24 March 2025
Influenza of avian origin (H5N1) has been detected in a sheep in England. The case was identified following routine surveillance of farmed livestock on a premises in Yorkshire where highly pathogenic avian influenza (H5N1) had been confirmed in other captive birds. The ewe tested positive for H5 antibodies in the blood, and her milk was positive for H5 RNA by polymerase chain reaction (PCR). The ewe had been showing clinical signs of mastitis.

All affected birds and the infected ewe were humanely culled to mitigate the risk of further disease spread. Further official testing of the remaining flock of sheep at the premises, including the lambs of the affected ewe, were negative for the presence of avian influenza virus.

While this is the first time avian influenza virus has been detected in a sheep, it is not the first time influenza of avian origin has been detected in livestock in other countries. There is no evidence to suggest an increased risk to the nation’s livestock population.

The case definition for influenza of avian origin has been updated and provides further guidance on how and when to report suspicion in mammals.