Avian Influenza

Avian influenza (“bird flu”) is caused by the Type “A” influenza virus. This virus can affect several species of food-producing birds (chickens, turkeys, quails, guinea fowl, etc.), as well as pet and wild birds. Avian influenza viruses are generally categorized based on the severity of disease they cause in birds, namely:

  • Low pathogenic avian influenza (LPAI)
  • Highly pathogenic avian influenza (HPAI)

While most avian influenza viruses are low pathogenic, causing little or no signs of illness in birds, some avian influenza viruses are highly pathogenic and can cause severe illness and death in birds. H5N1 Highly Pathogenic Avian Influenza (HPAI) has been has been detected in Canada (opens in new window), including Toronto. The Canadian Food Inspection Agency (CFIA) is responding to cases in farmed birds, backyard poultry and wild birds. See the CFIA’s HPAI monitoring dashboard (opens in new window). If you have backyard hens, practice enhanced infection prevention and biosecurity measures (opens in new window). If you see a sick or dead bird in Toronto, contact 311.

Bird flu is spread by direct contact between infected birds and healthy birds. It can spread when healthy birds come into contact with or interact with equipment (including water and feed) contaminated by the saliva, secretions or feces of infected birds.

Although bird flu mostly spreads among birds, it can spread to other species, such as mammals. While very rare, transmission to humans can occur through exposure to infected birds or contaminated environments, such as live poultry markets. Most avian influenza viruses do not cause disease in humans. Exposure to infected sick or dead animals is the main risk factor for getting avian influenza. Exposure to surfaces contaminated with animal secretions/excretions like saliva, mucus, and animal feces (poop) is another risk. Eating undercooked or uncooked poultry or eggs from an infected bird, or consuming unpasteurized milk from an infected dairy cow, could also be an exposure risk for infection with avian influenza A viruses1.

Bird flu is present in wild bird populations across the world. Typically, wild birds (particularly waterfowl) carry bird flu without symptoms, but they can still spread the virus to domestic birds. Once infected, birds such as chickens, ducks and turkeys may show one or many of these symptoms:

  • Loss or lack of appetite
  • Low energy/tiredness (lethargy) or depression
  • Lack of coordination including tremors
  • Decreased egg production for poultry or pet birds
  • Swelling around the head, neck and eyes
  • Coughing and/or sneezing
  • Other symptoms such as diarrhea, and potentially, sudden death

While rare, humans infected with bird flu have symptoms ranging from conjunctivitis (i.e. red eyes with discharge) to influenza-like illness (i.e. fever, sore throat, muscle aches) to severe respiratory illness and in very rare circumstances, death.

  • Avian influenza is caused by different influenza viruses than the seasonal flu, but some of the symptoms may be similar.
  • Symptoms may appear within 1 – 14 days after exposure to a sick or dead animal.
  • Symptoms can range from very mild to severe, including:
  • fever
  • cough
  • sore throat
  • runny or stuffy nose
  • muscle or body aches
  • headaches
  • fatigue or tiredness
  • conjunctivitis (red eyes)
  • shortness of breath or difficulty breathing

For Toronto Residents

  • There is a vaccine for avian influenza available to eligible high-risk groups.
  • Do not touch wild birds.
  • Avoid contact with domestic birds such as poultry that appear sick or have died.
  • Only keep birds as pets if obtained from a reputable source; do not keep or care for wild birds.
  • Avoid contact with surfaces that have feces from wild or domestic birds.
  • Wash your hands thoroughly with soap and water right away after unavoidable contact with birds or their droppings.
  • Poultry and poultry products such as eggs are safe to eat when food is handled and cooked safely.
  • If you own or care for backyard poultry, there are more steps you can take to protect yourself and your birds from bird flu.
  • If you see a sick or dead wild bird, contact 311. Do not touch sick or dead animals, their feces (poop) or environment (e.g., bedding) or bring sick or dead animals into your home.
  • Report the following sick or dead animals to Toronto Public Health:
    • Domestic Animals (e.g. pets, poultry, and other livestock)
    • Wild birds (e.g. birds, geese, ducks, swans)
    • Wild mammals (e.g. foxes, raccoons, skunks)
    • To report to Toronto Public Health during business hours (8:30 a.m., – 4:30 p.m.), call 416-338-7600
    • To report outside of regular business hours or on holidays, call 311 or 416-392-2489 (if calling outside the City of Toronto boundaries)

For Pet Owners

  • Do not let your pet touch wild birds. Keep your pets away from sick or dead animals and their feces (poop) by keeping them on a leash.
  • Some birds infected with bird flu may not show symptoms.
  • Keep dogs on leash and supervise them closely in designated off-leash areas.
  • Consider keeping cats indoors to prevent contact with wild birds.
  • Do not feed pets (e.g., dogs, cats, etc.) any raw meat from game birds or poultry.
  • Keep pet food and water bowls indoors so they are not accidentally contaminated by birds or other animals.
  • Consider removing backyard bird feeders/baths or move them far away from pets and clean them with 10% bleach at least once every two weeks and then wash your hands.
  • Talk to your veterinarian if you have any concerns about your pet’s health.

Highly pathogenic avian influenza (HPAI) A(H5N1) mainly affects birds but can infect mammals and, rarely, humans. There is no evidence of sustained human-to-human transmission, and the general public risk remains low. 

In June 2025, Health Canada approved the Arepanrix™ H5N1 vaccine for individuals who face ongoing occupational exposure to the virus.  

Eligible high-risk groups for Arepanrix™ H5N1 Vaccine

Due to the low risk of human transmission in Ontario, the vaccine is currently offered only to individuals with ongoing, high-risk exposure to avian influenza A(H5N1), including: 

  1. Those in contact with potentially infected birds: 
  • Wildlife workers, researchers, and rehabilitators handling sick or dead birds  
  • Veterinarians and vet techs exposed to infected birds

     2. Those working with the live virus in labs: 

      • Lab personnel who handle, culture, or manipulate the live H5N1 virus in research, industrial, or clinical settings. 

      The vaccine is a two-dose series, with doses given at least 21 days apart. Summer 2025 is the ideal time to start the series, ahead of increased risk during fall bird migration and to allow spacing from the seasonal flu vaccine. 

      People who receive the H5N1 vaccine are not protected against the yearly seasonal influenza viruses and should still get the seasonal flu shot this fall. 

      A six-week interval between Arepanrix™ H5N1 and other vaccines is recommended, unless urgent immunization is needed. 

      Pregnant or breastfeeding individuals may consider vaccination after discussing the risks and benefits with a healthcare provider. 

      For additional support, talk to your health care provider or Toronto Public Health at 416-338-7600 or call 811 to connect with a registered nurse day or night for free, secure, and confidential health service. To learn more, visit the following:

      1. About Bird Flu | Bird Flu | CDC
      2. Avian flu | ontario.ca
      3. Other Diseases Transmissible from Animals to Humans – City of Toronto
      4. Avian Influenza PPE Guidance for Workers – English