PCR Detection And Genetic Variation Analysis Of Canola Virus In Three Areas Of Heilongjiang Province From 2014 To 2015

Canine bocavirus(CBoV) is associated with severe enteritis in dogs. To trace the evolution of CBoV strains circulating in Heilongjiang region of China, 201 fecal samples from rectal swabs of diarrheic dogs collected from May 2014 to April 2015 were investigated using PCR targeting the partial NS1 gene(440 bp) in Harbin, Daqing, Mudanjiang three regions. The VP2 gene of CBoV positive samples were amplified, sequenced and phylogenetic analyzed, and then the evolution of CBoV strains in Heilongjiang area was analyzed. While, the PCR method was used to detect canine parvovirus-2(CPV-2), canine coronavirus(CCoV), canine kobuvirus(CaKV). The PCR results indicated that 15 of the 201 fecal samples(7.5%) were positive for CBoV; the partial NS1 genes of the 15 CBoV strains exhibited 83.1%~100% nucleotide identity, and 75.8%~100% amino acid identity; the VP2 gene of five CBoV strains exhibited 82.9%~96.8% nucleotide identity, and 90.4%~99.1% amino acid identity. Phylogenetic analysis based on the NS1 gene revealed that the 15 CBoV strains from China were divided into different subgroups of CBoV-2 when compared with strains of CBoV-2 from South Korea, USA, Germany, and Hong Kong in China. Moreover, phylogenetic analysis based on the VP2 gene indicated that five selected CBoV strains were divided into three different genetic groups of CBoV-2, involving in CBoV-2HK group, CBoV-2C group, and CBoV-2B group. The recombination analysis using the entire VP2 gene revealed three potential recombination events that occurred among five selected strains in our study. In 15 CBoV positive samples, the high co-infection from 20% to 40% was found between CBoV strains and CPV-2, CCoV, and CaKV strains. Resulting data demonstrated that the positive rate of CBoV in canine diarrhea samples was 7.5%, showed genetic diversities, potential recombination events, and co-infection rate in 3 regions of Heilongjiang.