The Uncertain Picture in October
#18,960
A month ago, in A Robust Start To Avian Flu Season In Europe & North America, we looked at worrying signs that the recent trend in declining European HPAI outbreaks (see chart above) might be over, and that we could be on the verge of seeing a significant uptick in bird flu activity.
As early as August the UK reported an unexpected summer surge in H5N1 outbreaks in poultry farms, and by mid-September we were seeing similar trends reported in North America (see Canada & U.S. Report Early Fall Uptick In H5N1 Outbreaks In Poultry).Replacing the ? in my graphic of a month ago, we now have the first EFSA (European Food Safety Authority) assessment, which confirms that an `unprecedented' high level of HPAI has occurred in Europe in recent weeks.
The above graphic comes from the following 9-page report, published yesterday by the EFSA, which characterizes this as the fastest start to the fall HPAI season since at least 2016.
As we discussed last August, in H5Nx: Reassort & Repeat, the emergence of new genotypes of HPAI H5 is often associated with increased virulence and/or transmission of avian flu viruses.Not surprisingly, today's announcement contains confirmation that the bulk of the detections this fall in Europe are due to a new genotype DI.2.1 While we've yet to see a detailed phenotypic characterization of this variant, it appears to be the driving force behind this surge.
First, the abstract and some excerpts, followed by a statement from the EFSA. I'll have a bit more after the break.
Unprecedented high level of highly pathogenic avian influenza in wild birds in Europe during the 2025 autumn migration
Published: 24 November 2025
Documents
EFSA statement_HPAI_6 Sep-14 Nov
QUESTION NUMBER
EFSA-Q-2025-00661
CONTACT biohaw@efsa.europa.eu
Abstract
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.
© European Food Safety Authority
3. Results
During the current reporting period from 6 September to 14 November 2025, a total of1,443 HPAI virus detections in wild birds (with an HPAI virus detection potentially including more than one wild bird species) were reported in Europe. Compared to the same dates in previous years, this number was four times higher than in 2024, ten times higher than in 2023, twice as high as in 2022, and four times higher than in 2021 (Figure 1).
(SNIP)
Based on genetic data available so far, most of the HPAI A(H5N1) viruses identified were a variant of the previously circulating EA-2024-DI.2 genotype, which has mutated sufficiently to form a new sub-lineage, namely EA-2024.DI.2.1. Phylogenetic analysis indicates that this sub-lineage was probably newly introduced into Europe during autumn migration from the east and rapidly spread westward.
Avian influenza in Europe: enhanced surveillance and strict biosecurity needed as detections surge
Published: 24 November 2025
Last reviewed date: 25 November 2025
Between 6 September and 14 November 2025, 1,443 detections of highly pathogenic avian influenza (HPAI) A(H5) viruses were reported in wild birds across 26 European countries – four times higher than the same period in 2024 and the highest since at least 2016.
Waterfowl in various parts of Europe were heavily affected by HPAI during this period, including detections in apparently healthy wild birds, resulting in widespread environmental contamination. There were also high-mortality outbreaks in common cranes in Germany, France and Spain.
The vast majority of HPAI virus detections (99%) were reported as A(H5N1), and most were of a new variant of a previously circulating strain that was introduced into Europe from the east before rapidly spreading westward.
Among other measures, enhanced surveillance for early detection and robust biosecurity on farms are urgently required to prevent the introduction of HPAI in domestic birds and onward spread among poultry establishments.Recommended measures
Depending on their role, EFSA advises national, regional and local authorities, those involved in domestic poultry production and wild bird management, and those responsible for mammals at risk of avian influenza, to implement the following actions.Access the Bird Flu Radar here.
- Maintain high biosecurity in establishments keeping domestic birds, during both normal production and culling operations.
- Issue housing orders for domestic birds in areas with confirmed HPAI in wild birds or mass mortality events.
- Enhance surveillance in domestic birds to ensure early detection of infection in poultry establishments.
- Focus wild bird surveillance on wetland areas and migratory stopover sites within and outside Europe.
- Include wildlife rescue or rehabilitation centres in surveillance and ensure adequate biosecurity.
- Avoid artificial feeding of wild birds – especially cranes and swans – during high‑risk periods to reduce crowding and transmission risk.
- Remove wild bird carcasses promptly to reduce contamination of the environment with HPAI and prevent infection of other wild or domestic birds and mammals.
- Minimise disturbance of wild bird populations (e.g. hunting, leisure activities, drones) to limit further dispersal of the virus.
- Monitoring and awareness-raising tools EFSA’s Bird Flu Radar can be used to monitor the probability of the introduction of HPAI virus in wild bird populations in Europe over space and time.
In September 2025, EFSA and the European Commission published the #NoBirdFlu communication toolkit – practical, ready‑to‑use materials (posters, infographic, stickers, social media posts) available in all EU languages to support farmers and veterinarians in implementing biosecurity on poultry farms.
Access the toolkit here.
Links to science
Avian influenza
It is striking how often the world `unprecedented' crops up in avian flu reports;
an Unprecedented `Order Shift'
H5N1 clade 2.3.4.4b caused an unprecedented number of deaths among wild birds and poultry in numerous countries
A(H5N1) clade 2.3.4.4b has resulted in unprecedented impact to animal health
Most governments would rather ignore the threat, since its easier than dealing with it; and the public remains largely disinterested (see Two Surveys (UK & U.S.) Illustrating The Public's Lack of Concern Over Avian Flu).
