Genetic Relationships among Human and Swine Influenza Viruses, 1918-2009

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Genetic Relationships among Human and Swine Influenza Viruses, 1918-2009

human influenza virus lineages diagram

Red arrows indicate human influenza virus lineages, black arrows swine influenza virus lineages, and gray arrows exportation of one or more genes from the avian influenza A virus gene pool. Horizontal bars shown inside the virus represent each of the eight virus genes, abbreviated PB2, PB1, PA, HA, NP, NA, M and NS.
Credit: NIAID

Last Updated June 18, 2009

U.S. Department of Health and Human Services Text