For the first time, two dolphins have died of bird flu in British waters, the government said.
The mammals were found in two different locations last month, on beaches in Devon and Pembrokeshire.
At least one of them has been confirmed to have the H5N1 strain, a highly contagious variant of bird flu that has killed millions of birds worldwide in the last 18 months.
Deaths were either directly from the virus or from culls, and the disease has also affected some mammals.
Other dolphins have previously been killed by bird flu around the world, but this is the first time this has happened in the UK.
Exactly 23 mammals have been affected in the UK so far, including a porpoise, seals, otters and foxes.
In other parts of the world, mink and sea lions are affected.
The virus is thought to be spread through animals eating dead infected birds, rather than directly to each other.
The government said there was no evidence of an increased risk to mammals after the dolphins died.
A spokesman for the Animal and Phytosanitary Agency said: “Two dolphins and one harbor porpoise were found to have influenza of avian origin in samples taken as part of routine wildlife surveillance.
“The animals were found dead and it is very likely that they had eaten infected wild birds.
“The presence of influenza of avian origin in mammals is not new, although uncommon, and the risk of the H5N1 strain to non-avian wildlife in the UK remains low.”
They said the results have been shared with the World Organization for Animal Health.
The risk of humans catching bird flu is considered very low and the only cases have occurred in humans who have been in close contact with infected birds.
It is not believed that people can pass it to each other.
However, World Health Organization Director-General Tedros Adhanom Ghebreyesus warned: “We cannot assume that this will continue and we must prepare for any change in the status quo.”
Anyone who comes into contact with wild animals is advised to wash their hands thoroughly afterwards and avoid touching a sick or dead wild bird.
Late last year it was announced that 600,000 turkeys had died or been culled from bird flu.
The ongoing epidemic has caused so many egg and meat supply problems that the US is now considering vaccinating chickens against bird flu.
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https://metro.co.uk/2023/03/17/bird-flu-kills-two-dolphins-found-dead-off-uk-coast-18458616/ Avian flu kills two dolphins found dead off UK coast