Our recombination analysis could not reveal the source of mutation (data not shown), although several reports suggested that recombinant viruses belonging to the genus Enterovirus were generated by intra/interspecies transmission [52, 53]. Point mutations in the viral genome are common among picornaviruses because their polymerase lacks the proofreading ability and fidelity of amplification [54–56]. In addition, VP1 is a capsid protein, which likely influences host immunity in infected animals . Therefore, the accumulation of mutations in the viral genome and subsequent selection by immunity in infected hosts may result in the generation of novel species.