A novel porcine bocavirus harbors a variant NP gene

BACKGROUND: Porcine bocavirus is classified within the genus Bocaparvovirus, family Parvoviridae. Unlike other parvoviruses, the members of genus Bocaparvovirus (bocaparvoviruses) encode an additional open reading frame (NP1). Many strains of PBoVs have been identified in domestic pigs and recognized as a potential emerging pathogen causing respiratory and gastrointestinal disease. FINDINGS: A new strain of porcine bocavirus (PBoV) that harbored the shortest NP1 gene among all currently characterized PBoVs (provisionally named as ‘PBoV-KU14’) was detected in domestic pigs. Almost the complete genome sequence was obtained, approximately 4,630 nucleotides in lengths with putative NS1, NP1, and VP1/2 genes of 1,908, 600, 1,851 bp, respectively. Phylogenetic and comparative analysis was performed using protein and nucleotide sequences. It was revealed that PBoV-KU14 belongs to the genus Bocaparvovirus and species Ungulate bocaparvovirus 4. However, phylogenetic incongruence was observed among species classifications based on the NS1, NP1 and VP1/2 proteins, which indicates a probability of crossover recombination. Conserved protein domains unique for genus Bocaparvovirus in NP1, VP1 protein were also detected. CONCLUSION: NP1 gene truncation supposed to be caused by cross over recombination was detected in a new strain of PBoV (PBoV-KU14). Considering high rates of substitution and recombination in parvovirus, periodic surveillance study to monitor genomic variation and find new strainsof PBoVs seems to be needed.