Stories for August 1, 2009
H1N1 influenza, also known as swine flu, is a new strain of flu that has not previously been seen in the United States. Swine flu has been seen in the United States before, but not this strain, which is caused by type A influenza viruses. Outbreaks of swine flu happen regularly in pigs. People do not normally get swine flu, but human infections can and do happen.