By Karin Munsterhjelm-Ahumada, M.D. (OMNS, March 20, 2012) The swine flu pandemic of 2009 was caused by a type A influenza (H1N1) virus. This virus was originally referred to as “swine flu” because many of the genes of this new virus were very similar to influenza viruses that normally occur in pigs in North America. The […]