Virulence determinants of high-pathogenic avian influenza viruses in gallinaceous poultry

In the field, highly pathogenic avian influenza viruses (HPAIV) originate from low-pathogenic strains of the haemagglutinin (HA) serotypes H5 and H7 that have acquired a polybasic HA cleavage site. This observation suggests the presence of a cryptic virulence potential of H5 and H7 low-pathogenic avian influenza viruses (LPAIV). Among all other LPAIV, the H9N2 strains are of particular relevance as they have become widespread across many countries in several avian species and have been transmitted to humans. To assess the potential of these strains to transform into an HPAIV, we introduced a polybasic cleavage site into the HA of a contemporary H9N2 isolate. Whereas the engineered polybasic HA cleavage site mutant remained a low-pathogenic strain like its parent virus, a reassortant expressing the modified H9 HA with engineered polybasic cleavage site and all the other genes from an H5N1 HPAIV became highly pathogenic in chicken with an intravenous pathogenicity index of 1.23. These results suggest that an HPAIV with a subtype other than H5 or H7 would only emerge under conditions where the HA gene could acquire a polybasic cleavage site and the other viral genes carry additional virulence determinants.

Download Full-text

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

Download Full-text

Detection of low pathogenic avian influenza viruses in wild birds in Castilla-La Mancha (south central Spain)

Veterinary Microbiology ◽

10.1016/j.vetmic.2010.05.008 ◽

2010 ◽

Vol 146 (3-4) ◽

pp. 200-208 ◽

Cited By ~ 29

Author(s):

Elisa Pérez-Ramírez ◽

Xeider Gerrikagoitia ◽

Marta Barral ◽

Ursula Höfle

Keyword(s):

Avian Influenza ◽

Wild Birds ◽

Influenza Viruses ◽

Avian Influenza Viruses ◽

Central Spain ◽

Pathogenic Avian Influenza ◽

South Central ◽

La Mancha ◽

Low Pathogenic Avian Influenza

Download Full-text

Detection of Low Pathogenic Avian Influenza Viruses in Wild Ducks from Canada: Comparison of Two Sampling Methods

Journal of Wildlife Diseases ◽

10.7589/0090-3558-47.2.466 ◽

2011 ◽

Vol 47 (2) ◽

pp. 466-470 ◽

Cited By ~ 8

Author(s):

E. Jane Parmley ◽

Catherine Soos ◽

André Breault ◽

Madeleine Fortin ◽

Emily Jenkins ◽

...

Keyword(s):

Avian Influenza ◽

Sampling Methods ◽

Influenza Viruses ◽

Avian Influenza Viruses ◽

Pathogenic Avian Influenza ◽

Low Pathogenic Avian Influenza

Download Full-text

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.

Download Full-text

Highly Pathogenic Avian Influenza Virus Infection of Mallards with Homo- and Heterosubtypic Immunity Induced by Low Pathogenic Avian Influenza Viruses

PLoS ONE ◽

10.1371/journal.pone.0006706 ◽

2009 ◽

Vol 4 (8) ◽

pp. e6706 ◽

Cited By ~ 76

Author(s):

Sasan R. Fereidouni ◽

Elke Starick ◽

Martin Beer ◽

Hendrik Wilking ◽

Donata Kalthoff ◽

...

Keyword(s):

Influenza Virus ◽

Avian Influenza ◽

Highly Pathogenic Avian Influenza ◽

Influenza Virus Infection ◽

Influenza Viruses ◽

Avian Influenza Viruses ◽

Highly Pathogenic ◽

Pathogenic Avian Influenza ◽

Heterosubtypic Immunity ◽

Pathogenic Avian Influenza Virus

Download Full-text

Genetic Characterization and Pathogenicity of H7N7 and H7N9 Avian Influenza Viruses Isolated from South Korea

Viruses ◽

10.3390/v13102057 ◽

2021 ◽

Vol 13 (10) ◽

pp. 2057

Author(s):

Eun-Jee Na ◽

Young-Sik Kim ◽

Yoon-Ji Kim ◽

Jun-Soo Park ◽

Jae-Ku Oem

Keyword(s):

Influenza Virus ◽

Avian Influenza ◽

South Korea ◽

Influenza Viruses ◽

The Body ◽

Avian Influenza Viruses ◽

Receptor Binding Site ◽

Phylogenetic Tree Analysis ◽

Pathogenic Avian Influenza ◽

Ha Gene

H7 low pathogenic avian influenza viruses (LPAIVs) can mutate into highly pathogenic avian influenza viruses (HPAIVs). In addition to avian species, H7 avian influenza viruses (AIVs) also infect humans. In this study, two AIVs, H7N9 (20X-20) and H7N7 (34X-2), isolated from the feces of wild birds in South Korea in 2021, were genetically analyzed. The HA cleavage site of the two H7 Korean viruses was confirmed to be ELPKGR/GLF, indicating they are LPAIVs. There were no amino acid substitutions at the receptor-binding site of the HA gene of two H7 Korean viruses compared to that of A/Anhui/1/2013 (H7N9), which prefer human receptors. In the phylogenetic tree analysis, the HA gene of the two H7 Korean viruses shared the highest nucleotide similarity with the Korean H7 subtype AIVs. In addition, the HA gene of the two H7 Korean viruses showed high nucleotide similarity to that of the A/Jiangsu/1/2018(H7N4) virus, which is a human influenza virus originating from avian influenza virus. Most internal genes (PB2, PB1, PA, NP, NA, M, and NS) of the two H7 Korean viruses belonged to the Eurasian lineage, except for the M gene of 34X-2. This result suggests that active reassortment occurred among AIVs. In pathogenicity studies of mice, the two H7 Korean viruses replicated in the lungs of mice. In addition, the body weight of mice infected with 34X-2 decreased 7 days post-infection (dpi) and inflammation was observed in the peribronchiolar and perivascular regions of the lungs of mice. These results suggest that mammals can be infected with the two H7 Korean AIVs. Our data showed that even low pathogenic H7 AIVs may infect mammals, including humans, as confirmed by the A/Jiangsu/1/2018(H7N4) virus. Therefore, continuous monitoring and pathogenicity assessment of AIVs, even of LPAIVs, are required.

Download Full-text