Scores of bird flu outbreaks have been reported this autumn and winter, with a highly infectious strain forcing thousands of birds into lockdown. There have been 92 outbreaks of Highly Pathogenic Asian Influenza since October, surpassing the previous year’s total of 82 (October 2024 to September 2025), according to data from the UK Health Security Agency.
Bird flu is spread through the saliva, mucus and faeces of infected birds and can cause severe respiratory illness. One of Britain’s leading virologists and a group leader in avian virology at The Pirbright Institute, Professor Ian Brown, warned in November that farmers should be “prepared for the worst” with this “super-infectious” strain.
He told the BBC: “We had a very, very serious epidemic between 2021 and 2023 — in excess of 350 outbreaks in the UK. That’s off the scale.
“Now, it’s really, really difficult to state what the final size of this outbreak would be, but the early signals are not great.”
There have been a handful of sporadic cases of bird flu infecting humans in the UK, but the risk to the general public is considered very low.
However, the virus is considered to have pandemic potential if it mutates to become more easily transmissible.
Outbreaks among wild birds and poultry also cause mass mortality and severe economic losses for affected farmers. The virus was also recently found to have infected dairy cattle in the US.
A three-year international research project was launched last month to address the escalating global threat.
Researchers will analyse the virus in detail and investigate how it can replicate in animals such as cows. They will also assess livestock immune responses and evaluate vaccine platforms.
Prof Brown, project lead at The Pirbright Institute, said: “Current threat levels from H5 avian influenza viruses in the UK and Europe are high, and the possibility of spread to livestock species such as dairy cattle and pigs cannot be excluded.
“Our work will focus on evaluating vaccination strategies as emergency interventions and assessing immune responses to inform the future use of available vaccines.”