Bird flu outbreak hits 32,000 birds at Southwestern Ontario farm
The Canadian Food Inspection Agency 'confirmed the presence of highly pathogenic avian influenza'
Author of the article:Brian Williams
Published Nov 18, 2025 • Last updated 19 hours ago • 3 minute read
The Canadian Food Inspection Agency in Ottawa on Wednesday, June 26, 2019.
The Canadian Food Inspection Agency in Ottawa on Wednesday, June 26, 2019.
The Canadian Food Inspection Agency (CFIA) has declared an avian influenza outbreak after the highly contagious virus was detected at a Southwestern Ontario farm.
The CFIA “confirmed the presence of highly pathogenic avian influenza (HPAI)”, subtype H5N1, at a commercial poultry farm in the municipality of Strathroy-Caradoc on Nov. 14, affecting about 32,000 birds, the agency said in an email statement Tuesday. Due to confidentiality, the CFIA said it does not share details about affected farms.
“All affected birds will be humanely depopulated and disposed of in accordance with all necessary provincial requirements,” the federal agency said, noting it has established a “primary control zone” around the infected premises to prevent the virus from spreading.
“Movements in, within, out, or through (the area) require a permit to move birds, their products, and any by-products,” the CFIA added.
The risk to other birds depends on species, with poultry being “highly susceptible and usually die,” said Scott Weese, an infectious diseases veterinarian and professor at the Ontario Veterinary College at the University of Guelph.
In an email, Weese said the risk to humans is low, with no documented human-to-human transmission.
He cautioned, however, the “big concern” is that H5N1 could continue to mutate or “recombine with a human flu virus” that spreads easily among people. “That’s how all our flu pandemics start,” he said.
Concerns about bird flu transmission grew after a B.C. teen who contracted the virus in November 2024 became seriously ill. The virus has also spread to dairy herds in the U.S.
The Strathroy-Caradoc outbreak is the first in the London region since late February, when an outbreak was declared in the municipality of Middlesex Centre, according to the CFIA website. That outbreak was declared over in May.
Earlier, between Dec. 14 and Jan. 3, seven farms in the London region experienced outbreaks, including two in Strathroy-Caradoc, four in Oxford County, and one in North Middlesex.
Weese said the gaps between outbreaks is likely a “reflection of how good poultry farms are at biosecurity.”
“Flu circulation in birds varies over time and region, but there has to be a jump to poultry or a large, obvious mortality event in wild birds for us to notice something new,” he added. “Circulation of the virus seems to have been lower in Ontario over much of the year, but it’s still a risk.”
The CFIA said the government works with industry and other stakeholders to protect both animal and public health. The agency said “many factors can contribute” to the spread of avian influenza, noting spring and fall pose higher risk for domestic poultry as wild birds migrate and the virus circulates naturally among them and waterfowl.
The continued detection of avian influenza in wild and domestic birds is a “strong reminder for anyone raising birds to remain vigilant of HPAI,” the CFIA said.
Ontario currently has two active bird flu outbreaks, the CFIA’s website stated, estimating that nearly 1.25 million birds have died or been killed since 2021 due to avian influenza.
Weese said culling infected herds “speeds up the inevitable outcome” and allows quicker control on farms.
“The longer an infected group is around, the more risk of transmission to people or other animals, and the more contaminated materials they produce,” he said.
The CFIA could not provide a spokesperson for comment on the Strathroy-Caradoc outbreak as employees identified publicly have “immediately” been targets of harassment and death threats. The agency said the threats came from individuals opposed to its avian influenza eradication policy at the Universal Ostrich Farm in Edgewood, B.C.
Ostriches at the farm began dying last December, but the owners did not alert the CFIA, as required by law.
After an anonymous tip, the CFIA imposed quarantine measures on Dec. 28. Two dead ostriches tested positive on Dec. 31, prompting an immediate cull, which sparked protests, legal challenges, and international attention.
The farm owners sought a judicial review in the months that followed, arguing that the surviving ostriches had “herd immunity” and were valuable for scientific research.
However, on Nov. 6, the Supreme Court of Canada declined to hear the case, and an estimated 300-plus ostriches were culled later that day.
Since late 2021, a total of about 16 million birds across Canada have been killed or died of illness stemming from avian flu, according to the CFIA.
With files from the Canadian Press
bwilliams@postmedia.com
The Canadian Food Inspection Agency "confirmed the presence of highly pathogenic avian influenza."
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