With poultry stocks devastated, is there a whiff of the next pandemic in the air?

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While COVID-19 has dominated the headlines for the past three years, there is another pandemic unfolding that has claimed at least 150 million lives so far.

Avian influenza H5N1 has decimated populations of wild and domestic birds in the U.S., Canada, and Europe and appears to be picking up steam.

Should we care about a lot of dead birds?

For one, the mass culling of infected poultry – chickens, turkeys, ducks – has led to higher prices for eggs and meat. More importantly, the more widely H5N1 circulates, the greater the risk it could jump over the species barrier to other mammals, including humans.

Recently, there have been worrisome developments, like an outbreak of H5N1 at a mink farm in Galicia, Spain, late last year. Not only did mink get infected with avian influenza – perhaps from a wild bird, or from their food supply, which contains raw poultry – but H5N1 spread rapidly among the animals. More than 52,000 minks were euthanized.

The outbreak matters because it suggests the virus may have mutated to spread more readily in mammals. (Note the cautious language.)

Influenza is common in the animal world. But avian influenza is not usually a threat to humans because we don’t tend to interact closely with wild birds or domestic poultry. Even those who do – like poultry-farm workers – are rarely infected and, when they are, the virus settles deep in their lungs, and is not easily transmitted to others.

What we saw in the Spanish minks, however, was H5N1 in the upper respiratory tract. This is concerning because the respiratory tract of minks is remarkably similar to that of humans.

H5N1 avian influenza was first identified in a goose in Guangdong, China, in 1996, and has popped up sporadically since then in causing outbreaks, notably in 2003. The current outbreak has been growing steadily in Europe since 2021, and hit Canada and the U.S. hard in 2022. (H5N1 was likely carried by migratory birds who, in turn, mingled with farmed poultry.)

In the past year, at least 60 million domestic birds have been culled in the U.S., and millions more wild birds have died. (H5N1 is devastating – it has a 90 to 100 per cent mortality rate in infected birds.)

Canada has recorded more than seven million cases of what the Canadian Food Inspection Agency calls HPAI (Highly Pathogenic Avian Influenza, or H5N1).

Last year, duck farms in Quebec were devastated. Currently, more than half of the H5N1 outbreaks in Canada are on poultry farms in B.C.’s Fraser Valley. It’s the most ruinous outbreak since 2004, when 19 million birds were culled in B.C. to stop an outbreak of H7N3 avian influenza.

The difference this time around is that H5N1 seems far more widespread in wild birds. As the spring migrations begin, so does the threat of new outbreaks. The number of dead birds in the wild will also be far more obvious.

Many wild animals prey on birds, or at least interact with them. As a result, we have seen all manner of mammals infected – dolphins, seals, bears, foxes, skunks, raccoons, and even tigers and leopards in zoos who were fed raw poultry.

In the past 20 years, there have been only 868 confirmed cases of H5N1 in humans – most of them poultry workers – but 457 of them died. That’s an eye-popping 53 per cent mortality rate. However, we don’t know how many people have been infected and not detected because they developed only mild symptoms.

Despite some dire warnings that H5N1 could be the next pandemic – one far more devastating than COVID – there is still no real cause for alarm.

But the way avian influenza is spreading wildly, and appears to be adapting to mammals, should remind us of the need to be vigilant.

To avoid future pandemics, of H5N1 or other pathogens, we need strong surveillance. The world also needs to be ready to act swiftly if there are hints of any human-to-human transmission.

If COVID-19 taught us anything, it’s the need for swift containment when a potential pandemic threat is detected. Closing the barn door after a virus has gained a foothold in humans doesn’t work.

Whether we will have the foresight and gumption to act – especially given the COVID-19 backlash – remains to be seen. Canada, for one, has dismantled its pandemic warning system and needs to rebuild it.

H5N1 serves as a warning that pandemic preparedness is not just for the birds.