Content on this page was developed during the 2009-2010 H1N1 pandemic and has not been updated.
- The H1N1 virus that caused that pandemic is now a regular human flu virus and continues to circulate seasonally worldwide.
- The English language content on this website is being archived for historic and reference purposes only.
- For current, updated information on seasonal flu, including information about H1N1, see the CDC Seasonal Flu website.
Other Flu Web Sites
Influenza A viruses are found in human and many different animals, including ducks, chickens, pigs, whales, horses and seals.
- Seasonal Flu: is a contagious respiratory illness caused by influenza viruses that is common in the Northern Hemisphere in the fall and winter months each year.
- Flu.gov: provides one-stop access to U.S. Government H1N1, avian and pandemic flu information.
- Avian Flu: usually refers to influenza A virus found chiefly in birds, but infections can occur in humans.
- Canine Flu: is a respiratory disease of dogs caused by a specific influenza A virus.
- Swine Flu: is a respiratory disease of pigs caused by type A influenza.
Get email updates
To receive weekly email updates about this site, enter your email address:
Contact Us:
- Centers for Disease Control and Prevention
1600 Clifton Rd
Atlanta, GA 30333 - 800-CDC-INFO
(800-232-4636)
TTY: (888) 232-6348 - Contact CDC-INFO
