Rapid Emergence of the Reassortant 2.3.4.4b H5N2 Highly Pathogenic Avian Influenza Viruses in a Live Poultry Market in Xinjiang, Northwest China

ABSTRACT The genesis of novel influenza viruses through reassortment poses a continuing risk to public health. This is of particular concern in Bangladesh, where highly pathogenic avian influenza viruses of the A(H5N1) subtype are endemic and cocirculate with other influenza viruses. Active surveillance of avian influenza viruses in Bangladeshi live poultry markets detected three A(H5) genotypes, designated H5N1-R1, H5N1-R2, and H5N2-R3, that arose from reassortment of A(H5N1) clade 2.3.2.1a viruses. The H5N1-R1 and H5N1-R2 viruses contained HA, NA, and M genes from the A(H5N1) clade 2.3.2.1a viruses and PB2, PB1, PA, NP, and NS genes from other Eurasian influenza viruses. H5N2-R3 viruses contained the HA gene from circulating A(H5N1) clade 2.3.2.1a viruses, NA and M genes from concurrently circulating A(H9N2) influenza viruses, and PB2, PB1, PA, NP, and NS genes from other Eurasian influenza viruses. Representative viruses of all three genotypes and a parental clade 2.3.2.1a strain (H5N1-R0) infected and replicated in mice without prior adaptation; the H5N2-R3 virus replicated to the highest titers in the lung. All viruses efficiently infected and killed chickens. All viruses replicated in inoculated ferrets, but no airborne transmission was detected, and only H5N2-R3 showed limited direct-contact transmission. Our findings demonstrate that although the A(H5N1) viruses circulating in Bangladesh have the capacity to infect and replicate in mammals, they show very limited capacity for transmission. However, reassortment does generate viruses of distinct phenotypes. IMPORTANCE Highly pathogenic avian influenza A(H5N1) viruses have circulated continuously in Bangladesh since 2007, and active surveillance has detected viral evolution driven by mutation and reassortment. Recently, three genetically distinct A(H5N1) reassortant viruses were detected in live poultry markets in Bangladesh. Currently, we cannot assign pandemic risk by only sequencing viruses; it must be conducted empirically. We found that the H5Nx highly pathogenic avian influenza viruses exhibited high virulence in mice and chickens, and one virus had limited capacity to transmit between ferrets, a property considered consistent with a higher zoonotic risk.

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Novel reassortant 2.3.4.4B H5N6 highly pathogenic avian influenza viruses circulating among wild, domestic birds in Xinjiang, Northwest China

Journal of Veterinary Science ◽

10.4142/jvs.2021.22.e43 ◽

2021 ◽

Vol 22 ◽

Author(s):

Qian Zhang ◽

Xindi Mei ◽

Cheng Zhang ◽

Juan Li ◽

Nana Chang ◽

...

Keyword(s):

Avian Influenza ◽

Highly Pathogenic Avian Influenza ◽

Northwest China ◽

Influenza Viruses ◽

Avian Influenza Viruses ◽

Highly Pathogenic ◽

Pathogenic Avian Influenza ◽

Domestic Birds

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Domestic ducks play a major role in the maintenance and spread of H5N8 highly pathogenic avian influenza viruses in South Korea

Transboundary and Emerging Diseases ◽

10.1111/tbed.13406 ◽

2019 ◽

Vol 67 (2) ◽

pp. 844-851 ◽

Cited By ~ 5

Author(s):

Jung‐Hoon Kwon ◽

Justin Bahl ◽

David E. Swayne ◽

Yu‐Na Lee ◽

Youn‐Jeong Lee ◽

...

Keyword(s):

Avian Influenza ◽

South Korea ◽

Highly Pathogenic Avian Influenza ◽

Influenza Viruses ◽

Avian Influenza Viruses ◽

Domestic Ducks ◽

Highly Pathogenic ◽

Pathogenic Avian Influenza

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Opposite outcomes of the within-host competition between highly and low pathogenic H5N8 avian influenza viruses in chickens compared to ducks

Journal of Virology ◽

10.1128/jvi.01366-21 ◽

2021 ◽

Author(s):

Pierre Bessière ◽

Thomas Figueroa ◽

Amelia Coggon ◽

Charlotte Foret-Lucas ◽

Alexandre Houffschmitt ◽

...

Keyword(s):

Avian Influenza ◽

Reverse Genetics ◽

Highly Pathogenic Avian Influenza ◽

Viral Evolution ◽

Influenza Viruses ◽

Poultry Production ◽

Avian Influenza Viruses ◽

Highly Pathogenic ◽

Pathogenic Avian Influenza ◽

Low Pathogenic Avian Influenza

Highly pathogenic avian influenza viruses (HPAIV) emerge from low pathogenic avian influenza viruses (LPAIV) through the introduction of basic amino acids at the hemagglutinin (HA) cleavage site. Following viral evolution, the newly formed HPAIV likely represents a minority variant within the index host, predominantly infected with the LPAIV precursor. Using reverse-genetics engineered H5N8 viruses differing solely at the HA cleavage, we tested the hypothesis that the interaction between the minority HPAIV and the majority LPAIV could modulate the risk of HPAIV emergence and that the nature of the interaction could depend on the host species. In chickens, we observed that the H5N8 LP increased H5N8 HP replication and pathogenesis. By contrast, the H5N8 LP antagonized H5N8 HP replication and pathogenesis in ducks. Ducks mounted a more potent antiviral innate immune response than chickens against the H5N8 LP , which correlated with H5N8 HP inhibition. These data provide experimental evidence that HPAIV may be more likely to emerge in chickens than in ducks and underscore the importance of within-host viral variants interactions in viral evolution. IMPORTANCE Highly pathogenic avian influenza viruses represent a threat to poultry production systems and to human health because of their impact on food security and because of their zoonotic potential. It is therefore crucial to better understand how these viruses emerge. Using a within-host competition model between highly and low pathogenic avian influenza viruses, we provide evidence that highly pathogenic avian influenza viruses could be more likely to emerge in chickens than in ducks. These results have important implications for highly pathogenic avian influenza virus emergence prevention and they underscore the importance of within-host viral variants interactions in virus evolution.

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