Homologous recombination within the capsid gene of porcine circovirus type 2 subgroup viruses via natural co-infection.

Several studies had reported homologous recombination between two porcine circovirus (PCV) type 2 subgroup viruses, PCV2a and PCV2b. The recombination events described thus far mapped either within the Rep gene sequences or the sequences flanking the Rep gene region. Previously, the presence of both PCV2a and PCV2b DNA sequences in tissues of the same infected swine from the 2005 United States PCV-associated disease outbreak was reported, which indicates that the animal was co-infected with both PCV2 subgroup viruses. Here, two naturally occurring chimeric genomes were identified that exhibited homologous recombination within the capsid gene sequences, and infectious viruses were recovered from both chimeric genomes after transfection into tissue culture cells.