Genetic characteristics of canine bocaviruses in Korean dogs

•CBoV strains causing infections in 83 Korean dogs were surveyed.•Strains 13D003, 13D0095, 14D142, and 14D193 had pathogenicity in young puppy.•These 4 strains also did not contain the ORF region.•Absence of the ORF4 region may influence CBoV pathogenesis in dogs.

To survey for canine bocavirus (CBoV) infection, 83 Korean dogs showing several clinical signs were collected in different provinces from January 2013 to July 2014. Using polymerase chain reaction (PCR) and in situ hybridization, CBoVs were detected in intestine and/or lung samples of 8 dogs (9.6%). To reveal the genetic characteristics of CBoVs, partial or complete regions of CBoVs were sequenced. In phylogenetic trees, 8 CBoVs fell into three clusters. The CBoV strains 13D226-1, 13D250, and 14Q216 were closely related to the CBoV HK831F strain, and the CBoV 14D142 strain was related to the CBoV HK882F strain. Lastly, CBoV 13D003, 13D095, 14D193, and 14Q209 strains were related to CBoV Dis-023, Dis-040, and Dis-046 strains. Interestingly, no canine pathogens were found in dogs in which four CBoVs (13D003, 13D0095, 14D142, and 14D193 strains) were detected and three of them (13D003, 13D095, and 14D193 strains) had a unique deletion (18 nucleotides) in the VP2 gene. Further, the open reading frame 4 (ORF4) region was absent in these 4CBoVs, but found in the other strains, which indicates that the absence of the ORF4 region rather than a unique deletion may have an influence on the pathogenesis of CBoV in dogs.