Detection of H5N1 High Pathogenicity Avian Influenza Viruses in Four Raptors and Two Geese in Japan in the Fall of 2022
Kei Nabeshima,
Yoshihiro Takadate,
Kosuke Soda,
Takahiro Hiono,
Norikazu Isoda,
Yoshihiro Sakoda,
Junki Mine,
Kohtaro Miyazawa,
Manabu Onuma,
Yuko Uchida
Affiliations
Kei Nabeshima
Biodiversity Division, Ecological Risk Assessment and Control Section, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba 305-8506, Ibaraki, Japan
Yoshihiro Takadate
Emerging Virus Group, Division of Zoonosis Research, National Institute of Animal Health, 3-1-5 Kannondai, Tsukuba 305-0856, Ibaraki, Japan
Kosuke Soda
Avian Zoonosis Research Center, Faculty of Agriculture, Tottori University, Tottori 680-8553, Tottori, Japan
Takahiro Hiono
Laboratory of Microbiology, Department of Disease Control, Faculty of Veterinary Medicine, Hokkaido University, Sapporo 060-0818, Hokkaido, Japan
Norikazu Isoda
Laboratory of Microbiology, Department of Disease Control, Faculty of Veterinary Medicine, Hokkaido University, Sapporo 060-0818, Hokkaido, Japan
Yoshihiro Sakoda
Laboratory of Microbiology, Department of Disease Control, Faculty of Veterinary Medicine, Hokkaido University, Sapporo 060-0818, Hokkaido, Japan
Junki Mine
Emerging Virus Group, Division of Zoonosis Research, National Institute of Animal Health, 3-1-5 Kannondai, Tsukuba 305-0856, Ibaraki, Japan
Kohtaro Miyazawa
Emerging Virus Group, Division of Zoonosis Research, National Institute of Animal Health, 3-1-5 Kannondai, Tsukuba 305-0856, Ibaraki, Japan
Manabu Onuma
Biodiversity Division, Ecological Risk Assessment and Control Section, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba 305-8506, Ibaraki, Japan
Yuko Uchida
Emerging Virus Group, Division of Zoonosis Research, National Institute of Animal Health, 3-1-5 Kannondai, Tsukuba 305-0856, Ibaraki, Japan
In the fall of 2022, high pathogenicity avian influenza viruses (HPAIVs) were detected from raptors and geese in Japan, a month earlier than in past years, indicating a shift in detection patterns. In this study, we conducted a phylogenetic analysis on H5N1 HPAIVs detected from six wild birds during the 2022/2023 season to determine their genetic origins. Our findings revealed that these HPAIVs belong to the G2 group within clade 2.3.4.4b, with all isolates classified into three subgroups: G2b, G2d, and G2c. The genetic background of the G2b virus (a peregrine falcon-derived strain) and G2d viruses (two raptors and two geese-derived strains) were the same as those detected in Japan in the 2021/2022 season. Since no HPAI cases were reported in Japan during the summer of 2022, it is probable that migratory birds reintroduced the G2b and G2d viruses. Conversely, the G2c virus (a raptor-derived strain) was first recognized in Japan in the fall of 2022. This strain might share a common ancestor with HPAIVs from Asia and West Siberia observed in the 2021/2022 season. The early migration of waterfowl to Japan in the fall of 2022 could have facilitated the early invasion of HPAIVs.
