open access

https://hdl.handle.net/2115/94295

Continuous Introduction of H5 High Pathogenicity Avian Influenza Viruses in Hokkaido, Japan: Characterization of Viruses Isolated in Winter 2022-2023 and Early Winter 2023-2024

英語

2024-03-14

Wiley-Hindawi

Transboundary and emerging diseases

2024

1199876

High pathogenicity avian influenza (HPAI) has impacted poultry and wild birds globally. The number of H5 HPAI virus (HPAIV) infection cases in wild birds in Hokkaido (Northern Japan) was high in the last two seasons, contributing to virus spillover to resident birds and poultry. Therefore, H5 HPAIVs in birds and mammals in Hokkaido in winter 2022-2023 and 2023-2024 were monitored and viruses were phylogenetically, antigenically, and pathogenetically characterized. Thirty HPAIV isolates were subtyped and pathotyped by sequencing the hemagglutinin (HA) gene of viruses. Phylogenetic analysis of the HA gene revealed that all isolated HPAIVs were categorized into clade 2.3.4.4b and divided into three groups (G2b, G2c, and G2d). Most isolates belonging to subgroup G2d clustered with isolates in winter 2021-2022 in Hokkaido. The other isolates were categorized into two subgroups, G2b and G2c, mainly composed of isolates in Honshu Island in winter 2021-2022 and 2022-2023, respectively. Two H5 HPAIVs isolated in Eastern Russia in spring and autumn 2022 were genetically close to most Hokkaido isolates (G2d), and a virus isolated in Hokkaido in November 2023 was also grouped in subgroup G2d. Further analysis of all eight gene segments identified six types of gene constellations. Cross-hemagglutination inhibition test indicated that the antigenicity of H5 HPAIVs isolated in the last several seasons was similar within them but slightly different from that in the 2010s. Three chicken breeds were intranasally challenged with four representative isolates to assess their pathogenicity. All chickens except one broiler chicken were dead until 5-day postchallenge with different pathogenicity of these viruses. The pathogenicity of one HPAIV strain was significantly lower in broiler chickens than in layer chickens. The mixture of multiple characteristics of HPAIVs in Hokkaido was confirmed by bird migration routes. Thus, many HPAIVs can be brought and scattered anywhere on Earth.

学術雑誌論文

Accepted Manuscript

This is the peer reviewed version of the following article: Continuous Introduction of H5 High Pathogenicity Avian Influenza Viruses in Hokkaido, Japan: Characterization of Viruses Isolated in Winter 2022-2023 and Early Winter 2023-2024, which has been published in final form at 10.1155/2024/1199876. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. This article may not be enhanced, enriched or otherwise transformed into a derivative work, without express permission from Wiley or by statutory rights under applicable legislation. Copyright notices must not be removed, obscured or modified. The article must be linked to Wiley’s version of record on Wiley Online Library and any embedding, framing or otherwise making available the article or pages thereof by third parties from platforms, services and websites other than Wiley Online Library must be prohibited.

1865-1674