2009 Swine-Origin Influenza A (H1N1) Resembles Previous Influenza Isolates

摘要

BackgroundIn April 2009, novel swine-origin influenza viruses (S-OIV) were identified in patients from Mexico and the United States. The viruses were genetically characterized as a novel influenza A (H1N1) strain originating in swine, and within a very short time the S-OIV strain spread across the globe via human-to-human contact.