What is avian influenza, or “flu”, and how is it different from a pandemic flu or seasonal flu?
Avian influenza (H5N1) is an infection caused by a highly pathogenic influenza virus that occurs naturally in birds. At this time, it is uncertain whether the H5N1 virus currently circulating in birds will lead to a global disease outbreak (pandemic) in humans.
An influenza pandemic is a global outbreak of disease that occurs when a new influenza A virus appears or "emerges" in the human population, causes serious illness, and then spreads easily from person to person worldwide. Following are some key facts about avian flu:
- Avian flu is caused by avian influenza viruses, which occur naturally among birds but do not typically cause disease in humans.
- In past avian flu outbreaks caused by the H5N1 virus, millions of birds have died or been killed.
- H5N1 flu was first reported to cause severe illness in humans in Asia in 1997.
Additional Information on Avian Influenza
- Please visit the About Pandemics page at the Flu.gov website.
- Information on Avian Influenza - Centers for Disease Control and Prevention (CDC)
- Avian Influenza in Humans - World Health Organization (WHO)
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