H1N1 Influenza (Swine Flu)

What Is H1N1 Flu?

H1N1 flu, also called swine flu, is an infection caused by an influenza virus that infects the lungs of pigs. In some cases, the virus can also infect humans and spread from one person to another. Although there is more than one kind of swine flu, the one that concerns health workers is the H1N1 virus.

When you have swine flu, you may feel tired and achy and have a sore throat, a fever, and a cough. Most of the time, the illness is not serious. But severe cases can lead to pneumonia, serious lung problems, and death. If you have another health problem, swine flu can make it worse.

Before 2005, cases of swine flu in people were rare in the United States. But in 2009, the U.S. Centers for Disease Control and Prevention reported an outbreak of a new strain of swine flu in Mexico, the United States, and other countries. This new strain is the H1N1 virus.

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Author:	Deborah Dakins	Last Updated: May 6, 2009
Medical Review:	Martin Gabica, MD - Family Medicine Christine Hahn, MD - Epidemiology W. David Colby IV, MSc, MD, FRCPC - Infectious Disease
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