The increasing spread of bird flu among humans is a ‘huge concern’, the World Health Organization has warned.
The virus, a highly lethal H5N1 subtype, caused a devastating decline in bird populations after emerging in Europe in 2020.
Since then, the virus has jumped to mammals such as cows, cats, seals and now to humans, increasing the risk of the virus mutating and becoming more transmissible.
Although there is no evidence of human-to-human transmission, scientists have warned it would be significantly deadlier than Covid.
World Health Organization experts said the strain would face an “extremely high” mortality rate if it were to emerge, currently killing more than half of those infected. Jeremy Farrar (pictured), chief scientist at the UN health agency, said: ‘I think this remains a huge concern’
British scientists tasked with developing ‘early human transmission scenarios’ of bird flu have warned that 5 percent of infected people could die if the virus spreads to humans (shown under scenario three). In another scenario, the scientists assumed that 1 percent of those infected would be hospitalized and 0.25 percent would die – similar to how deadly Covid was in the fall of 2021 (scenario one). The other saw a mortality rate of 2.5 percent (scenario two)
According to the UKHSA, more than 700 confirmed cases of H5N1 have been detected in wild birds in England since September 2022. Pictured above: An outbreak of bird flu last February in Queens Park, Heywood, Rochdale
WHO experts say people would face an “extremely high” death rate if the disease were to persist, currently killing more than half of those infected.
Jeremy Farrar, chief scientist at the UN health agency, said: “I think this remains a huge concern.”
Describing it as ‘a global zoonotic animal pandemic’, the former SAGE adviser told reporters: ‘The big concern, of course, is that in infecting ducks and chickens and then increasingly mammals, that virus is now evolving and developing the ability to to infect people. and then crucially the ability to go from person to person.’
He added: ‘When you get into the mammal population you get closer to humans… this virus is just looking for new, new hosts.
“It’s a real concern.”
There is no evidence yet that the virus, responsible for the deaths of tens of millions of poultry and wild birds, is spreading among people.
But its evolution to infect more species is what worries scientists most.
In the hundreds of cases where people have become infected through contact with animals, “the mortality rate is extremely high,” Sir Jeremy said.
Official data shows that between 2003 and April 1, 2024, 463 deaths from 889 human cases were recorded in 23 countries. This brings the mortality rate to 52 percent.
U.S. authorities said earlier this month that a person in Texas was recovering from bird flu after being exposed to dairy cattle.
It was only the second case of a human testing positive for bird flu in the country and came after the virus sickened flocks apparently exposed to wild birds in Texas, Kansas and other states.
It also appears to have been the first human infection with the influenza A virus strain through contact with an infected mammal, the WHO said.
Sir Jeremy Farrar said more monitoring is needed to understand how human infections are happening, ‘because that’s where adaptation (of the virus) will take place’.
“It’s tragic to say, but if I get infected with H5N1 and die, that’s the end. If I go around the community and tell someone else, you start the cycle.”
A report from the Rare Breeds Survival Trust (RBST) warned this week that all native chicken, duck, geese and turkey breeds in Britain are threatened by bird flu.
Efforts are underway to develop vaccines and therapies for H5N1, should the situation escalate.
But Sir Jeremy stressed that regional and national health authorities worldwide need capacity to diagnose the virus to ensure the world is ‘able to respond immediately’.