Question Period Note: Avian Influenza

N/A

Avian influenza (AI) viruses, such as the A(H5N1) virus strain, are circulating globally and mainly affect birds. An unprecedented global outbreak of A(H5N1) in wild birds and poultry has been ongoing since late 2020, spreading to Canada in the fall of 2021, with increasing detections in wild mammals, and sporadic human cases outside of Canada.
Key Messages
• There has been no human-to-human transmission identified with A(H5N1) virus and no confirmed human cases associated with the current A(H5N1) situation have been detected in Canada.
• The risk to the general population remains low.
• Individuals with close contact with potentially infected animals, for example through farming or hunting, are at increased risk compared to the general population due to the higher probability of exposure and should take appropriate precautions.
• The Public Health Agency of Canada, together with federal partners, the provinces, territories, and international partners, will continue to monitor the situation and keep Canadians informed, particularly about confirmed human cases of A(H5N1).

If pressed on the risk to humans:
• A(H5N1) cases in humans are rare and usually only occur in people that have close contact with infected birds or heavily contaminated environments.
• Current scientific evidence suggests the risk of a human contracting avian influenza from a domestic pet (e.g., cat, dog) is low based on the current evidence globally.
• There is no evidence to suggest that eating thoroughly cooked poultry or eggs could transmit A(H5N1) to humans.

According to the Public Health Agency of Canada’s Human Emerging Respiratory Pathogens Bulletin, there have been 892 cases of human infection with avian influenza A(H5N1) virus reported globally since 1997. Of these 892 cases, 464 were fatal (a case fatality rate of 52%).
Since December 20, 2021, A(H5N1) has been detected in wild birds in all provinces and territories in Canada. Additionally, since February 2022, the Canadian Food Inspection Agency has reported cases of A(H5N1) in domestic bird flocks in 9 provinces (Newfoundland and Labrador, Nova Scotia, New Brunswick, Quebec, Ontario, Manitoba, Saskatchewan, Alberta, and British Columbia).
Detections of A(H5N1) in wild mammals, such as foxes, skunks, raccoons, and bears are not unexpected given these species are known to eat wild birds. However, there appears to be an increase in the number of reported wild mammal detections compared to previous outbreaks, likely due to the prolonged duration and extensive geographic spread of the current A(H5N1) outbreak. Detections of A(H5N1) in domestic pets (e.g., cats, dogs) that may eat or scavenge on infected birds are also not unexpected. Current scientific evidence suggests the risk of a human contracting avian influenza from a domestic pet is low.

• A significant number of A(H5N1) detections associated with the current 2021-2023 global outbreak in birds have been reported in domestic, backyard, and wild bird populations across Canada. There have also been A(H5N1) detections in wild mammals (such as foxes, skunks, seals, bears, raccoons, river otters, dolphins, porpoise, and wild mink) across Canada.
• On April 1, 2023, the Canadian Food Inspection Agency confirmed that a domestic dog in Oshawa, Ontario tested positive for A(H5N1) after it had scavenged a dead infected wild goose. The dog has since died.
• On May 2, 2023, a feral cat with A(H5N1) was also reported in Ontario.
• As of May 10, 2023, 11 human cases of A(H5N1) have been reported in the UK (1), Spain (2), the United States (1), Vietnam (1), China (2), Ecuador (1), Cambodia (2) and Chile (1). Three of the cases had no signs of illness, two had mild illness, and six were severe with two fatalities. Ten cases had a history of exposure to domestic poultry but the case from Chile was believed to be due to environmental contamination.
• In February 2023, two human cases of A(H5N1) in Cambodia sparked concern of potential human-to-human transmission; however, an investigation determined that the individuals were both exposed to infected birds and there was no human-to-human transmission. It was also confirmed that the strain of virus in these cases was different from those currently circulating in wild birds and poultry in Canada and the U.S.
• In 2014, Canada (Alberta) reported one single fatal case of A(H5N1) in a resident returning from travel in China.