Appendix. Figure. Phylogenetic tree of the hemagglutinin (HA) gene segment of influenza A (H3) viruses created by using the neighbor-joining method, nucleotide model of Kimura-2 parameters, in MEGA version 4 (10). In addition, a subset of H3 HA gene sequences available in the public domain was included in the analyses for comparison. Red, A/Kansas/13/2009 (H3N2); green, human (H3N2) viruses; black, animal (H3N2) viruses; blue, human cases of swine (H3N2) viruses.