B.C. teen with avian flu is in critical condition, provincial health officer says
CBC News | Posted: November 12, 2024 8:00 PM | Last Updated: November 13
Teenager from Fraser Valley is 1st person to have contracted the H5N1 strain of the virus in Canada
The teenager who tested positive for avian flu is in critical condition and being treated for acute respiratory distress at B.C. Children's Hospital, Provincial Health Officer Dr. Bonnie Henry says.
Henry says the teen, the first presumptive human case of the H5N1 strain of avian flu contracted in Canada, was admitted to hospital late Friday.
Their condition "varied" over the weekend, Henry said, adding "our thoughts continue to be with this person and their family."
Henry said work underway to confirm the diagnosis and trace potential sources of exposure through the B.C. Centre for Disease Control had given her "confidence" that the teen has H5 avian influenza, also known as bird flu.
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She says it's likely that the teenager contracted the illness from exposure to an animal or the environment, although there's a "very real possibility" that the source will never be found.
Henry said privacy considerations restrict what can be said publicly about the teen, but said they did not have any underlying medical conditions.
The teen first went to the emergency department on Nov. 2 and was tested and sent home, but returned to hospital days later when symptoms worsened.
Henry said contact tracing has been conducted on 35 to 40 of the teen's family members, friends and acquaintances.
"We have not identified anyone else that is sick with the virus in B.C. right now," she said. "We don't see right now that there's a risk of a lot of people getting sick."
She said the teen was not in school during the infectious period of the disease, which roughly began on Oct. 31, two days before the onset of symptoms.
She said the teen has no links to people who had recently travelled to Southeast Asia, which has seen outbreaks.
According to Henry, the teen did not have any contact with birds but did interact with a variety of other animals — including a dog, cats and reptiles — in the days before becoming ill. Henry said testing on those animals has so far been negative for the virus.
No detected link to poultry farm outbreaks
She said no links have been found between the teen and local farms — including the two dozen B.C. poultry farms that have suffered avian flu outbreaks during the fall migration of wild birds. No links have been found to outbreaks taking place across the border in Washington state, she added.
Henry said the case is still being called a "presumptive positive" because it has to be confirmed at the National Microbiology Laboratory in Winnipeg, which could happen later on Tuesday.
Infectious disease specialist Dr. Brian Conway said the virus can spread through direct contact with a sick animal, as had been the case with cattle workers in the U.S.
"There's 40 or so [human] cases that occurred in the United States with dairy cattle," he said. "It is [spread by] aerosol, by touch. We can take non-human examples of cats that got it from drinking the contaminated milk from an infected cow."
Human infections rare
While avian influenza infections in humans are rare, Health Canada says symptoms can range from mild to severe, potentially leading to pneumonia, organ failure and even death.
In 2004, two poultry farm workers in the Fraser Valley fell ill with the H7N3 strain of avian flu. According to Public Health Canada, H7N3 typically presents with mild symptoms while H5N1 typically presents as severe.
Since 1997, over 900 human cases have been reported globally, primarily in Asia and Africa, with about half of them resulting in death, according to Health Canada.
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However, the government cautions this fatality rate may be overestimated, as mild infections can often go undetected and underreported.
The Canadian Food Inspection Agency says that, as of Nov. 10, 23 sites in B.C. — mostly commercial poultry operations — are actively dealing with avian flu infections.
Over 6.4 million birds in the province are estimated to have been affected.
Corrections:- A previous version of this story said this was the first human case of avian influenza acquired in Canada. In fact, the case is the first domestically acquired case of the H5N1 strain of avian influenza in this country. Two poultry farm workers in B.C.'s Fraser Valley fell ill with the H7N3 strain of avian influenza during an outbreak in 2004 November 16, 2024 1:23 AM