Swine flu is now the first global pandemic of the 21st century. Swine flu has been renamed Swine-Origin Influenza Virus (S-OIV). Gavin Smith et al. found H1N1 had been consorting with others, shown in a hideous diagram from Ed Yong's update on the situation.
Smith, G., Vijaykrishna, D., Bahl, J., Lycett, S., Worobey, M., Pybus, O., et al. (2009). Origins and evolutionary genomics of the 2009 swine-origin H1N1 influenza A epidemic. Nature DOI: 10.1038/nature08182