1 INTRODUCTION
Bocavirus is a novel classified genus which belongs to the family Parvoviridae , subfamily Parvovirinae , and includes human
bocavirus (HBoV),
porcine
bocavirus (PBoV), canine minute virus (CMV), bovine bocavirus (BPV),
gorillas bocavirus (GBoV), and California sea lion bocavirus (CslBoV)
(Lau et al., 2008; Li et al., 2011). In 2009, porcine boca-like virus
(PBo-likeV) was first reported from lymph nodes of pigs with
post-weaning multi-systemic wasting syndrome (PMWS) in Sweden
(Blomstrom et al., 2009). PBo-likeV was
subsequently discovered in China and named as porcine bocavirus (PBoV)
or PBoV1 in 2010 (Zhai et al., 2010). Since then, PBoV has been
identified in Europe, Asia, North America and Africa
(Zhou et al., 2014).
PBoV is a non-enveloped single-stranded DNA virus which consists of
three open reading frames (ORFs), ORF1, ORF2, and ORF3 (Arthur et al.,
2009). ORF1 encodes a nonstructural protein 1 (NS1 ), ORF2 encodes
viral caspid proteins 1 and 2 (VP1/2 ), and VP1 consists of
the entire VP2 sequence and an additional N-terminal region (Sun
et al., 2009), ORF3 encodes nuclear phosphoprotein 1(NP1 ). Based
on the VP 1 and VP 2 sequences, PBoV has been classified
into different clades, which includes PBoV1, PBoV2, PBoV3, PBoV4, PBoV5,
PBoV3C, PBoV-6V and PBoV-7V. And PBoV was proposed to be classified into
three different groups, PBoV G1, PBoV G2, and PBoV G3
(Zhou et al., 2014).
To date, pigs infected with PBoV have been reported in 20 provinces or
regions in China with the prevalence between 7.3% and 64%
(Wang et al., 2014;
Zhang et al., 2015;
Zhou et al., 2018). Co-infection of PBoV
with other porcine viruses has also been reported, such as porcine
epidemic diarrhea virus (PEDV), porcine circovirus type 2 (PCV2),
pseudorabies virus (PRV), porcine reproductive and respiratory syndrome
virus (PRRSV), porcine torque teno virus (PTTV) and classic swine fever
virus (CSFV) (Blomstrom et al., 2010;
McMenamy et al., 2013;
Zhang et al., 2014;
Huang et al., 2014;
Zhou et al., 2014;
Luo et al., 2015). In addition, PBoV has a
significantly higher infection rate in diseased pigs than in healthy
pigs, and the co-infection rate of PEDV and PBoV was higher in samples
of diarrheal pigs than that of healthy pigs, suggesting that the PBoV
might play an important role in causing diarrhea in piglets
(Zhai et al., 2010). However, the
pathogenicity of PBoV needs further recognized. In the current study, we
aimed to investigate the PBoV prevalence in diarrheal pigs and analyze
full-length genome sequence properties of PBoV from central China.