Fig. 6. EV-A71 exhibited intensive inter- and intratypic recombination.

A simplified flowchart to illustrate several recombination events identified in this study. The currently circulating EV-A71 B5 strain was derived from the B4 strain, which was an intratypic recombinant virus of EV-A71 genotype B (black rectangle). The previously active EV-A71 B3 strain that carried the CV-A16-like 3D genome also exhibited intratypic recombination (blue rectangle), resulting in the emergence of C4 (#1) and C2-like strains (#2). In addition, intertypic recombination (upper red rectangle) between EV-A71 B3 and several CVs is also shown (#3–6). EV-A71 C4-related intertypic recombination occurred in ~2009 to generate a particular CV-A2 strain (CVA2/SD/CHN/09), which further recombined with CV-A4 to generate the currently circulating CV-A4 (#7 and #8, lower red rectangle). Breakpoints corresponding to the coding nucleotide positions of each recombination event are indicated