The 2009 swine flu pandemic in North America, part of a pandemic in 2009 of a new strain of influenza A virus subtype H1N1 causing what has been commonly called swine flu, began in the United States or Mexico.
The 2009 swine flu pandemic in North America, part of a pandemic in 2009 of a new strain of influenza A virus subtype H1N1 causing what has been commonly called swine flu, began in the United States or Mexico.
