Fears of a potentially devastating bird flu pandemic were heightened today after a “worrying” outbreak in mink.
Top virologists from around the world have sounded the alarm after tests confirmed the H5N1 strain is spreading between mammals.
It raises the prospect that the pathogen could take on problematic mutations that allow it to spread between humans much more easily, helping it clear the biggest hurdle that has prevented it from taking over the world.
A virus-tracking scientist described the H5N1 strain detected in Spain as similar to a strain deliberately engineered to better infect humans in controversial “gain of function” lab experiments.
Top virologists from around the world have sounded the alarm after tests confirmed the H5N1 strain was spreading between mink (pictured). The outbreak happened in October at a farm in Galicia, northwest Spain, that housed 52,000 of the animals
Alan Gosling (pictured), a retired engineer in Devon, contracted the virus after his ducks, some of whom lived at his home, became infected. No one else has contracted the virus
Avian flu outbreak: everything you need to know
What is it?
Avian flu is a contagious type of influenza that spreads among birds.
In rare cases, it can be transmitted to humans through close contact with a dead or live infected bird.
This includes touching infected birds, their droppings or litter. Humans can also contract bird flu by killing or cooking infected poultry.
Wild birds are carriers, particularly through migration.
As they band together to reproduce, the virus spreads quickly and is then carried to other parts of the world.
New strains typically first appear in Asia, from where more than 60 species of shorebirds, waders, and waterbirds make their way to Alaska to breed and mix with migratory birds from the United States. Others go west and infect European species.
Which strain is spreading now?
H5N1.
So far, the new virus has been detected in around 80 million birds and poultry worldwide since September 2021 – twice as many as in the previous year.
Not only is the virus spreading at a rapid rate, it is also killing at an unprecedented rate, leading some experts to say it is the deadliest variant yet.
Millions of chickens and turkeys in the UK have been culled or banned, affecting the availability of Christmas turkeys and free range eggs.
Can it infect people?
Yes, but since 2003 only 860 human cases have been reported to the World Health Organization.
The risk for humans was classified as “low”.
But people are being urged not to touch sick or dead birds because the virus is deadly, killing 56 percent of the people it infects.
Professor Rupert Beale, an expert in immunology at the world-renowned Francis Crick Institute in London, said: “We should already have vaccine contingency plans in place.”
And Professor Isabella Eckerle, a virologist at the University of Geneva’s Center for Emerging Viral Diseases, called the results “really worrying”.
Other experts warned that outbreaks among mink could lead to a recombination event – when two viruses exchange genetic material to create a new hybrid.
A similar process is believed to have caused the 2009 global swine flu crisis, which infected millions around the world.
The same biological phenomenon has also been observed during the Covid pandemic, such as the so-called deltacron – a recombination of delta and omicron first discovered in France last February.
For decades, scientists have warned that bird flu is the most likely contender to start the next pandemic.
Experts say this is due to the risk of recombination – with high levels of human flu strains increasing the risk of a human also becoming infected with bird flu.
This could result in a deadly strain of bird flu merging with transmissible seasonal flu.
The mink outbreak happened in October at a farm in Galicia, northwest Spain, that housed 52,000 of the animals.
It was only discovered after a sudden spike in animal deaths. Up to four percent died in a week during the outbreak, which was declared over in mid-November.
Farm vets wiped the mink and the samples were analyzed at a government laboratory, where they tested positive for H5N1.
This resulted in all animals being culled, farm workers being isolated for 10 days and security measures being tightened on farms across the country.
This included wearing face masks and disposable overalls, and showering before leaving the premises.
Analysis of collected samples, published yesterday in the infectious disease journal Eurosurveillance, shows that the virus had acquired nearly a dozen mutations – most of which had never or rarely been seen before in avian flu strains.
One was previously seen with the virus behind the 2009 global swine flu pandemic.
Scientists examining the samples believe it was triggered by an H5N1 outbreak among seabirds in a nearby province.
The UK had a record number of bird flu cases last winter. Levels typically fall in spring and summer, but the breakout rumbled past its usual endpoint. Since the current outbreak began in October 2021, nearly 300 confirmed H5N1 cases have been detected in birds in England. However, the true number is estimated to be much higher
The report, by experts from Spain’s Ministry of Agriculture, Fisheries and Food and some experts from the Council of Rural Affairs, says H5N1 has spread among mink in Europe for the first time.
They warned that mink could act as a “potential mixing vessel” for H5N1 transmission between birds, mammals and humans – such as by recombination of the strain with human flu viruses that can infect humans.
Increased biosecurity measures on mink farms and increased surveillance are needed to limit the risk of transmission to humans, the report warned.
Professor Francois Balloux, an infectious disease expert at University College London, said: “The sequenced genomes carry several rare or previously unreported mutations that were likely acquired after transmission from mink to mink.
“AH5N1 avian influenza can infect a range of carnivores and sometimes humans. Small clusters have been reported in humans, but human-to-human transmission is ineffective.
“Such outbreaks of avian influenza in mink farms are highly suboptimal as they result in natural ‘passage experimentation’ in a mammalian host which could result in the virus evolving higher mammalian transmissibility.”
dr Jeremy Ratcliff, a senior scientist at Johns Hopkins University’s Applied Physics Laboratory in Maryland, said there was no reason to panic about the outbreak because it ended two months ago.
“However, that H5N1 can successfully adapt to mammalian transmission is of general concern,” he added.
Other online virologists warned that the mutant version of H5N1 was similar to one made in a lab to better infect mammals.
They pointed to a controversial experiment by Dutch scientist Ron Fouchier in which H5N1 was modified to make it better able to infect ferrets.
The findings sparked controversy among the scientific community and security agencies over concerns they could be used to create a bioweapon.
The results showed that a version that could infect mammals could be achieved with just a few modifications to the virus.
The US National Science Advisory Board for Biosecurity requested that some parts of the results not be published – but eventually allowed the results to be published in the journals Nature and Science.
Proponents of these so-called “gain of function” tests claim they can aid in pandemic preparedness by revealing how viruses can mutate and allowing scientists to develop drugs and vaccines that work against them.
But critics argue the experiments could trigger an outbreak if the virus accidentally escapes from a lab, which is how some scientists believe the Covid pandemic began.
The UK had a record number of bird flu cases last winter. Levels typically fall in spring and summer, but the breakout rumbled past its usual endpoint.
Since the current outbreak began in October 2021, nearly 300 confirmed H5N1 cases have been detected in birds in England. However, the true number is estimated to be much higher.
A year ago, the first case of H5N1 in a person was recorded in the UK.
Alan Gosling, a retired engineer in Devon, contracted the virus after his ducks, some of whom lived at his home, became infected. No one else has contracted the virus.
The virus has trouble attaching to human cells, unlike seasonal flu, scientists say. As a result, it is usually unable to enter them and cause infection.