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# Korea's 2025-26 avian flu season carried diverse H5Nx genotypes, one of European origin
- URL: https://www.coios.me/korea-s-2025-26-avian-flu-season-carried-diverse-h5nx/
- Published: 2026-09-26T09:36:23.000Z
- Updated: 2026-09-26T10:34:23.000Z
- Description: Genomic surveillance of 62 poultry outbreaks and 63 wild bird detections in Korea during winter 2025-26 found extensive clade 2.3.4.4b reassortment, including the European H5N1 genotype EA-2024-DI.2.1 that spread across Europe in 2025, alongside novel H5N1 and H5N9 poultry genotypes.
- Author: Daniel Ryan
- Tags: Tomorrow's world, Infection and pandemics, South Korea, #peer-reviewed, #refines, #item, #source-2026-09

Researchers sequenced clade 2.3.4.4b H5N1, H5N6 and H5N9 viruses from 62 poultry outbreaks and 63 wild bird cases in Korea over winter 2025-26, and tested two isolates in chickens and ducks. Most genotypes were reassortants of East Asian H5N1 with low-pathogenicity wild bird viruses, and the European genotype EA-2024-DI.2.1 was also detected. H5N1 and H5N9 were highly infective in chickens (median lethal doses of 10^3.3 and 10^3.2 EID50); in young ducks H5N1 killed rapidly while H5N9 caused no mortality but still transmitted to all contact birds.

*Why it is interesting: A European H5N1 genotype reached East Asia within a season and reassorted locally, with H5N9 transmitting silently in ducks.*

Source

[Virus Research, 22 September 2026](https://doi.org/10.1016/j.virusres.2026.199807?ref=coios.me)

DOI

10.1016/j.virusres.2026.199807

Type

Peer-reviewed article

Design

Whole-genome surveillance of clade 2.3.4.4b H5Nx from 62 poultry outbreaks and 63 wild bird cases, Korea, winter 2025-26, with chicken and duck pathogenicity experiments

Verdict

Refines prior evidence

Driver

[Infection and pandemics](https://www.coios.me/d-infectious-disease/)