Figure 2. Phylogenetic relationships of influenza A(H7N9) virus hemagglutinin (HA) and neuraminidase (NA) genes isolated from poultry, Guangdong Province, China, 2014−2015. Phylogenetic trees were constructed by using the neighbor-joining method in MEGA software (http://www.megasoftware.net/). B and C are enlargements of A. Branches of the first, second, and third influenza A(H7N9) virus waves are shown in black, green, and red, respectively. Black triangles indicate newly sequenced viruses isolated from poultry in Guangdong during the third wave. Scale bars indicate nucleotide substitutions per site.