Millions of migrating birds pass through southwestern Ontario. Here's how researchers are tracking avian flu

CBC

06-05-2025

The researchers plan to continue sampling the region until at least the end of the year
Image | Birds at Holiday Beach Conservation Area
Caption: Geese are some of the wild birds that will pass through Holiday Beach Conservation Area, in Amherstburg, Ont. or make it their home. (Jennifer La Grassa/CBC)
At a conservation site in southwestern Ontario, research student Cam Chevalier lies down flat on his stomach on a wooden bridge and reaches over the edge to scoop some water into a bottle.
The sample he collects at Holiday Beach Conservation Area is the final one for the day — he's already been to nine other locations where migrating birds stop along the northern shore of Lake Erie. On top of the samples, Chevalier also makes note of the birds he sees out and about that day.
He then delivers a case full of the labelled samples to the University of Windsor, where researchers test it for highly pathogenic avian influenza (H5N1).
The disease, which is commonly known as bird flu, has been surging in the United States. Millions of birds have been impacted by the H5N1 strain, which has also crossed species and infected mammals like cows, cats and dogs. There's also been other strains circulating.
The start of spring migration in February means that millions of birds from the U.S. have been moving north into Canada.
"Essex County lies at the crux of two major migratory flyways," said Chevalier.
And that means that the region is, "a hotspot for understanding which species of birds move into our region, whether they carry the virus [and] whether they shed that virus into our waterways so that we can detect it," according to Dan Mennill, Chevalier's supervisor and University of Windsor ornithologist.
Many of the birds that stop over in Essex County after crossing Lake Erie will head to other parts of Canada, like northern Ontario, Quebec and Manitoba, says Mennill.
For Mennill, what's unique about this project is that it's one of few to look at how wild birds, like a Canada goose or a mallard duck, can spread avian influenza.
"We need to be ready for if avian influenza becomes a serious risk to human health," said Mennill.
"For us to be ready to handle that kind of situation, we need to know which birds are the primary vectors that transmit this virus, we need to know how it moves in wild birds [and] how it moves between wild birds and domestic birds."
What are the researchers tracking?
University of Windsor chemistry professor Kenneth Ng had actually pitched this project.
Ng and his team are not only checking for the virus in the water samples they receive, they're also closely tracking any changes to the virus' structure.
"What we are definitely concerned about, and what a lot of people are concerned about, are changes in the virus that allow it to infect people more easily and then to spread among people more easily," said Ng.
While there have been 70 people infected in the United States, there's only been one reported in Canada.
For now, there's been no reported spread of bird flu between people. But the strain of H5N1 circulating in cows in the U.S. is just one mutation away from being more transmissible between humans, suggests a study recently published in the peer-reviewed journal Science.
"The virus is constantly changing," said Ng.
"There are a lot of changes that happen that don't increase the ability of the virus to spread and then there are these rare changes that do."
What have they found so far?
What's hard, says Ng, is knowing which changes could be consequential.
"There are some changes that are known that would improve transmission, but I would have to say that there are many other changes that are not known," he said.
While they've been making note of any changes they find, Ng says the information they're gathering right now is creating a baseline for them to compare future samples to.
If bird flu becomes a bigger public health problem, where the disease is easily infecting people and spreading, Ng says that's where their data could play a role.
"The information that we have would help to define like the start of a pandemic more quickly than like if you didn't have that information," he said.
The researchers plan to continue sampling the region until at least the end of the year.