FIG 6.

Genotype flow of the influenza A (H7N9) viruses. All H7N9-affected regions are highlighted in light yellow. Two H7N9 sources, the Yangtze River Delta and the Pearl River Delta regions, are highlighted with larger and smaller dotted black triangles, respectively. Dominant genotypes in each source are listed below the corresponding triangles. Virus spreads are indicated by solid arrows. The dotted arrows indicate that the imported H7N9 cases occurred in Taiwan, China, in Malaysia, or in Canada.