Isolation and genetic characterization of multiple genotypes of both H5 and H7 avian influenza viruses from environmental water in the Izumi plain, Kagoshima prefecture, Japan during the 2021/22 winter season

Okuya, Kosuke; Esaki, Mana; Tokorozaki, Kaori; Hasegawa, Taichi; Ozawa, Makoto

doi:10.1016/j.cimid.2024.102182

Cited by 3 publications

(2 citation statements)

References 25 publications

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“…In the 2020/21 winter, a reassortant H5N8 HPAIV containing the PA gene derived from LPAIVs found at the same location was reported to emerge at another wintering site in Japan [22]. Our findings and those of Okuya et al [24] indicate that novel gene reassortment events of AIVs can emerge not only in northern nesting areas of migratory water birds, but also at overwintering sites of migratory birds. Every winter, influenza virus is brought to the island nation of Japan along with the migration of birds.…”

Section: Discussionsupporting

confidence: 70%

“…In this study, we surveyed environmental water and fecal samples for AIVs at a wintering site of migratory waterfowls in Tottori, Japan, during the winter and spring migration [18] of one season (December 2021 to March 2022) and isolated HPAIV A/water/Tottori/NK1201-2/2021 (H5N8) (NK1201) [19]. Recently, various genotypes of H5Nx clade 2.3.4.4b HPAIVs [19][20][21][22][23][24] and H7N7 LPAIVs [24] have been detected in Japan. H5N8 and H5N1 HPAIVs isolated in the 20221-2022 winter season in Japan were divided into three groups (G2a, G2b, and G2d) based on their HA gene sequences [19].…”

Section: Introductionmentioning

confidence: 99%

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Novel Genotype of HA Clade 2.3.4.4b H5N8 Subtype High Pathogenicity Avian Influenza Virus Emerged at a Wintering Site of Migratory Birds in Japan, 2021/22 Winter

Mihiretu,

Usui,

Kiyama

et al. 2024

Pathogens

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Surveillance of avian influenza virus (AIV) was conducted in the 2021–2022 winter season at a wintering site of migratory Anatidae in Japan. An H5N8 subtype high pathogenicity AIV (HPAIV) with a unique gene constellation and four low pathogenicity AIVs (LPAIVs) were isolated from environmental samples. The genetic origin of the HPAIV (NK1201) was determined with whole-genome sequencing and phylogenetic analyses. Six of NK1201’s eight genes were closely related to HA clade 2.3.4.4b H5N8 subtype HPAIVs, belonging to the G2a group, which was responsible for outbreaks in poultry farms in November 2021 in Japan. However, the remaining two genes, PB1 and NP, most closely matched those of the LPAIVs H7N7 and H1N8, which were isolated at the same place in the same 2021–2022 winter. No virus of the NK1201 genotype had been detected prior to the 2021–2022 winter, indicating that it emerged via genetic reassortment among HPAIV and LPAIVs, which were prevalent at the same wintering site. In addition, experimental infection in chickens indicated that NK1201 had slightly different infectivity compared to the reported infectivity of the representative G2a group H5N8 HPAIV, suggesting that the PB1 and NP genes derived from LPAIVs might have affected the pathogenicity of the virus in chickens. Our results directly demonstrate the emergence of a novel genotype of H5N8 HPAIV through gene reassortment at a wintering site. Analyses of AIVs at wintering sites can help to identify the emergence of novel HPAIVs, which pose risks to poultry, livestock, and humans.

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Section: Discussionsupporting

confidence: 70%

Section: Introductionmentioning

confidence: 99%

Novel Genotype of HA Clade 2.3.4.4b H5N8 Subtype High Pathogenicity Avian Influenza Virus Emerged at a Wintering Site of Migratory Birds in Japan, 2021/22 Winter

Mihiretu,

Usui,

Kiyama

et al. 2024

Pathogens

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Phylogenetic Characterization of Novel Reassortant 2.3.4.4b H5N8 Highly Pathogenic Avian Influenza Viruses Isolated from Domestic Ducks in Egypt During the Winter Season 2021–2022

Saad,

Esaki,

Kojima

et al. 2024

Viruses

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Avian influenza (AI) is an extremely contagious viral disease of domestic and wild birds that can spread rapidly among bird populations, inducing serious economic losses in the poultry industry. During the winter season 2021–2022, we isolated seventeen highly pathogenic avian influenza (HPAI) H5N8 viruses from outbreaks involving ducks in Egypt, occurring in both backyard and farm settings. The aim of this study was to pinpoint genetic key substitutions (KSs) that could heighten the risk of a human pandemic by influencing the virus’s virulence, replication ability, host specificity, susceptibility to drugs, or transmissibility. To understand their evolution, origin, and potential risks for a human pandemic, whole-genome sequencing and phylogenetic analysis were conducted. Our analysis identified numerous distinctive mutations in the Egyptian H5N8 viruses, suggesting potential enhancements in virulence, resistance to antiviral drugs, and facilitation of transmission in mammals. In this study, at least five genotypes within one genome constellation of H5N8 viruses were identified, raising concerns about the potential emergence of novel viruses with altered characteristics through reassortment between different genotypes and distinct groups. These findings underscore the role of ducks in the virus’s evolutionary process and emphasize the urgent need for enhanced biosecurity measures in domestic duck farms to mitigate pandemic risk.

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Phylogenetic and Pathogenic Analysis of H5N1 and H5N6 High Pathogenicity Avian Influenza Virus Isolated from Poultry Farms (Layer and Broiler Chickens) in Japan in the 2023/2024 Season

Nishiura,

Kumagai,

Mine

et al. 2024

Viruses

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During the 2023–2024 winter, 11 high pathogenicity avian influenza (HPAI) outbreaks caused by clade 2.3.4.4b H5N1 and H5N6 HPAI viruses were confirmed in Japanese domestic poultry among 10 prefectures (n = 10 and 1, respectively). In this study, we aimed to genetically and pathologically characterize these viruses. Phylogenetic analysis revealed that H5N1 viruses were classified into the G2d-0 genotype, whereas the H5N6 virus was a novel genotype in Japan, designated as G2c-12. The G2c-12 virus shared PB2, PB1, PA, HA, and M genes with previous G2c viruses, but had NP and NS genes originating from avian influenza viruses in wild birds abroad. The N6 NA gene was derived from an H5N6 HPAI virus that was different from the viruses responsible for the outbreaks in Japan in 2016–2017 and 2017–2018. Experimental infections in chickens infected with H5N1(G2d-0) and H5N6(G2c-12) HPAI viruses showed no significant differences in the 50% chicken lethal dose, mean death time, or virus shedding from the trachea and cloaca, or in the histopathological findings. Different genotypes of the viruses worldwide, their introduction into the country, and their stable lethality in chickens may have triggered the four consecutive seasons of HPAI outbreaks in Japan.

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Isolation and genetic characterization of multiple genotypes of both H5 and H7 avian influenza viruses from environmental water in the Izumi plain, Kagoshima prefecture, Japan during the 2021/22 winter season

Cited by 3 publications

References 25 publications

Novel Genotype of HA Clade 2.3.4.4b H5N8 Subtype High Pathogenicity Avian Influenza Virus Emerged at a Wintering Site of Migratory Birds in Japan, 2021/22 Winter

Novel Genotype of HA Clade 2.3.4.4b H5N8 Subtype High Pathogenicity Avian Influenza Virus Emerged at a Wintering Site of Migratory Birds in Japan, 2021/22 Winter

Phylogenetic Characterization of Novel Reassortant 2.3.4.4b H5N8 Highly Pathogenic Avian Influenza Viruses Isolated from Domestic Ducks in Egypt During the Winter Season 2021–2022

Phylogenetic and Pathogenic Analysis of H5N1 and H5N6 High Pathogenicity Avian Influenza Virus Isolated from Poultry Farms (Layer and Broiler Chickens) in Japan in the 2023/2024 Season

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