A British Columbia teenager has a suspected case of H5N1 bird flu – the first known human to contract the virus in Canada.

The provincial government said this weekend that B.C.’s chief veterinarian and public health teams were still investigating the source of exposure, but that it was “most likely” an animal or of a bird.

Human-to-human transmission is very rare, but as cases in animals increase, many experts fear the virus may develop this ability.

The teen was being treated at BC Children’s Hospital on Saturday. The provincial health official said there was no update on the patient Monday.

“I’m obviously very concerned about the young person who was infected,” said Dr. Matthew Miller, director of the Michael G. DeGroote Institute for Infectious Disease Research at McMaster University in Hamilton, Ont.

Miller, who is also co-director of the Canadian Center for Pandemic Preparedness, said several people have been infected with H5N1 in the United States, and almost all of them were ranchers.

In an email to The Canadian Press Monday afternoon, the Public Health Agency of Canada said that “based on current evidence in Canada, the risk to the general public remains low at this time.”

WHAT IS H5N1?

H5N1 is a subtype of the influenza A virus that mainly affects birds. It is therefore also called “bird flu” or “bird flu”. H5N1 influenza, which is circulating widely among birds and livestock this year, is one of several strains of avian influenza known as highly pathogenic avian influenza (HPAI), because it causes serious illnesses in birds, including poultry.

According to the World Health Organization, the H5N1 virus has been circulating widely among wild birds and poultry for more than two decades. The WHO has become increasingly concerned and called for more surveillance of the disease in February 2023 after global reports of the virus spreading to mammals.

HOW FREQUENT IS INFECTION IN HUMAN?

Human infections with the H5N1 virus are rare and “primarily acquired through direct contact with infected poultry or contaminated environments,” the WHO website states.

Before the teen in British Columbia, Canada had recorded a human case of H5N1 in 2014, “travel-related,” according to the Public Health Agency of Canada.

As of November 8, there have been 46 confirmed human cases of H5N1 in the United States this year, according to the Centers for Disease Control and Prevention. There is an ongoing outbreak among dairy cattle, “sporadic” outbreaks on poultry farms and “widespread” cases among wild birds, the CDC website says.

There have been no signs of human-to-human transmission in any of the U.S. cases.

But infectious disease and public health experts worry that the more H5N1 spreads between different types of animals, the more likely it is to mutate and spread more easily among humans.

WHAT ARE THE SYMPTOMS OF H5N1?

Although H5N1 causes symptoms similar to seasonal flu, such as cough, fever, shortness of breath, headache, muscle aches, sore throat, runny nose and fatigue, the strain also has key characteristics that can cause illness. other symptoms.

Unlike seasonal flu, most people infected in the United States have had conjunctivitis, or “pink eye,” Miller said.

One reason for this is probably that many of them worked in the dairy cattle sector.

“In these trafficking operations, it’s easy to contaminate our hands and rub our eyes. We touch our faces all the time without even knowing it,” he said.

“In addition, these operations can produce droplets or aerosols, both during milking and during cleaning, which can enter the eyes relatively easily.”

But the other reason for the conjunctivitis seen in H5N1 cases is that the strain binds to receptors in the eye, Miller said.

While seasonal flu binds to receptors in the upper respiratory tract, H5N1 also binds to receptors in the lower respiratory tract, he said.

“It’s concerning… because if the virus spreads there, these lower respiratory tract infections tend to be much more serious. They tend to lead to more serious consequences, like pneumonia for example, which can cause respiratory distress.” » Miller said.

WILL THE FLU VACCINE PROTECT AGAINST H5N1?

We don’t know “for sure” whether the seasonal flu vaccine could help prevent H5N1 infection, Miller said.

Although there is no data yet, it is entirely possible that it could help prevent more severe illness once a person is infected, he said.

This is because the seasonal flu vaccine contains a component of the H1N1 virus, which “is relatively closely related to H5N1.”

“So the immunity that might help protect people against H5N1 is almost certainly conferred either by prior infection or prior vaccination against the H1N1 virus that circulates in humans,” Miller said.

HOW ELSE CAN I PROTECT MYSELF?

The Public Health Agency of Canada said that, as a general precaution, people should not handle live or dead wild birds or other wildlife, and keep pets away from sick or dead animals. .

Those who work with animals or in places contaminated by animals should take personal protective measures, the agency said.

This report by The Canadian Press was first published November 11, 2024.

The Canadian Press’ health coverage is supported by a partnership with the Canadian Medical Association. CP is solely responsible for this content.