The number of infected mammals in the UK has been revealed.
 
Newly released figures obtained by the BBC reveal that a total of nine mammal carcasses have tested positive for the H5N1 strain of avian influenza since 2021, including four red foxes and five Eurasian otters.

The locations of the animals range from the Shetland Islands in Scotland to Cornwall in England, with the most recent case occurring in Powys, Wales earlier this year. A total of 66 mammals have been tested.

It is thought that the cases are most likely to have been caused by scavenging on infected birds, rather than by transmission between mammals. 

Prof Ian Brown, director of scientific services at the APHA, told BBC News: "A sick or a dead wild bird contains an awful lot of virus. So scavenging mammals that will be opportunistic and predate on dead or sick birds will be exposed to very large quantities of virus. That gives a possibility for the virus to enter a host population that it doesn't normally maintain in.”

In response, Defra and the devolved governments are stepping up surveillance of the virus in mammals and will actively work to identify animals that might be scavenging on infected wild birds. Using genome analysis, it’s possible for researchers to tell whether the virus has spread from a bird or another mammal, allowing them to monitor how it is spreading.

Across the globe, a total of 119 mammals have tested positive for the virus, including seals, dolphins, and grizzly bears. There have also been outbreaks at mink farms in Spain and the USA. 

Prof Brown called for more international coordination to tackle the problem: "This global spread is a concern. We do need globally to look at new strategies, those international partnerships, to get on top of this disease. If we don't solve the problem across the globe, we're going to continue to have that risk."