Phylogenetic analysis and pathogenicity of H3 subtype avian influenza viruses isolated from live poultry markets in China.

Hongrui Cui,Jianmei Yang,Qinfang Liu,Zejun Li,Tao Ruan,Qiaoyang Teng,Xuesong Li,Hongjun Chen,Ying Shi

doi:10.1038/srep27360

Hongrui Cui, Jianmei Yang + Show 7 more

Open Access

https://doi.org/10.1038/srep27360

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Abstract

H3 subtype influenza A virus is one of the main subtypes that threats both public and animal health. However, the evolution and pathogenicity of H3 avian influenza virus (AIV) circulating in domestic birds in China remain largely unclear. In this study, seven H3 AIVs (four H3N2 and three H3N8) were isolated from poultry in live poultry market (LPM) in China. Phylogenetic analyses of full genomes showed that all viruses were clustered into Eurasian lineage, except N8 genes of two H3N8 isolates fell into North American lineage. Intriguingly, the N8 gene of one H3N8 and PB2, PB1, NP and NS of two H3N2 isolates have close relationship with those of the highly pathogenic H5N8 viruses circulating in Korea and United States, suggesting that the H3-like AIV may contribute internal genes to the highly pathogenic H5N8 viruses. Phylogenetic tree of HA gene and antigenic cross-reactivity results indicated that two antigenically different H3 viruses are circulating in LPM in China. Most of the H3 viruses replicated in mice lung and nasal turbinate without prior adaptation, and the representative H3 viruses infected chickens without causing clinical signs. The reassortment of H3 subtype influenza viruses warrants continuous surveillance in LPM in China.

Highlights

Influenza virus was isolated in domestic duck in China
Sequence analysis showed that this novel H3N2 contains genes from H7N3, and H7N7 viruses that had close relationship with H7N9 virus, which suggested that reassortment occurred between H3N2 with other subtype influenza viruses[25]
B854-2/H3N8 virus was isolated from chicken and all the others were from ducks

Summary

Introduction

Influenza virus was isolated in domestic duck in China. In China, live poultry markets are served as slaughterhouses in which chickens, ducks, quails, guineafowl, and pigeons etc. Comingling of different poultry species makes live poultry market a major source of AIV dissemination, reassortment and interspecies transmission[26]. Multiple subtype influenza viruses in LPM enhance the reassortment possibility. The evolution and reassortant situation of H3 subtype influenza virus in LPM remain unclear. Seven H3 subtype AIV strains (four H3N2 and three H3N8) were isolated from domestic ducks and chickens in LPM in China. To better understand the evolution of these H3 influenza viruses, the full genomes of the H3 AIVs were sequenced and analyzed. Phylogenic analyses of all eight segments were conducted and the pathogenicity of these isolates in mice and chickens were evaluated

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Conclusion