Commonwealth_ Public-Health officials in British Columbia are investigating the first known human case of H5 avian influenza in Canada, though they have not released many details about the case. Provincial Health Officer Dr. Bonnie Henry announced that the patient is a teenager in the Fraser Valley who is receiving treatment at B.C. Children’s Hospital in Vancouver. Officials are still investigating the teen’s age and current condition, and they believe the virus likely originated from an animal or bird. The investigation has not identified any additional human cases.
The BC Poultry Association, which represents hundreds of poultry farms in the region, has confirmed that if a farm contracts the virus, it does not belong to the association. Shawn Hall, a spokesman for the organization, stated that no human cases of avian flu have been reported among their member farms, which include facilities that produce chicken, turkey, egg, and broiler hatching eggs.
The case has raised alarm among experts. Matthew Miller, Canada Research Chair in viral pandemics and director of the Michael G. DeGroote Institute for Infectious Disease Research at McMaster University, highlighted the significance of the case, particularly given the approaching human flu season. He warned of the potential risk of “re-assortment events,” where multiple flu viruses combine within an infected host, potentially creating new viral strains.
For now, officials in British Columbia and Ottawa maintain that the risk to the general public is low. The Public Health Agency of Canada noted that human-to-human transmission of bird flu remains exceedingly rare, with no evidence of sustained spread between people. However, when humans do contract bird flu, it is often serious; of the nearly 900 confirmed human cases of bird flu globally between 2003 and 2023, 52 percent were fatal.
Dr. Miller and other experts are particularly concerned about the evolution of the H5N1 clade 2.3.4.4b strain, a highly pathogenic variant that has impacted wildlife in North and South America since its detection in Newfoundland in late 2021. The strain has led to the deaths or culling of over 11.7 million farmed birds in Canada across more than 400 farms, according to the Canadian Food Inspection Agency (CFIA). There are currently 24 active avian flu outbreaks on BC farms, many in the Fraser Valley.
This particular strain of avian flu has infected a wide range of animals beyond birds, including bears, cats, foxes, raccoons, marine mammals, and even a pet dog in Ontario that became ill after chewing on an infected wild goose. The United States recently detected the virus in dairy cattle, indicating a troubling expansion to new species. While the virus has not been detected in Canadian cattle, the CFIA has been testing Canadian milk for traces of the virus, though U.S. authorities confirmed that any viral fragments in milk are rendered harmless by pasteurization.
The specific strain that affected the B.C. teen has not been confirmed, but the National Microbiology Laboratory in Winnipeg is conducting tests to verify the subtype. This year, the United States has reported 46 human cases of avian flu, most of which were associated with contact with infected poultry or cattle. None of these cases have been fatal, though some presented as severe conjunctivitis, possibly due to farm workers rubbing their eyes or exposure to contaminated milk.
Dr. Samira Mubareka, an infectious disease physician at Toronto’s Sunnybrook Health Sciences Centre, called the B.C. case “a red flag,” noting the unknown risk of severe disease associated with this particular virus clade. While older strains of H5N1 led to high fatality rates in Asia, the current strain has shown relatively low mortality in the United States, though its effects on younger people, such as the B.C. teen, are not fully understood.
