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Bird flu risks: The “versatile” virus continues to spread – National | Globalnews.ca

As the deadly H5N1 bird flu continues to spread worldwide, wiping out colonies of sea lions, decimating bird populations by the millions and getting even worse For the first time in AntarcticaConcerns remain about the potential risks to human health.

The latest development came after the US Centers for Disease Control and Prevention (CDC) on Monday reported a human case of bird flu in a person who had contact with dairy cows in Texas that were suspected to be infected with the virus .

“So this highly pathogenic bird flu has been circulating at a very high rate around the world for several years,” explained Matthew Miller Director of the Degroote Institute for Infectious Disease Research at McMaster University.

However, the fact that dairy cows have never been involved before is a major concern, he said.

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Click here to play the video: “Bird flu virus spreads to mammals”


The bird flu virus spreads to mammals


“What makes the risk to humans worrying is the fact that we know that humans are most at risk of viruses entering them when they are in close proximity to infected animals. And in fact, this case in Texas appears to be traced to a cattle farm worker being near an infected cow,” he told Global News.

“It is a relatively new development that changes risk assessment.”

Although human cases remain rare, health experts warn there is an increased risk that bird flu will evolve to more easily infect people.

Avian influenza, also known as bird flu, is a disease caused by influenza viruses that spreads among wild waterfowl and can infect domestic poultry and other animal species. The viruses are different from those that cause flu in humans, but are related.

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The Avian influenza virus H5N1 first appeared in southern China in 1996 and has been causing bird plagues worldwide ever since.

Since 2020, a variant of these viruses from the H5 clade 2.3.4.4b has caused an unprecedented number of deaths in wild birds and poultry in many countries in Africa, Asia and Europe. In 2021, the virus spread to the United States and Canada and in 2022 to Central and South America. according to the World Health Organization (WHO).

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Globally, H5N1 has infected many mammals, including foxes, pumas, skunks and, in North America, both black and brown bears. Bird flu has already taken hold new corners of the world in recent years and is now present in Penguins that live in Antarctica And Polar bears in Alaska.

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The virus usually infects the gastrointestinal tract of birds and is excreted in the bird’s defecation, Miller said.

“For example, when ducks and geese move across grazing pastures and these birds defecate, this can contaminate the soil and drinking water, and this can lead to other animals becoming infected.” Of course, in many cases these infected birds can also die . And if scavengers eat these birds, that’s another way they can become infected,” he explained.

What danger is there for humans?

Human cases of H5N1 are primarily due to zoonotic transmission through direct contact with infected birds (dead or alive) or contaminated environments. Person-to-person transmission is extremely rare, Health Canada stated on its website.

The most recent death occurred in Vietnam last month. reported the WHO. A 21-year-old died on March 23 after testing positive for H5N1. The man had no history of contact with dead or sick poultry or people with similar symptoms. However, health officials said he had reportedly caught wild birds in his hometown.

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“In Canada, the risk to the general public is still very low,” Miller said.

However, he believes the cases of infected dairy milk require “increased attention,” particularly among people who are in close professional contact with wild and farm animals.


Click here to play the video: “Tackling Zoonotic Diseases in Ontario”


Combating Zoonotic Diseases in Ontario


“Historically, the real problem with highly pathogenic avian influenza infections in humans is that, despite relatively low transmission rates, they can cause much more severe disease than a typical influenza infection,” he warned.

“In previous bird flu outbreaks, mortality rates have exceeded 30 percent in some cases, which is extraordinarily high by other virus standards.”

Another special feature of this virus is that, unlike most seasonal influenza strains, which mainly affect the human lungs, the highly pathogenic bird flu can infect various organ systems in our body. In some cases, it can even reach the brain and cause serious complications, such as: Encephalitiswhich poses significant challenges to treatment.

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Should we worry about milk?

On March 25, US federal authorities announced the detection of bird flu in laboratory samples from some affected cows in Texas and Kansas. Days later, federal officials said that was the case confirmed the presence of the virus in a herd in Michigan and suspected additional cases in cows in New Mexico and Idaho.

Officials said they believed the cows contracted the virus from wild birds, but transmission among cattle “cannot be ruled out.”

It is the first time that the disease has been detected in dairy cows American Veterinary Medical Association (AVMA).

Shayan Sharif, professor and associate dean of the Ontario Veterinary College at the University of Guelph, called this transfer “quite surprising” and “quite unexpected.”

“But this virus has proven to be quite versatile. It can do many different things. And maybe we shouldn’t have been surprised if this virus had jumped from birds to cattle,” he said.

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Click here to play the video: “Avian flu discovered in dead skunks”


Bird flu discovered in dead skunks


Sharif previously said many infectious disease specialists were under the impression that the H5N1 virus could not be transmitted to cattle, but “many of our theories and hypotheses have been proven wrong.” That’s why I’m very worried about what this virus is can do in the future.”

Miller also believes Canadian farmers are exercising increased vigilance over their cattle in light of these cases. As spring begins, waterfowl migration will return to these areas, increasing the risk.

However, Miller assured that there is no risk of contracting the virus from pasteurized milk.

“This is why we pasteurize to kill any kind of germs that might be present in the milk. And that’s why pasteurization is so widespread and so important for preventing infections,” he said. “And in general there is no risk of contamination of meat products. So I don’t think people need to worry about that.”

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How to prevent future outbreaks

Miller and Sharif emphasize that the most effective strategy for preventing widespread bird flu outbreaks is to minimize the likelihood of transmission from animals to humans.

As Miller explained, the longer the virus has the opportunity to jump from animals to humans, the more likely it is to develop the ability to infect humans.

“Then it has the possibility of transmitting between people. This poses a risk of large-scale outbreaks or pandemics. And fortunately, as far as we know, this virus doesn’t do that efficiently, and we want it to stay that way.”

Sharif pointed out that many of the practices adopted during the pandemic can also be applied here, as bird flu follows a similar path to COVID-19. This includes minimizing contact with infected animals, ensuring thorough hand washing and disinfecting whenever possible.

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Another strategy to prevent an outbreak was vaccination.

“Currently in Canada we do not have a vaccination plan for poultry or cattle,” Sharif said. “But time will tell whether there will be a safe and effective vaccine for poultry and cattle.”

– with files from Katherine Ward and Reuters from Global News

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