By Dr. Shayan Sharif, interim vice president research and innovation, and Dr. Evan Fraser, director of the Arrell Food Institute
This article is republished from the Toronto Star. Read the original Opinion commentary
All around us, a crisis is brewing. We are not referring to how the guard rails on democracy are being dismantled south of the border, but rather a less obvious crisis that may turn out to be even more significant. This is the real threat that bird flu could be the next human pandemic.
Since 2021, almost 150 million poultry in the U.S. and over 14 million in Canada have been culled, causing U.S. egg prices to skyrocket. The reason, producers have been hit by bird flu or highly pathogenic avian influenza (aka H5N1).
This influenza strain has been around for decades and flares up occasionally. For consumers already reeling from 18 months of rising food costs — and for the food banks and other forms of emergency food delivery — this is exacerbating food insecurity. But there are worrying signs that this crisis is about to grow scary indeed.
The problem is that H5N1 has evolved to infect not just poultry but dozens of other species. Epidemics among wildlife, some of which are endangered species, has proven catastrophic.
Concerns about avian flu transmission between people
For example, colonies of elephant seals in Argentina lost close to 96 per cent of their pups due to H5N1. To make matters worse, in early 2024, H5N1 started spreading through U.S. dairy herds. And while thankfully only a small number of humans have been infected, if the virus changes again, it could gain the ability to infect people more readily and, potentially, be passed from person to person.
Given we do not (yet) have transmission between people, it is hard to estimate the human cost of such a mutation, but early evidence suggests that an H5N1 pandemic could be much worse than COVID.
To figure out how to prevent a bird-flu pandemic in humans, we need to better understand the story of this virus. H5N1 is part of the flu family and resides in migratory birds that mingle each year before dispersing across the continent in the spring and fall.
Infected birds carry H5N1 and although some carry the virus without signs, for other species, the disease can kill infected individuals within days. Whenever migratory birds, especially waterfowl like ducks and geese, interact with domesticated poultry flocks, there is a very real possibility of even greater spread. And with each outbreak, the opportunity for the virus to mutate into something more dangerous to humans grows.
One Health approach that considers human, animal and environmental health
One approach is to manage this problem using laboratory testing to identify outbreaks in flocks and cull all the birds (healthy or not) that may have been in contact with the infection. Although this has proven effective in the past, it is extremely costly and difficult to execute.
Importantly, it is now clear that this approach is not working well with the current strain of avian flu, which is mostly spread by wild birds. Scientists, therefore, advocate for taking a “one health” approach that considers human, animal and environmental health as all part of one seamless system.
We have had major successes using one health to fight off major infectious diseases. Rabies in the 20th century went from a major problem to being almost eliminated once we realized that a combination of surveillance, vaccination and managing both domestic and wild animals can protect people from disease.
Managing avian flu is a bigger than controlling rabies. The spread of H5N1 since 2021 is unprecedented and unlike anything we have witnessed in the last century. To make matters worse, the virus is still criss-crossing our country and at the same time, rapidly changing itself. The big question is whether it can gain the ability to transmit to humans and then jump from humans to humans.
For decades, we have seen massive underinvestment in animal and one health research and this has left both our food systems and public health vulnerable to diseases such as COVID and avian influenza. Canada should be a global leader in pandemic response and can achieve this by taking a one health approach. This means we must establish the resources and infrastructures to predict, detect and mitigate potential pandemics that emerge from our changing environment.
The time to act was years ago; let’s hope we are not too late to prevent the next pandemic.