence and phylogenetic analysis of hemagglutinin genes of H9N2 influenza viruses isolated from chicken in China from 2013 to 2015

Xie

Liao

et al. 2016

Journal of Integrative Agriculture

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H9N2 avian influenza virus (AIV) infection is a major problem in poultry industry worldwide. In this study, molecular characterizations and phylogenetic relationships of hemagglutinin (HA) gene sequences of H9N2 AIV of 5 Chinese isolates in 2014 recently available in GenBank, 3 widely used vaccine strains, and 52 novel isolates in China from 2013 to 2015 were analyzed. The homology analysis showed that the nucleotide sequences of HA gene of these recent Chinese H9N2 AIV isolates shared homologies from 94.1 to 99.9%. Phylogenetic analysis showed that all isolates belonged to AIV lineage h9.4.2.5. Fifty-six out of the 57 recent Chinese H9N2 AIV isolates had the motifs PSRSSR↓GLF at the cleavage sites within the HA protein, while one isolate PWH01 harbored LSRSSR↓GLF. Remarkably, all of the recent Chinese H9N2 AIV strains had the Q216L substitution in the receptor binding site, which indicated that they had potential to infect humans. Most of recent Chinese H9N2 AIV isolates lost the potential N-linked glycosylation site at residues 200-202 compared with vaccine strains. This present study demonstrated that AIV lineage h9.4.2.5 was more predominant in China than other lineages as it harbored all the H9N2 AIV isolated between 2013 and 2015. Also we showed the importance of continuous surveillance of emerging H9N2 AIV in China and update of vaccine formulation accordingly in order to prevent and control H9N2 AIV.

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“…H9N2 viruses have prevailed in chickens in China in recent years and have constantly undergone reassortment, and novel genotypes have continued to emerge (1)(2)(3). A novel H7N9 reassortant subtype was recently found to cause severe human respiratory infections in China (4).…”

Section: Influenza Whole Inactivated Virus (Wiv) Is More Immunogenic mentioning

confidence: 99%

H9N2 Influenza Whole Inactivated Virus Combined with Polyethyleneimine Strongly Enhances Mucosal and Systemic Immunity after Intranasal Immunization in Mice

Qin¹,

Yin²,

Huang³

et al. 2015

Clin. Vaccine Immunol.

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Influenza whole inactivated virus (WIV) is more immunogenic and induces protective antibody responses compared with otherformulations, like split virus or subunit vaccines, after intranasal mucosal delivery. Polyethyleneimine (PEI), an organic polycation, is widely used as a reagent for gene transfection and DNA vaccine delivery. Although PEI recently has demonstrated potent mucosal adjuvant activity for viral subunit glycoprotein antigens, its immune activity with H9N2 WIV is not well demonstrated. Here, mice were immunized intranasally with H9N2 WIV combined with PEI, and the levels of local respiratory tract and systemic immune responses were measured. Compared to H9N2 WIV alone, antigen-specific IgA levels in the local nasal cavity, trachea, and lung, as well as levels of IgG and its subtypes (IgG1 and IgG2a) in the serum, were strongly enhanced with the combination. Similarly, the activation and proliferation of splenocytes were markedly increased. In addition, PEI is superior as an H9N2 WIV delivery system due to its ability to greatly increase the viral adhesion to mucosal epithelial cells and to enhance the cellular uptake and endosomal escape of antigens in dendritic cells (DCs) and further significantly activate DCs to mature. Taken together, these results provided more insights that PEI has potential as an adjuvant for H9N2 particle antigen intranasal vaccination.T he rise and spread of the low-pathogenic avian H9N2 influenza virus have seriously increased the risk of a new influenza pandemic. H9N2 viruses have prevailed in chickens in China in recent years and have constantly undergone reassortment, and novel genotypes have continued to emerge (1-3). A novel H7N9 reassortant subtype was recently found to cause severe human respiratory infections in China (4). Bioinformatic analyses for the H7N9 virus revealed that its six internal genes were from H9N2 avian influenza viruses of chickens (5). Thus, the elimination of low-pathogenic avian H9N2 influenza virus in poultry becomes even more important in influenza prevention.The nasal cavity of the respiratory tract is the primary entry site of the H9N2 influenza virus, and the viral infection could be discontinued if intranasal immunity is well established (6). Compared with live attenuated influenza vaccines or subunit influenza vaccines (such as purified viral hemagglutinin [HA]) or neuraminidase [NA]) proteins), whole inactivated H9N2 influenza vaccines have more advantages, including an improved safety profile, higher immunogenicity, more effective ability of establishing cross-protection at the pathogen's entry site, and stronger crosspresentation of antigens by dendritic cells (DCs) for a CD8 ϩ T cell response against viruses (7-9). However, mucosal immunization by intranasal delivery with inactivated virus alone is often poorly effective. Unlike systemic immunization, nasal antigens must cross various barriers (compact epithelium, mucociliary clearance, and mucus) before they contact with submucosal immune cells (10). Many researchers used various ...

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Genetic variation and phylogenetic analysis of hemagglutinin genes of H9 avian influenza viruses isolated in China during 2010–2012

Cited by 15 publications

References 32 publications

Influenza H7N9 and H9N2 Viruses: Coexistence in Poultry Linked to Human H7N9 Infection and Genome Characteristics

Influenza H7N9 and H9N2 Viruses: Coexistence in Poultry Linked to Human H7N9 Infection and Genome Characteristics

Sequence and phylogenetic analysis of hemagglutinin genes of H9N2 influenza viruses isolated from chicken in China from 2013 to 2015

H9N2 Influenza Whole Inactivated Virus Combined with Polyethyleneimine Strongly Enhances Mucosal and Systemic Immunity after Intranasal Immunization in Mice

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