Evidence map›Paper›PMID 42446198›Full record

ArticleMicrobiology spectrum2026

High pathogenicity avian influenza A (H5N1) viruses isolated from poultry and wild birds in Japan during the 2024-2025 season.

Yoshihiro Takadate, Hayate Nishiura, Asuka Kumagai, Junki Mine, Ryota Tsunekuni, Saki Sakuma, Kosuke Soda, Mana Esaki, Kosuke Okuya, Kei Nabeshima and 9 more

Abstract read
In one paragraph

Article in Microbiology spectrum, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

0numbers the graph read from it
0cells of the map it votes in
0citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

0 citing papers in PubMed.

No citing paper in PubMed yet.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

19 authors.

Yoshihiro Takadate *Emerging Virus Group, Division of Zoonosis Research, National Institute of Animal Health, National Agriculture and Food Research Organization, Tsukuba, Ibaraki, Japan.ORCID 0009-0000-5132-1988
Hayate Nishiura *Emerging Virus Group, Division of Zoonosis Research, National Institute of Animal Health, National Agriculture and Food Research Organization, Tsukuba, Ibaraki, Japan.ORCID 0000-0002-0882-4165
Asuka KumagaiEmerging Virus Group, Division of Zoonosis Research, National Institute of Animal Health, National Agriculture and Food Research Organization, Tsukuba, Ibaraki, Japan.
Junki MineEmerging Virus Group, Division of Zoonosis Research, National Institute of Animal Health, National Agriculture and Food Research Organization, Tsukuba, Ibaraki, Japan.
Ryota TsunekuniEmerging Virus Group, Division of Zoonosis Research, National Institute of Animal Health, National Agriculture and Food Research Organization, Tsukuba, Ibaraki, Japan.
Saki SakumaEmerging Virus Group, Division of Zoonosis Research, National Institute of Animal Health, National Agriculture and Food Research Organization, Tsukuba, Ibaraki, Japan.
Kosuke SodaAvian Infectious Disease and Global Health Research Center, Tottori University, Tottori, Japan.
Mana EsakiJoint Graduate School of Veterinary Science, Kagoshima University, Kagoshima, Japan.ORCID 0009-0001-3440-2687
Kosuke OkuyaJoint Faculty of Veterinary Medicine, Kagoshima University, Kagoshima, Japan.ORCID 0000-0002-7987-9884
Kei NabeshimaBiodiversity Division, National Institute for Environmental Studies, Tsukuba, Japan.
Takahiro HionoLaboratory of Microbiology, Department of Disease Control, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan.ORCID 0000-0001-8897-3592
Hiroki TakakuwaFaculty of Life Sciences, Kyoto Sangyo University, Kyoto, Japan.
Tatsufumi UsuiAvian Infectious Disease and Global Health Research Center, Tottori University, Tottori, Japan.
Makoto OzawaJoint Graduate School of Veterinary Science, Kagoshima University, Kagoshima, Japan.ORCID 0000-0002-7731-5321
Manabu OnumaBiodiversity Division, National Institute for Environmental Studies, Tsukuba, Japan.
Norikazu IsodaLaboratory of Microbiology, Department of Disease Control, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan.
Yoshihiro SakodaLaboratory of Microbiology, Department of Disease Control, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan.ORCID 0000-0001-7021-1688
Yuko UchidaEmerging Virus Group, Division of Zoonosis Research, National Institute of Animal Health, National Agriculture and Food Research Organization, Tsukuba, Ibaraki, Japan.
Kohtaro MiyazawaEmerging Virus Group, Division of Zoonosis Research, National Institute of Animal Health, National Agriculture and Food Research Organization, Tsukuba, Ibaraki, Japan.ORCID 0000-0002-0318-7275

Funding

Japan Agency for Medical Research and Development JP223fa627005, JP24wm000125008Ministry of Agriculture, Forestry and Fisheries JPJ008617.23812859
6 · The paper itself

Abstract

H5N1 high pathogenicity avian influenza (HPAI) viruses of clade 2.3.4.4b continue to spread globally among wild birds and poultry, and diversify through gene reassortment. Since 2024, spillovers of H5N1 viruses have been reported in dairy cattle in the United States. Given the numerous HPAI outbreaks in poultry and wild birds in Japan during the 2024-2025 season, we aimed to examine the genetic diversity, pathogenicity, and host range of these viruses. Phylogenetic analyses revealed that all viruses in the 2024-2025 season belonged to G2d and G2c subgroups in clade 2.3.4.4b and were divided into 11 genotypes (G2d: six genotypes, G2c: five genotypes). Of these, G2d-0 was the dominant genotype in both poultry and wild birds. Novel genotypes emerged through reassortment between G2d and G2c viruses. Experimental infection of chickens revealed comparable pathogenicity among genotypes, although the amounts of viral shedding were high in chickens inoculated with G2d-0 and G2c-13 viruses, which were genotypes confirmed in multiple outbreaks in the 2024-2025 season, suggesting high transmission potential. IMPORTANCE: H5N1 high pathogenicity avian influenza (HPAI) viruses have spread in poultry and wild birds worldwide. H5N1 viruses have also spread in dairy cattle in the United States since 2024. Japan reported numerous HPAI cases during the 2024-2025 season. Herein, phylogenetic analyses using strains isolated from poultry and wild birds enabled a detailed investigation of their genetic backgrounds, which is essential for elucidating introduction routes and evolution. Investigation of pathogenicity may help predict the outbreak frequency. This study revealed that HPAI viruses of multiple genotypes had been introduced into Japan, and chickens infected with genotypes detected from continuous outbreaks exhibited high virus shedding. In addition, comparing infectivity in bovine cells revealed the risk of cattle infection. H5N1 infection had not been reported in cattle in Japan, and our results suggest that the risk remains low. These integrated analyses provide key insights for developing effective strategies against HPAI outbreaks.

Indexed as

Animals, WildBirdsInfluenza A Virus, H5N1 SubtypeInfluenza in BirdsAnimalsCattleChickensDisease OutbreaksGenetic VariationGenotypeJapanPhylogenyPoultrySeasonsVirulence2024-2025 seasonbovine mammary epithelial cellsH5N1high pathogenicity avian influenza virusJapanpathogenic analysisphylogenetic analysispoultrywild birds

Identifiers

PMID42446198
PMCPMC13435830

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.