Bird flu outbreak: Can humans contract the virus? Expert weighs in

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Zoo closing aviaries after bird flu detected in Southern Ontario
WATCH: Zoo closing aviaries after bird flu detected in Southern Ontario – Mar 29, 2022

As cases of bird flu continue to be detected in Ontario, and now in Quebec, one expert says containing the virus is critical to preventing a large-scale outbreak.

According to the Canadian Food Inspection Agency (CFIA), the H5N1 strain has been detected in a backyard flock in the Township of Chippewas of Nawash, and in poultry flocks in Woolwhich,  Zorra and Guelph.

On Monday, officials said the virus was also detected in wild birds in Quebec.

What is bird flu and can humans get sick? Here’s a closer look at what’s going on.

What does bird flu look like?

According to the CFIA, there are a number of “clinical signs” that can be found in infected birds.

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There will be a drop in the production of eggs, many of which are soft-shelled or shell-less. Birds may have diarrhea or haemorrhages on the leg, and may be quiet, showing signs of extreme depression.

Birds with the flu may also present with swelling under their eyes, and their wattles and combs may become swollen and congested.

According to the CFIA, there is no treatment for birds with the disease.

“Vaccinating the birds may play a role in reducing the spread of the disease but it does not eliminate the virus,” the CFIA website states.

Dr. Mary-Jane Ireland chief veterinary officer for the CFIA, told the Canadian Press that infected birds can shed the virus in their saliva, natal secretions and feces.

“And it can spread through contact with surfaces,” she said.

Ireland said that includes shoes, litter, bedding, feed and water.

She said anyone who has birds should keep them away from wild birds, and frequently clean the poultry coops, water, feeders and clothing.

They should also control what goes in and out of the coop or barn.

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Can humans contract the bird flu?

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Dr. Shayan Sharif is a professor and associate dean with the Ontario Veterinary College at the University of Guelph.

He told Global News the virus that has been detected in this outbreak is a member of a “very large family of influenza viruses.”

Sharif explained that while some of the influenza viruses are pathogenic — they can cause disease in humans — others can’t.

“This particular virus, or more scientifically speaking, this particular subtype of influenza virus, is a one that is usually found in avian species: in poultry, in migratory birds and so on.”

Sharif said is it “quite deadly” in some avian species, but less so in others.

“So poultry — and I’m talking about chickens and turkeys — they’re very susceptible to this particular strain of influenza virus,” he said, adding they can die within 48 hours of falling ill.

Sharif said currently, the virus is not pathogenic to humans, meaning it won’t cause people to become sick.

“But there is always the concern that this virus could gain capability to become pathogenic or disease-causing for humans,” he said. “Because avian influenza virus just like many other viruses, for example COVID-19, can mutate.”

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He said when the virus mutates, it can jump between species, including to humans.

“If you go back to early 2000s, up to probably the late 2000s, there were a few hundred cases of human infection, not exactly the same virus, but the virus that was also H5N1,” he explained. “Especially in southeast Asia, especially in North Africa, and also some parts of China, this became quite prevalent, and it caused significant amounts of mortality actually, in humans.”

Sharif said “thankfully” there is “no evidence” the present subtype has infected humans so far.

Can people become sick by eating poultry?

Sharif said it’s also “extremely, extremely unlikely” this bird flu could find it’s way to the human food system, meaning people won’t catch the virus from eating poultry.

“This particular strain of virus is quite susceptible to heat,” he explained. “So heating chicken meat and heating eggs could very easily obliterate the virus.”

In the past, Sharif said those who have contracted avian influenzas were people who were found to have had “close contact” with poultry.

“Especially in live markets in China and other places in southeast Asia,” he explained.

How big of an outbreak will this become?

Sharif said what isn’t clear right now, is how far this outbreak could spread. He noted that it has already been detected in “various regions of the province.”

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“I have a sense that probably we haven’t seen the end of this outbreak or the series of outbreaks, probably we’re going to see more of these popping up over the next little while,” he said.

Sharif said we are also looking at the “tip of the iceberg” when it comes to understanding how far it has spread among migratory birds.

He said while the virus can kill some migratory birds quickly, others are “actually resistant to the virus.”

This means they could act as a reservoir for the virus, carry it to other areas and shed it into new environments.

“That would be quite disconcerting because we have no way of knowing. We can’t sample all of the migratory birds in Ontario,” he said.

Ireland told the Canadian Press that the CFIA believes wild migratory aquatic birds are the major reservoir for the bird flu virus, and are responsible for bringing the disease into the area.

She said the virus can also be brought into farms from contaminated manure and contaminated litter.

What’s more, Sharif said the virus could mutate and jump species and infect dogs, cats or other farm animals.

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“Influenza viruses are actually quite good at adapting themselves to the new environments,” he said. “And they usually have very limited amount of species barrier. So they can actually jump quite freely from one animal host animal to another animal host.”

“That’s precisely why we are concerned about this subtype spreading in Ontario,” he said.

— with files from The Canadian Press

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