The UK is still “a long way” from being in a situation where bird flu could infect humans and spread in a similar way to Covid-19, an expert from the Animal and Plant Health Agency (Apha) has said.

Professor Ian Brown, scientific services director, was speaking after the news that otters and foxes have been found in the UK with avian flu, writes Jane Kirby, PA Health and Science Editor.

Last September two foxes were found infected with bird flu in Cornwall.

New figures released by the Government earlier this week show that nine mammals in total have been discovered with bird flu since December 2021.

These are a fox in Durham, one in Cheshire East and another in Powys and two otters in Fife, one in the Shetland Islands and one on the Isle of Skye. 

The animals are believed to have eaten dead wild birds that were infected with the virus.

Health officials have said the risk to the public is low, although Professor Brown from Apha told BBC Radio 4’s Today programme there was evidence that the flu had now jumped to other species.

He said: “We’ve recently detected events both here and around the world, evidence that this virus can on certain occasions jump into other species.

“To be clear though, this is still a bird virus essentially, that wants to be in birds.

“These are wild mammals, animals that scavenge on sick and dead birds, and there’s a lot of dead wild birds at the moment due to the bird flu presence around the globe, and those animals are consuming and being exposed to very high quantities of virus and that’s leading to some spillover infection.

“What we don’t have any evidence of is that it can then go from fox to fox or otter to otter, so these are what we call dead-end infections.”

Asked about potential spread to humans, he said: “We need to understand the consequence of this infection. Does it make the virus change by jumping its host? We’re aware those events can sometimes lead to that.”

Asked whether there was a possibility that bird flu could become a virus that infects humans like Covid-19, he said: “At the moment, we’re a long way from that.

“We’ve seen this jump, we’ve not seen maintenance in a mammalian species and, importantly, we haven’t seen a succession of changes in the virus that tell us it’s moving more towards a virus that can infect humans.

“This still is a spillover, but we need to be watchful, which is why we’re doing the surveillance.”

The UK Health Security Agency (UKHSA) warned that the “rapid and consistent acquisition of the mutation in mammals may imply this virus has a propensity to cause zoonotic infections”, meaning it could potentially spread to humans.

Professor Brown said it was “difficult to control the disease in wild birds” but “what we can do is effectively control the disease in poultry”.

He added that, in the UK, the virus had not spread from one poultry farm to another.

“So if you can cut that source of infection off, and we can do that around the world, you reduce the risk of it spilling over into wild birds and evolving further.”

In its December analysis, the UKHSA said four samples from the affected otters and foxes “show the presence of a mutation which is associated with potential advantages for mammalian infection”.

It put the level of risk to human health at level 3, which means there is “evidence of viral genomic changes that provide an advantage for mammalian infection”.

There has been just once case of a human catching bird flu, a man in Devon in January 2022.