So what is being done to tackle the root cause of this devastating disease that is now spiralling out of control? Here, I look at what’s being done to stop this deadly avian disease and ask, could we see the emergence of another pandemic?
The UK has been hit by its largest-ever outbreak of avian influenza, also known as ‘bird flu’, with over 270 cases confirmed across the country since late October 2021. In that period, the disease globally has claimed the lives of an estimated 140 million poultry. This includes almost 48 million birds in Europe and the UK, and just over 53 million in the US, causing disruption to agriculture and the environment. The highly pathogenic strain of the disease is thought to have originated in intensive poultry and then spread into wild birds.
Now, public health officials say bird flu has been detected in four otters during routine testing. Monitoring is being stepped up to see if the virus that has devastated bird populations is taking a foothold in other mammalian species. As well as Scottish otters, newly published data by the UK Government’s Animal and Plant Health Agency (APHA), shows that five foxes in England and Wales have also been affected.
And the list of non-avian species affected continues to grow. Worldwide, the virus is reported to have been found in a range of mammals, including grizzly bears in America, as well as in dolphins and seals. Veterinary authorities in Peru have recently confirmed bird flu in sea lions. Against a backdrop of surging outbreaks in poultry in Central and South America, Peruvian authorities say that at least 585 sea lions and about 55,000 wild birds including pelicans and penguins have died, likely from avian influenza.
So, how worried should we be that deadly avian influenza is now directly spilling over into mammals? Professor Ian Brown, of the UK Government’s Animal and Plant Health Agency, told the BBC that he was "acutely aware of the risks" of bird flu becoming a pandemic like Covid. “If we don't solve the problem across the globe, we're going to continue to have that risk,” he added.
According to a UK Government briefing, published in December, there have been four instances of highly pathogenic strains of avian influenza in humans: one in the UK, one in the USA and two in Spain. All affected were involved in the poultry industry. UK Government advice continues to be that bird flu is primarily a disease of birds and the risk to the general public’s health is very low. But for how much longer?
Jumping the species barrier
A report in Nature suggests that an outbreak of avian influenza on a mink farm in Spain provides the “strongest evidence so far” that the highly pathogenic strain of bird flu can spread from one infected mammal to another. The outbreak in October 2022 involved a new variant of the disease, which included genetic material from a strain found in gulls.
According to Nature, this new variant’s genetic make-up also suggests an increased ability to reproduce in mammals. All of which puts bird flu into uncharted territory. “Researchers have warned that, unless careful precautions are taken, the disease might eventually spread among people,” the report said.
Mink farms in general are a source of particular concern. When these essentially wild animals are kept in cages, it causes immense stress and lowers their immune system, making them more vulnerable to disease. It’s a practice banned in Britain but still widespread in Europe.
As things stand, bird flu is not easily transmitted between people, but scientists have suggested that just a few mutations would allow it to become as infectious as seasonal flu. A recent editorial in the New Scientist described the risk of a pandemic as “fact, not fiction”.
More recently, bird flu was described by Professor Devi Sridhar, chair of global public health at the University of Edinburgh, as a ticking timebomb. “The more chances the virus has to jump into a human and mutate, the more likely it is a dangerous strain will emerge that could set off the next pandemic,” she warned.
Global poultry industry
The current high levels of bird flu infection in birds, both domesticated and wild, are without precedent. It is thought to have emerged originally in farmed birds during the massive expansion of the poultry industry in China and east Asia at the end of the 20th century. The low pathogenic version of the avian influenza virus is common in birds, both domesticated and wild.
As I explored previously, its evolution into a much more deadly form is likely to have been due to the huge numbers of birds kept at close quarters in the global poultry industry. This provides the perfect breeding ground for disease, giving viruses like avian influenza the conditions needed for new and potentially more deadly strains to emerge.
Yet so much of the coverage on bird flu fails to explore this link with industrial poultry production, something akin to writing about climate change without mentioning the fossil fuel industry. As bird flu continues to hurtle out of control, it can only be a matter of time before authorities have to address the underlying risk to our health and the wildlife around us posed by intensive chicken rearing.
Philip Lymbery is chief executive of Compassion in World Farming, a former United Nations Food Systems Champion, and author of Farmageddon: The True Cost of Cheap Meat; Dead Zone: Where the Wild Things Were; and Sixty Harvests Left: How to Reach a Nature-Friendly Future. He is on Twitter @philip_ciwf