What is avian influenza, or “flu”, and how is it different from a pandemic flu or seasonal flu?

Avian influenza (H5N1) - commonly called "bird flu" - 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, or “bird flu,” is caused by avian influenza viruses, which occur naturally among birds but do not typically cause disease in humans.
• In the current avian flu outbreak caused by the H5N1 virus, millions of birds have died or been killed.
• H5N1 bird flu was first reported to cause severe illness in humans in Asia in 1997.
• Affected areas with confirmed human cases of
  H5N1 avian influenza since 2006.

• For cumulative number of confirmed human cases of Avian Influenza A/(H5N1) reported to WHO (World Health Organization), go to: http://www.who.int/csr/disease/avian_influenza/en/index.html.
• No human cases of H5N1 avian influenza have occurred in the U.S.

Additional Information on Avian Influenza (Bird Flu)  

• WHO Guidelines for Investigation of Human Cases of Avian Influenza A(H5N1) (World Health Organization)
  The Guidelines provide a framework and approach for public health authorities and investigators at all levels, to plan for and conduct investigations of human cases of A(H5N1) (or other avian influenza viruses of pandemic potential). The document focuses on the key steps that should be undertaken in an investigation.
• Key Facts About Avian Influenza (Bird Flu) and Avian Influenza A (H5N1) Virus - Center for Disease Control (CDC) 
• Avian Influenza Frequently Asked Questions - World Health Organization (WHO) 

For more information of pandemic influenza, send us an email at fluinfo@sbcphd.org or follow us on Twitter at SBCPublicHealth.