Enterovirus C recombination groups: RNA sequence similarity and the viral polymerase underpin sexual replication mechanisms

Viral RNA recombination transforms live-attenuated polioviruses into neurovirulent circulating vaccine-derived polioviruses, complicating the planned eradication of poliovirus. When humans are co-infected with poliovirus and related non-polio enteroviruses, viral replication machinery can produce recombinant viruses. However, who recombines with whom? What factors determine whether two distinct viruses can produce recombinant progeny that are fit for transmission from person to person? In this study, we clarify which viruses recombine with one another in nature and further elucidate the mechanisms by which the viral polymerase distinguishes between related and unrelated RNA templates-a sexual form of replication. Understanding these mechanisms could lead to better strategies for virus control and/or eradication.