Dead sea lions were washed ashore in the Paracas National Reserve, in Peru, after dying of the virusCredit: AFP

Two dolphins were found dead off the UK coast after contracting bird fluCredit: Alamy

A highly contagious strain of avian influenza H5N1, commonly known as bird flu, was confirmed in the mammals by the Animal and Plant Health Agency.

The virus has wiped out millions of birds worldwide over the last two years, but it also affects other animals.

Although it is the first time dolphins have been killed by the infection in British waters, 23 other mammals have been affected.

It has spread to seals, otters, harbour porpoises and foxes – raising fears in recent months due to the “unprecedented” current outbreak since October last year.

The H5N1 strain already has a fatality rate of around 50 per cent among people – 870 people have been infected with bird flu in the past 20 years and 457 of these died.

A spokesperson for the Animal and Plant Health Agency said: “Samples taken as part of routine wildlife surveillance have detected the presence of influenza of avian origin in two dolphins and one porpoise.

“The animals were found dead, and it is very likely they had predated on infected wild birds.

“The presence of influenza of avian origin in mammals is not new, although it is uncommon, and the risk of the H5N1 strain to non-avian UK wildlife remains low.”

Elsewhere in the globe, bird flu has previously affected sea lions and mink as well as the winged animals.

This comes as scientists have warned the virus may be mutating to infect human cells after an 11-year-old girl died after contracting the stain.

The young girl in Cambodia is believed to have been infected by poultry in Prey Veng province, close to Vietnam.

She is the first person to die from the bug in 2023.

Her 49-year-old father – one of 12 close contacts tested – had also been infected.

Dr Erik Karlsson, who led the team at the Pasteur Institute of Cambodia that investigated the girl’s virus, said it differed from samples taken from birds in the area.

“There are some indications that this virus has gone through a human,” he revealed in an interview with Sky News.

“Any time these viruses get into a new host they’ll have certain changes that allow them to replicate a little bit better or potentially bind to the cells in our respiratory tract a little bit better,” he explained.

Scientists have called on the Government to create a vaccine for the flu before it can become more harmful to humans.

“If there was an outbreak in Europe, the Middle East, America or Mexico tomorrow of H5N1 in humans, we wouldn’t be able to vaccinate the world within 2023,” said Sir Jeremy Farrar, chief scientist of the Word Health Organization at a press briefing in London.

Health workers in protective suits cull ducks after the H5N8 bird flu strain was detected, in Karuvatta of AlapuzhaCredit: AFP

Scientists have called for a vaccine against the virus amid fears it will mutate to become more harmful to humansCredit: Getty