Sequence analysis of the PBoV2 clade showed that their VP1/ VP2 genes were highly diverse and could be classified into two genotypes ( Figure 3 ). The partial NP1 and VP1 genes of PBoV1-H18 related viruses detected in this study were more highly conserved (99-100% identity), consistent with a recent report by Zhai et al reporting PBoV1 in Chinese pigs using partial VP1/ VP2 nested PCR and sequencing [58] . Zhai et al also found a high prevalence of PBoV1 (69% in weanling piglets) with a higher frequency of PBoV1 in animals also infected with PCV2, PRRSV, PTTV or CSFV and in pigs with respiratory symptoms versus healthy pigs [58] .