Coinfection
Poliovirus[edit]
Poliovirus is a positive single-stranded RNA virus in the family Picornaviridae. Coinfections appear to be common and several pathways have been identified for transmitting multiple virions to a single host cell.[13] These include transmission by virion aggregates, transmission of viral genomes within membrane vesicles, and transmission by bacteria bound by several viral particles.
Drake demonstrated that poliovirus is able to undergo multiplicity reactivation.[14] That is, when polioviruses were irradiated with UV light and allowed to undergo multiple infections of host cells, viable progeny could be formed even at UV doses that inactivated the virus in single infections. Poliovirus can undergo genetic recombination when at least two viral genomes are present in the same host cell. Kirkegaard and Baltimore[15] presented evidence that RNA-dependent RNA polymerase (RdRP) catalyzes recombination by a copy choice mechanism in which the RdRP switches between (+)ssRNA templates during negative strand synthesis. Recombination in RNA viruses appears to be an adaptive mechanism for transmitting an undamaged genome to virus progeny.[16][17]