Echovirus plays a major role in natural recombination in the coxsackievirus B group.

Coxsakievirus (CV) B4, CVB5, and CVA9 belong to the species Enterovirus B. These viruses can cause viral encephalitis, aseptic meningitis, pancreatitis, flaccid paralysis, dilated myocarditis, and hand, foot, and mouth disease (HFMD). In order to analyze the evolution of CVB4, CVB5, and CVA9, we analyzed all of the available genome sequences of Enterovirus B (EVB) isolates and found that there were 12 putative recombination events that produced CVB4, 13 putative recombination events that produced CVB5, and 10 putative recombination events that produced CVA9. These recombination events involved 17 EVB serotypes as major or minor parents. The most active Echovirus (EchoV) appears to have been involved in 20 of the 35 recombination events, acting as one of the parental viruses of circulating CVB4, CVB5, and CVA9 strains. Our study indicates that EchoV plays a major role in recombination in the CVB group, and Echov_E30 is the most active in CVB4, whereas Echov_E3 and Echov_E25 are the most active in CVA9.