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Avian Influenza

Avian Influenza , Image of ducks in flight

What is avian influenza?

  • Avian influenza refers to the disease caused by infection with avian (bird) influenza (flu) Type A viruses. 
  • These viruses occur naturally among wild aquatic birds worldwide and can infect domestic poultry and other bird and animal species. 
  • People do not normally become infected with avian flu viruses, but occasional infections have occurred.
  • Avian Influenza A viruses are classified into two types, low pathogenicity avian influenza (LPAI) A viruses and highly pathogenic avian influenza (HPAI) A viruses. Both LPAI and HPAI viruses can spread rapidly among birds.

    Low Pathogenic Avian Influenza (LPAI):

    • Most avian influenza A viruses are lowly pathogenic and cause few signs in illness in wild birds
    • May cause no or mild signs of illness in chickens/poultry-such as ruffled feathers and a drop in egg production
    • Some LPAI viruses can change (mutate) and become highly pathogenic viruses

    Highly Pathogenic Avian Influenza (HPAI):

    • Highly pathogenic avian influenza viruses cause severe disease and high mortality in infected poultry
    • HPAI viruses most commonly associated with severe disease in poultry include the subtypes of influenza A (H5) and A(H7)
    • HPAI viruses in domestic poultry can spread back into wild bird species, contributing to geographic spread as wild birds migrate to other areas
    • Some HPAI viruses can cause severe disease in wild birds

    The LPAI and HPAI designations do not refer to or relate to illness in people. Both LPAI and HPAI have caused mild to severe illness in infected people.

  • Take Protective Actions Around Birds

    • People rarely get bird flu, but human infections can happen when virus gets into a person's eyes, nose or mouth or gets inhaled from the air.
    • Most human infections with bird flu occur after close, prolonged and unprotected contact with infected birds.
    • Whenever possible, avoid direct contact with wild birds and observe them from a distance.
    • Even healthy-appearing wild birds can carry and spread influenza viruses.
    • Avoid unprotected contact with sick or dead birds-wear gloves and wash your hands with soap and water after removing gloves. Wear a facemask if available.
    • Don't touch surfaces that may be contaminated with saliva, mucous or feces from wild or domestic birds.
    • Everyone 6 months of age and older should get a seasonal flu vaccination every year.

    What To Do If You Find a Dead Bird

    • Domestic poultry:  Michigan Department of Agriculture and Rural Development at 800-292-3939 (daytime); 517-373-0440 (nights, weekends)
    • Wild birds: Michigan Department of Natural Resources at 517-336-5030

    Food Safety

    • The U.S. poultry industry has strict standards, including regular monitoring for bird flu.
    • It is safe to eat properly handled and cooked poultry.
      •  Cooking poultry and eggs to an internal temperature of 165 degrees F kills bacteria and viruses including bird flu.
      • Handle raw poultry safely and wash hands, utensils and surfaces after handling raw poultry and poultry products.

    Protect Your Birds

    USDA Defend the Flock Program - How to protect your backyard flock

    Information for Specific Groups

    Recommendations for Worker Protection and Use of Personal Protective Equipment (PPE)

    Information for People Exposed to Birds Infected with Avian Influenza Viruses

    Information for Hunters


  • Bird Flu and People

    • Avian (bird) influenza (flu) viruses do not usually infect people.
    • In rare cases, human infections have occurred.
    • Symptoms in people can range from no signs to mild illness (red eyes, flu-like upper respiratory signs) to severe disease (pneumonia requiring hospitalization) that results in death.
    • Most human illnesses from bird flu around the world have been due to A(H5) and A(H7) strains of the virus.
    • Virus is shed in the saliva, mucous and feces of infected birds. 
    • People become infected when virus gets into a person's eyes, nose or mouth, or is inhaled from the air.
    • Person to person spread of bird flu is rare. 
    • Public health agencies are interested in detecting human infections with bird flu to monitor the virus for clues that it may be spreading more easily among people.
    • Everyone 6 months of age and older should get an annual influenza vaccination to protect against human influenza viruses that normally circulate every year.

    How is Bird Flu in People Diagnosed?

    • The symptoms of bird flu can be similar to other common illnesses in people.
    • Laboratory testing is needed to make a diagnosis bird flu.
    • A swab is collected from the upper respiratory tract (nose or throat) of a sick person.
    • Samples are tested for influenza viruses that commonly infect people.  
    • When a bird flu virus is suspected based on the patient's risk for exposure and inconclusive testing for Influenza A virus, the sample is sent for more specialized testing that can detect stains of bird flu.

    How is Bird Flu in People Treated?


  • USDA Surveillance-Detections of HPAI in Commercial, Backyard, and Wild Birds

    CDC: Reported Human Infections with Avian Influenza a Viruses

    World Health Organization: Influenza at the human-animal interface Monthly Risk Assessment Summaries

  • USDA Newsroom

    Michigan Department of Agriculture Media Room

    CDC:  Bird Flu Current Situation Summary