Abstract
To investigate the epidemic profile and genetic diversity of porcine
bocavirus (PBoV), 281 clinical samples including 236 intestinal tissue
samples and 45 fecal samples were collected from diarrheal piglets in 37
different pig farms of central China, and two SYBR Green I-based
quantitative PCR assays were developed to detect PBoV1/2 and PBoV3/4/5
respectively. The results showed the detection limits of two assays were
1.66 × 101 genome copies/μl of PBoV1/2 and 3.3 × 101 copies/µL of PBoV
3/4/5. 148 (52.67%) of the 281 clinical samples were positive for
PBoV1/2, 117 (41.63%) were positive for PBoV3/4/5, 55 (19.57%) were
positive for both PBoV1/2 and PBoV3/4/5, and 86.49% (32/37) of the pig
farms were positive for PBoV. Subsequently, complete genomic sequences
of two PBoV strains (designated CH/HNZM and PBoV-TY) from two different
farms were sequenced. The phylogenetic analysis demonstrated that the
two PBoV strains obtained in this study belonged to the PBoV2 group and
had a close relationship with other 12 PBoV2 strains, but differed
genetically from PBoV1, PBoV3/4/5 and 7 other bocaviruses. CH/HNZM and
PBoV-TY were closely related to the PBoV strain GD18 (KJ755666) which
may be derived from PBoV strains 0912/2012 (MH558677) and 57AT-HU
(KF206160) through the recombination analysis. Compared with reference
strain ZJD (HM053694)-China, a higher amino acid variation was found in
the NS1 protein of CH/HNZM and PBoV-TY. These results extend our
understanding of the molecular epidemiology and evolution of PBoV.