A human case of highly pathogenic bird flu has been detected in England, authorities have said, as bird flu cases escalate across the country.
It is only the second symptomatic human case of H5N1 bird flu recorded in the UK, after the first was detected in 2022, the UK Health Security Agency (UKHSA) said.
The individual contracted the infection on a farm in the West Midlands after contact with a large number of infected birds, with authorities describing it as a “very rare event”.
Prof Susan Hopkins, chief medical adviser at the UKHSA, said: “The risk of avian flu to the general public remains very low, despite this confirmed case.”
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What is bird flu?
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What is H5N1, the deadly strain of bird flu sweeping the world?
The current outbreak of bird flu started in Europe in 2021. By September 2022, H5N1 had been recorded in 63 wild bird species across 37 countries, according to an avian influenza overview published by the European Food Safety Authority. It hits seabirds particularly hard because they sit so close together during the breeding season: some colonies experience losses of 50% to 60%.
Then it crossed the Atlantic, with the first US case recorded in an American wigeon duck found in South Carolina in January 2022. By November it had reached South America. More than 40% of all Peruvian pelicans died over a period of a few weeks in early 2023.
Working out how many wild birds have died is difficult because so many carcasses are never found or counted. Researchers say it may be in the millions.
Does it affect other species?
The H5N1 virus has multiple genes that can switch and evolve together to spread the virus quickly into a wide range of species. The death of an estimated 20,000 sea lions in Chile and Peru shows that this is a disease that also kills mammals en masse. Black bears, brown bears and polar bears have also been killed.
How did it reach the Antarctic, and what will happen next?
The spread of this disease is facilitated by the migration routes of wild birds. It took just three months to spread almost 4,000 miles down South America, and it was seen as inevitable it would at some point reach the Antarctic.
It was first reported in the region in October 2023 among brown skua on Bird Island, off South Georgia. Since then it has spread into elephant seals, fur seals and kelp gulls. Most recently, it has been recorded in Antarctic penguin populations too.
So far there are no recorded cases on the Antarctic mainland, although researchers expect that to happen in the coming months. This latest H5N1 virus is yet to be reported in Oceania.
Since 2021 there have been seven cases of bird flu in humans in England, all of whom had been in direct contact with infected birds. Two developed symptoms, while the rest were asymptomatic.
The individual was admitted to a high consequence infectious disease unit and is currently well. The case was detected after routine monitoring of people who had been in contact with infected birds.
There has been no evidence of human-to-human transmission of bird flu and health authorities are testing all of the people who have been in contact with the infected person.
Hopkins said: “We have robust systems in place to detect cases early and take necessary action, as we know that spillover infections from birds to humans may occur.”
Human bird flu infections are alarming health officials. Since the beginning last year, the US has recorded 67 confirmed human cases of bird flu, most of which were found in people working in poultry or dairy farms. Most were considered mild, with low risk to the general public. However, the US announced its first death from the virus, in Louisiana, this month. Since last September there have also been 10 cases reported in China and one in Vietnam.
Bird flu can pass from birds to people but it usually requires close contact, which is why the risk to humans is generally considered low. There have been no documented cases of human-to-human transmission of bird flu in Britain or elsewhere in Europe.
Christine Middlemiss, UK chief veterinary officer, said: “While avian influenza is highly contagious in birds, this is a very rare event and is very specific to the circumstances on this premises.
“We took swift action to limit the spread of the disease at the site in question, all infected birds are being humanely culled, and cleansing and disinfection of the premises will be undertaken all to strict biosecure standards.”
The case comes three days after all of England and Scotland was declared a bird flu-prevention zone, with strict hygiene orders in place for fowls. The government said escalating number of cases of avian influenza and continued heightened risk levels in wild birds were behind its decision. Some eastern counties in England are under stricter measures and all birds will need to be placed in enclosures.
“We are seeing a growing number of avian flu cases in birds on both commercial farms and in backyard flocks across the country,” said Middlemiss. “Implementing scrupulous biosecurity measures will help protect the health and welfare of your birds from the threat of avian influenza and other diseases.”
The government advises people not to touch sick or dead birds, and report any suspicious avian influenza cases. Andrew Gwynne, minister for public health and prevention, said: “The safety of the public is paramount and we are monitoring this situation closely.
“We recently added the H5 vaccine, which protects against avian influenza, to our stockpile as part of our preparedness plans,” he said.
