Detection of porcine parvovirus using a taqman-based real-time pcr with primers and probe designed for the NS1 gene

Porcine parvovirus (PPV) is an autonomous parvovirus belonging to the genus parvovirus, subfamily Parvovirinae, family Parvoviridae. It is one of the major etiological agents of reproductive failure in pigs. Reproductive failure caused by PPV is characterized by embryonic and foetal death, mummification, stillbirth, and delayed return to oestrus [1]. In addition, PPV has been implicated as the causative agent of diarrhea, skin disease, and arthritis in swine [2]. PPV has been reported from many different countries [3-5].PPV is composed of a linear single-stranded segment of DNA approximately 5 kb long (Molitor, T.W., 1983), and its genome has more than two open reading frames (ORF) [6]. The 3' end of ORF1 encodes nonstructural proteins (NS proteins), and the 5' end of ORF2 encodes structural proteins (VP proteins).For diagnostic purposes, PPV can be rapidly and sensitively detected with polymerase chain reaction (PCR) assays [7,8]. However, current PCR assays for PPV often require multiple steps and do not provide quantitative data. In contrast, real-time PCR using SYBR Green and TaqMan is rapid, specific, and efficient for the large-scale screening, strain identification, and quantification of PPV [9].NS1, which is encoded by the NS1 gene, is a main nonstructural protein of PPV and is associated with the early and late transcription of the virus. Given that inactivated virus used in current vaccines have only little NS1 protein which could not produce antibody, the presence or absence of antibody against NS1 protein could be used in an NS1-based diagnostic kit for determining in clinical settings whether pigs have been vaccinated with the inactivated-PPV or infected with wild-type PPV, and the test would give a negative result for for vaccinated/noninfected pigs. NS proteins are also important in virus research because they play an important regulatory role in viral replication even though they do not directly participate in the assembly of virus particles.In this