Unprecedented high level of highly pathogenic avian influenza in wild birds in Europe during the 2025 autumn migration.

Between 6 September and 14 November 2025, 1,443 highly pathogenic avian influenza (HPAI) A(H5) virus detections were reported in wild birds across 26 countries in Europe. This number was four times higher than in the same period in 2024 and the highest overall for those weeks since at least 2016. Almost all the detections (99%) were due to HPAI A(H5N1) viruses, and most of them belonged to EA-2024-DI.2.1, a new sub-lineage of the EA-2024-DI.2 genotype. These HPAI virus detections in wild birds involved increasing numbers of waterfowl species (ducks, geese and swans) that were found positive in large parts of Europe. In addition, high numbers of common cranes were affected across a wide band stretching from northeast to southwest Europe. Given the unprecedented high circulation of HPAI virus in the wild bird population compared to previous years, and the associated high environmental contamination, strict biosecurity measures and early detection of infected poultry establishments are urgently needed to prevent introductions from wild to domestic birds and further spread among poultry establishments. Prompt removal of wild bird carcasses is indicated to reduce the risk of infection for other wild and domestic birds and mammals.