Parvoviruses are members of the family Parvoviridae and can cause a broad spectrum of diseases in animals . Based on their host range, the family Parvoviridae is classified into two subfamilies: the Parvovirinae subfamily infects vertebrates, while the Densovirinae subfamily infects arthropods. According to the International Committee on Taxonomy of Viruses (ICTV), and recent studies, the subfamily Parvovirinae can be divided into six genera: Parvovirus, Erythrovirus, Dependovirus, Amdovirus, Bocavirus, and a newly proposed genus, Hokovirus [2–5].
Bocaviruses are unique among parvoviruses in the subfamily Parvovirinae, which includes the bovine parvoviruses (BPV), canine minute viruses (CnMV), gorilla bocavirus (GBoV), and four species of human bocaviruses (HBoV1-4) . Bocaviruses contain a non-enveloped, autonomously replicating, single-stranded DNA virus genome, of approximately 5 kb [2, 6–8]. Like other members of the Parvoviridae family, bocaviruses contain the NS1 non-structural protein and the VP1/VP2 structural protein. However, a non-structural NP1 protein encoded by an open reading frame (ORF) in the middle of the genome is a unique structure characterizing bocaviruses, which is absent in most Parvoviridae members .
In 2009, a novel porcine boca-like virus (Pbo-likeV) was discovered in Swedish pigs with postweaning multisystemic wasting syndrome (PMWS) using random amplification and large-scale sequencing technology . Subsequent studies indicated a high prevalence of this novel Pbo-likeV was in weaning piglets with respiratory tract symptoms. Pbo-likeV has also been detected in healthy pigs in China [10, 11].
Pbo-likeV has not been successfully cultured and no serological tests are available, while only conventional PCR assays have been described . In contrast to conventional assays, real-time PCR offers rapid results with potentially increased sensitivity and specificity of detection. It is also less prone to false positive results from amplicon contamination and is more amenable to the quantitative estimation of viral load. Here we report the development of a highly sensitive and specific TaqMan-based real-time PCR assay to target the NP1 gene for the rapid detection and quantitation of Pbo-likeV in clinical specimens.