Scientists warn risk of human bird flu pandemic is rising
Bird flu infections across the globe have raised alarm bells for scientists
After England reported its first case of bird flu this week, concerns were raised about the possibility of an avian flu pandemic.
Although there is currently no evidence the virus can be transmitted from person to person, experts fear the virus has completed its first “stepping stone” towards humans.
The virus has even adapted to new hosts around the world, such as cows and seals, sparking a global crisis and raising the risk of spread amongst humans.
The Doomsday Clock inched closer to midnight yesterday (January 28) as the risk of human destruction is closer than ever before. Concerningly, experts cited the highly contagious avian flu as one of the reasons behind the move.
The Bulletin of the Atomic Scientists (BAS) said: “The off-season appearance and in-season continuance of highly pathogenic avian influenza (HPAI), the number and types of birds it has infected, the number and types of mammals to which it has spread, its appearance in dairy products, and the troubling occurrence of human cases have combined to create an increasingly worrisome situation.
“The ability of all influenza viruses to mutate, break apart, and recombine to create new strains makes the emergence of a human-transmissible version of bird flu a serious possibility.”
The United Nations (UN) health agency reported last month that avian flu had hit 108 countries across five continents, causing the deaths of more than 300 million birds worldwide.
Now, a large number of outbreaks have been reported in the UK, with one confirmed human case. Should we be worried about a bird flu pandemic?
The global bird flu crisis
Bird flu, also known as avian flu, is a form of the influenza virus that is highly contagious amongst birds and, in rare cases, can spread to humans.
Most strains of avian flu don’t affect humans, but the H5N1 strain – which was first detected in humans in 1997 – has led to human infections and resulted in a number of deaths worldwide.
The US Centers for Disease Control (CDC) says bird flu is “widespread in wild birds worldwide,” with 67 confirmed US human cases and one bird flu related death since the 2024 outbreak.
Scientists understand that pandemic can occur when a virus adapts to spread between humans. There is no evidence to suggest that bird flu can be passed from person to person, as all human cases have been traced back to contact with ill birds.
That said, the virus is adapting to new hosts. Bird flu has infected mammals as well as birds in some parts of the world, with seals and sea-lions affected in South America and dairy cattle affected in the US.
“If the virus has adapted to cows, it is also better adapted to go into human cells,” Daniel Goldhill, an evolutionary virologist at the Royal Veterinary College told Nature. “This is a first stepping stone for the virus — and it has increased the risk level of a virus jumping to humans.”
Goldhill co-authored a study which found that bird flu virus is becoming better at spreading between cows. Although the study has been published on a preprint server and has not yet been peer reviewed, the findings suggest the virus has “a tonne more opportunities” to adapt to humans because it has infected so many cows across the US, Goldhill says.
The situation in England
A rare human case of avian flu was confirmed in England this week (January 27) by the the UK Health Security Agency (UKHSA), which said the person in the West Midlands was infected after “close and prolonged contact with a large number of infected birds” on a farm.
Strict restrictions were placed on the whole of England and Scotland earlier this week to try to slow the spread of bird flu.
According to Professor Ed Hutchinson, Senior Lecturer at MRC-University of Glasgow Centre for Virus Research (MRC CVR), “this is the UK experience of a global outbreak of H5N1 in wild birds, and its effects are different in other parts of the world.”
Prof Hutchinson says the difference in the outbreaks may be due to the strains having different properties. “In the USA and Canada there have been two recent cases of humans getting severely ill after catching H5N1 from birds, in one case sadly leading to the person’s death,” explains Hutchinson.
“This underscores the potential risks of H5N1 infections, but it is also worth nothing that the H5N1 viruses currently circulating in UK birds are from a different strain of the virus to the ones in North America.”
Despite the confirmed case of the H5N1 strain of the virus, Prof Hutchinson says the risk of bird flu to the general public remains “very low”. As it stands, the current UK strain cannot be passed from person to person, but researchers are seeking to understand how the virus could evolve in the coming months.