Fact checking highly pathogenic avian influenza (HPAI)

June 2025 | Canadian Food Inspection Agency

 

Highly pathogenic avian influenza (HPAI), or bird flu, is a highly contagious viral infection that affects many mammals but primarily impacts wild and domesticated birds, including farmed birds. Managing highly pathogenic avian influenza outbreaks in animal populations is essential for public health, the poultry industry, and the Canadian economy, especially since some wild birds can carry and spread the virus without showing clinical signs.

Recently, misinformation and disinformation about HPAI has downplayed the seriousness of this disease and created confusion about how it is spread, detected, controlled, and prevented. The consequences and severity of HPAI are well-known to Canada’s poultry farmers and processors, veterinarians and animal health experts, but many Canadians have likely seen or heard false or conflicting information about the disease.

Below, we aim to clarify the steps behind Canada’s outbreak response, address some common misconceptions, and explain the science behind the measures in place to protect Canada’s public health, the poultry industry and the economy.

The impacts of HPAI

Since December 2021, the Canadian Food Inspection Agency (CFIA) has been responding to detections of HPAI in commercial and non-commercial farms across Canada. Millions of domestic birds have died from the virus or been humanely culled as part of the ongoing event, which continues to pose significant challenges for farmers, small flock owners, and the poultry industry.

Beyond the immediate impacts on bird health, the virus carries an economic and emotional toll, leading to financial strain and distress for farmers and bird owners. The disruptions extend beyond individual farms, affecting egg and poultry supplies, food security, and international trade. In 2023, Canada’s poultry and egg products were valued at $6.8 billionFootnote 1, including $1.75 billion in exportsFootnote 2.

How Canada responds to HPAI outbreaks

HPAI is a federally reportable disease, which means that bird owners, farmers, veterinarians and laboratories must notify the CFIA of all suspected cases. The CFIA plays a critical role in controlling the spread of the virus and eradicating the disease in Canada’s domestic birds, through the following measures:

  • testing, surveillance and tracing
  • quarantine of infected premises and movement controls for birds, their products and by-products, and things exposed to the birds, into, out of and within a control zone
  • rigorous decontamination, cleaning and disinfection

Canada has a stamping-out policy for HPAI in domestic poultry, which builds from World Organisation for Animal Health (WOAH) Terrestrial Animal Code recommendations. Canada’s stamping out policy helps control the spread of the disease and limit opportunities for virus mutation, reduces exposure to human and wildlife and protects access to international markets.

Key points to clarify on the HPAI response strategy

Why it is necessary to cull infected birds

While controversial to some and often misunderstood, a key part of managing HPAI outbreaks is the humane culling of infected domestic flocks. Once birds are infected with HPAI virus, many become sick and die with no treatment or cure available. Culling methods are quick and humane and aim to minimize suffering and distress.

This measure is also extremely important in limiting spread of the virus and its opportunity to amplify, change and infect other species, including humans. Controlling outbreaks also aims to prevent economic and food supply disruptions for Canadians. This includes safeguarding poultry exports that contribute over a billion dollars to the Canadian economy each year. While culling is a difficult and complex issue, it remains one of the most effective tools in preventing widespread transmission.

Testing and confirmation

When HPAI is suspected, samples are collected and sent to a CFIA-approved laboratory for real-time reverse polymerase chain reaction (RRT-PCR) testing. RRT-PCR tests for avian influenza are highly accurate, with high sensitivity and specificity, allowing for the detection of even low viral loads. Utilization of this test method minimizes the likelihood of false negatives, making RRT-PCR the gold standard for early and reliable diagnosis in both poultry, wild birds, and mammals.

If the results indicate the presence of H5 or H7 subtypes of avian influenza, further confirmation is conducted at the CFIA’s National Centre for Foreign Animal Disease (NCFAD) through full genome sequencing and additional tests. These steps are essential to further characterize the virus (pathogenicity, mutations, genotype, strain, etc.). To confirm that the virus is actively replicating — and not just present as dormant genetic material — scientists place samples into embryonated chicken eggs. These eggs are incubated for several days to allow the virus to multiply. Fluid collected from the eggs is then tested using diverse laboratory methods to confirm the presence of HPAI virus.

Why herd immunity is not an option

Some may wonder why Canada doesn’t rely on herd immunity, or flock immunity, for disease control, but this approach is not viable for HPAI in domestic birds. The virus is highly contagious often with high mortality rates, so infected birds often do not survive. If they do, antibodies may only last for a short period and they may not provide protection against new virus strains.

Infected flocks and their environments become sources of the virus if not quickly destroyed and increase the risks that the virus could spread beyond the farm to other flocks, mammals and humans. Leaving an infection unchecked gives the virus opportunity to survive in the farm environment and would also make it impossible to properly clean and disinfect affected farms. Rapid containment efforts are essential to prevent further harm to Canadian poultry, other animals, and humans.

Why Canada doesn’t currently vaccinate poultry against HPAI

Canada has historically maintained an HPAI response strategy focused on disease eradication and does not currently vaccinate poultry to protect against HPAI. The scale and duration of the ongoing outbreak, however, has increased global interest in exploring vaccination as a tool for disease management. Some countries already use vaccines as a preventative measure.

Introducing a vaccination program is complex and must consider a variety of factors like vaccine efficacy and availability, roll out logistics, surveillance requirements, costs, and potential trade implications.

To address these challenges and explore a potential vaccination program, the CFIA has established the HPAI Vaccination Task Force with representatives from industry, veterinary medicine, academia and government. The group is currently studying the viability and considerations for potentially developing and implementing an HPAI vaccination program in Canada.

Why the risks to humans remain low but not zero

Some human cases of HPAI have been reported worldwide, including a 2024 case in British Columbia, however the risk of HPAI transmission to the general public remains low. Human infections, while rare, have primarily been linked to close contact with infected animals or highly contaminated environments such as farms or live animal markets. Members of the public can prevent this type of exposure by avoiding contact with livestock, live or dead wild birds and wildlife, and refraining from feeding or touching wild animals. Hunters and trappers of wild birds and mammals should also take extra precautions when handling, cleaning and preparing wild game. Always wash your hands after being in an area where birds and other wildlife are living or nesting, and keep pets away from birds, wildlife and their feces.

People who work with infected wild birds or other susceptible wildlife are at increased risk of exposure to avian influenza and should take precautions to protect themselves.

Why HPAI is not a food safety concern

HPAI is not a food safety concern in Canada. The virus is primarily spread through direct contact with live or dead infected birds or by touching contaminated surfaces, and there have been no confirmed human cases of HPAI infection from food consumption. There is no scientific evidence to suggest that consuming thoroughly cooked poultry, game meat, or eggs poses any risk of transmitting avian influenza.

Regardless of HPAI concerns, safe food handling practices, proper hygiene, and thorough cooking of food remain essential.

While HPAI has been detected in dairy cattle in the United States, HPAI has not been detected in dairy cattle or other cattle in Canada. CFIA laboratories have also been monitoring both pasteurized and raw milk for HPAI, and all samples have tested negative. In Canada, milk can only be sold after pasteurization, a process that kills harmful bacteria and viruses, including avian influenza, ensuring that Canadian milk is safe to drink.

The importance of collaboration

With support and cooperation from the poultry industry, Canadian scientists and researchers contribute to global avian influenza monitoring, ensuring early detection of emerging strains and coordinated outbreak responses. At Canada’s WOAH Reference Laboratory for avian influenza, CFIA scientists collaborate with international experts on HPAI and conduct cutting-edge research to better understand the disease and how it spreads. The CFIA’s team of experts in avian diseases plays a key role in addressing technical challenges, gathering critical data, and supporting animal health laboratories across Canada.

Epidemiological studies are also ongoing with collaborations with academia, Environment and Climate Change Canada and provincial partners.

Combatting avian influenza, and misinformation on the disease, requires effective coordination from multiple stakeholders and organizations at the regional, national and international levels. A key strategy for managing avian influenza is ongoing collaboration with regional and global experts to track outbreaks and increase our knowledge of virus strains and affected bird and mammal species.

Learn more about the key collaborators in Canada’s response to HPAI.

It’s important to recognize that science diplomacy and strong international cooperation are crucial for controlling avian influenza. HPAI is a transboundary, One Health issue that requires coordinated efforts to help prevent outbreaks, reduce economic impacts, and protect animal and human health.

The CFIA is dedicated to minimizing the impacts of HPAI to Canada’s domestic birds, poultry farmers and international trade through response measures that are based on the latest scientific evidence, while continuously exploring ways to enhance this response. Humane depopulation, testing, movement controls and rigorous decontamination measures play a vital role in CFIA response to HPAI and help protecting Canada’s agricultural sectors.

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