‘Big Leap’ in Bird Virus Threatens Another Pandemic

Ritzau Scanpix/Mads Claus Rasmussen via Reuters

Ritzau Scanpix/Mads Claus Rasmussen via Reuters

The same highly pathogenic bird flu virus that has killed thousands of chickens and other poultry over the past year has come much closer to infecting humans as well.

An unusual outbreak of the H5N1 virus in mink – relatives of the eels – at a Spanish fur farm this past fall also exposed farm staff to the virus. Quick action by health authorities helped prevent any human infections. This time.

But the bird flu is not going away. And as H5N1 continues to spread in domestic and wild birds, causing millions of animal deaths and straining the egg supply, it is also getting closer and closer to the human population. “This bird flu has the potential to be a big problem for people,” Adel Talaat, a professor of pathological sciences at the University of Wisconsin-Madison, told the Daily Beast.

It may be a matter of time before H5N1 achieves a large-scale “zoonosis” and makes the jump to the human species. If and when that happens, we could have yet another viral crisis. On top of the COVID pandemic, seasonal RSV is on the rise, with occasional smallpox flare-ups and annual flu outbreaks.

Reports this week suggested that the current wave of bird flu could be crossing into mammals more regularly. ​​​​Scientists found traces of bird flu in seals that died in a “mass mortality event” in the Caspian Sea in December, and the BBC reported this week that tests in Britain found the virus in a range of mammals All over the country. On January 9, the World Health Organization was informed that a 9-year-old girl in Ecuador had tested positive.

Bird flu is nothing new. Scientists first identified the virus back in the 1870s. There have been many large outbreaks over the years—and they have grown more frequent, and more severe, as the global poultry population has expanded to support a growing human population.

H5N1, a more severe “highly pathogenic avian influenza” – or HPAI – virus first appeared in China in the 1990s. It and other HPAIs have caused small-scale zoonoses, mostly in Asia. Several dozen people have died from bird flu in recent years.

But so far, bird flu has mostly infected, well, birds. So it is a huge problem for poultry farmers. And for people who buy eggs, of course. The current H5N1 outbreak has killed or forced farmers to cull nearly 60 million chickens, turkeys, geese and ducks in the United States alone. The slaughter increased the price of eggs to nearly $5 a dozen at US grocery stores last fall, according to the US Department of Agriculture. That’s several times the long-term average price.

Bird Flu Taking the Leap

Higher egg prices are the least of our problems if large-scale zoonoses start a human bird flu pandemic. And that’s why scientists and health officials keep a close eye on H5N1 and related HPAIs as they spread and mutate. For epidemiologists, the bird flu outbreak at the mink farm in northwestern Spain was a huge red flag. An ominous sign that severe zoonosis may be more likely.

Spanish health officials first noticed the outbreak in early October, when the death rate among mink on a large farm in Galicia tripled. Biological samples from the farm’s 52,000 mink contained H5N1. This was the first time that a farmed mink had been infected with bird flu in Europe.

The Authorities ordered the killing of all the minks on the affected farm. At the same time, they quarantined and tested 11 farm workers. Fortunately, no one caught the virus.

It was a close call. And it’s even more worrying because no one knows for sure what happened. “The source of the outbreak is still unknown,” a team led by virologist Montserrat Agüero reported in the latest issue of Eurosurveillance, a journal of epidemiology. Wild birds can spread the virus to the minks. It is also possible that the pathogen was present in the mink’s food, which contains raw chicken.

Also, the virus did not just spread from birds to mink. It could also be spread from mink to another mink, as well, Agüero’s team found. “This is suggested by the increase in the number of infected animals identified after confirmation of the disease.”

That post-zoonotic transmission within a new species is how an animal virus such as H5N1 could create a new pandemic. That’s what happened with COVID, after the SARS-CoV-2 virus spread from bats or pangolins to humans back in late 2019. That’s what happened with monkeys, after that pathogen jumped from monkeys and rodents to humans, maybe twenty or thirty years ago.

How China’s COVID Crisis Could ‘Leap’ Spawn a Devastating Virus

“The ability to achieve sustained transmission in a mammal is a big leap for influenza viruses, so the mink event is a big one,” James Lawler, an infectious disease expert at the University of Nebraska Medical Center, told The Daily Beast. “It certainly increases the risk for [a] species-jumping for humans.”

The bird flu outbreak in Spain has a happy ending for everyone involved—except those 52,000 minks, of course. But the next outbreak may not end so neatly. Not if scientists are late in noticing a zoonotic jump, or if viral transmission exceeds the ability of health officials to kill infected animals, quarantine exposed people and isolate the virus.

Avian flu requires constant surveillance than many viruses. It is infecting more birds than ever before, jumping to mammals in more places and learning new genetic tricks that increase the risk to humans.

That means the bird flu problem could get worse before it gets better. “Continuing widespread outbreaks of HPAI is a worldwide concern,” Lawler said.

Read more at The Daily Beast.

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