avian flu

Avian flu is an infectious disease of birds caused by type A strains of the influenza virus. It was first identified in Italy in the early 1900s.

Avian flu is also called bird flu and avian influenza.


Avian flu is caused by a virus. The viruses are complex, with a number of subtypes and strains that vary considerably from one another.

Avian Flu and Birds

Migratory waterfowl and ducks are hosts birds. They carry the viruses that cause bird flu but are often unaffected. Host birds can spread the infection to domesticated chickens, turkeys and geese, resulting in severe epidemics that sicken and kill large numbers of birds, sometimes in a single day.

Avian Flu and Humans

Humans develop avian flu from contact with infected poultry and surfaces contaminated by sick birds. Humans can also develop avian flu from direct contact with another person who has avian flu.

Symptoms of Avian Flu in Birds

The most common symptoms of avian flu in birds are:

  • ruffled feathers
  • reduced egg production
  • respiratory distress

In some cases, domestic birds may die the same day symptoms appear.

Signs in Humans

The most common symptoms of avian influenza in humans are:

  • fever
  • cough
  • sore throat
  • muscle aches
  • eye infections
  • pneumonia


Life threatening complications of avian flu are:

  • viral pneumonia
  • acute respiratory distress syndrome

Treatments and Cure

Currently the most common type of treatments involved antiviral drugs. The CDC currently recommends treatment with a neuraminidase inhibitor for human infection with avian influenza A viruses. Analyses of available avian influenza viruses circulating worldwide suggest that most viruses are susceptible to oseltamivir, peramivir, and zanamivir. However, some evidence of antiviral resistance has been reported in HPAI Asian lineage avian influenza A(H5N1) viruses (“Asian H5N1 viruses”) and Asian lineage avian influenza A(H7N9) viruses (“Asian H7N9 viruses”). Monitoring for antiviral resistance among avian influenza A viruses is crucial and ongoing.