Over the past few months, Canadians have heard about the spread of the H5N1 avian flu, which is wreaking havoc on poultry farms across the country.
It is a virus that has also gained a foothold in the world. The World Health Organization says that although H5N1 has “widely spread in wild birds and poultry over the past 25 years”, there are now several international reports of contagious infections in mammals including mink, otters , foxes and sea lions.
It has raised concerns that humans could be next and the WHO is urging countries to “strengthen surveillance in environments where humans and farmed or wild animals interact”.
“At this time, the WHO assesses the risk to humans as low,” Dr. Tedros Adhanom Ghebreyesus, the organization’s director-general, said at a news conference Feb. 8.
“Since H5N1 first emerged in 1996, we have seen only rare and unsustained transmission of H5N1 to and between humans, but we cannot assume this will remain the case and we must be careful. prepare for any change in the status quo.”
Dr Syra Madad, an infectious disease epidemiologist at the Harvard Kennedy Belfer Center for Science and International Affairs in Cambridge, Mass, agrees.
“I don’t think it’s necessary to cause significant alarm, but it’s time to be careful,” Madad said.
“When you talk about a highly pathogenic bird flu virus…that’s something to be taken seriously,” she said.
“It’s something where we have to make sure we prepare for the potential of human cases.”
What is H5N1?
H5N1 is a large family of influenza A viruses, said Dr. Shayan Sharif, acting dean of the Ontario Veterinary College at the University of Guelph.
Some are highly pathogenic and others have low pathogenicity, i.e. the ability to kill or seriously sicken birds.
Concern is currently focused on the highly pathogenic H5N1 circulating around the world.
It is called “bird flu” or “bird flu” because it has mainly infected birds.
Why do we hear about H5N1 now?
“Unfortunately, it looks like the virus is gaining a bit more momentum in terms of what it has done so far and what we anticipate it could do in a short period of time,” Sharif said. .
“Over the last few months or so, it’s been happening all over the world,” he said. “He has criss-crossed our country on several occasions.”
He is concerned both by the multiple cases of mammalian infections around the world and the implications this has for the spread of the virus to humans.
“When mammals die from a highly pathogenic bird flu virus, it’s not a good sign. This is a sign that I would take very seriously, extremely seriously.
In Canada, there have been “sporadic” transmissions to non-avian animals, including mammals, Sharif said, but there have been no signs of mammal-to-mammal transmission in this country.
Has H5N1 spread to humans?
Yes, but human cases are “quite rare” and have occurred when people have been directly exposed to infected animals, according to the WHO.
Worldwide, humans have rarely transmitted the virus to another human “unless they have a very, very close contact or a very specific transmission condition”, said Dr Sylvie Briand, director of the WHO for the preparation and prevention of epidemics and pandemics, during the conference on February 8. briefing.
In Canada, a “travel-related” human case was reported in early 2014, the Public Health Agency of Canada announced in an email Friday.
“This was the first and only case of H5N1 reported in Canada to date,” the email said.
How sick do humans get with H5N1?
H5N1 is “low transmissible” between humans because it is a “zoonotic virus and therefore the virus is very adapted to animals and not to humans”, Briand said.
But when humans have been infected, “they are more likely to have severe disease,” she said, and people have died 30-50% of the time.
There were a total of about 860 human cases of H5N1 reported worldwide between 2003 and 2021, Madad said.
While the death rate sounds frightening, she cautions that “we just don’t know” if that rate is accurate, as most cases were likely identified when the patient was sick enough to be hospitalized. That means many non-fatal cases could have been missed because they were never tested, Madad said, and there may have been asymptomatic people.
What are the symptoms for humans?
“People infected with avian influenza (H5N1) can become seriously ill quickly,” says an information page on the Public Health Agency of Canada’s website.
Symptoms begin like other flu-like illnesses and can include high fever, cough, muscle aches and sore throat. Other possible symptoms include stomach pain, chest pain, and diarrhea.
“The infection can rapidly progress to: severe respiratory illness, which may include difficulty breathing; pneumonia; Acute respiratory distress syndrome; (and/or) neurological changes (altered mental state or seizures),” the webpage reads.
How can people protect themselves?
Those at risk right now are those who have close contact with birds, Madad said, whether they work on a commercial farm, raise chickens in their backyard or interact with wild birds.
“It’s important that they understand there’s obviously a very large outbreak going on,” she said. “If they come across a sick bird, they have to be very careful.”
The Public Health Agency of Canada recommends people wear personal protective equipment, including a mask, gloves, goggles and boots.
They should also avoid touching their mouth, nose or eyes before washing their hands thoroughly, Madad said.
People should consider taking these precautions whenever they handle birds, even if none of them appear sick, she suggested.
As for birds in the wild, “members of the public should not handle sick or dead wild birds or other wild animals,” the Public Health Agency of Canada’s website says.
“Pets should also be kept away from sick or dead wild animals.”
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Canadian Press health coverage is supported through a partnership with the Canadian Medical Association. CP is solely responsible for this content.
Nicole Ireland, The Canadian Press
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