Additional file 2 of Adaptive mutations in HA of avian H9N2 influenza viruses facilitate their transmission to swine

Additional file 2. Differences at the amino acid sequence level between H9 viruses capable and incapable of infecting pigs. The amino acid sequences of H9 viruses were aligned, and the red box highlights differences between strains that are capable and incapable of infecting pigs. ST2030 and JX7554 were unable to infect pigs. NT449, NT10, SSP177W, and YU341 were infective to pigs. The numbering is in accordance with the H3 HA subtype. ST2030: A/Duck/Shantou/2030/2000, JX7554: A/Duck/Jiangxi/7554/2007, NT449: A/Chicken/Hong Kong/NT449/2007, NT10: A/Chicken/Hong Kong/NT10/2011, SSP177W: A/Chicken/Hong Kong/SSP177W/2009, Y341: A/Chicken/Hong Kong/YU341/2008.