A TaqMan-based real-time PCR for detection and quantification of porcine parvovirus 4

Porcine parvovirus 4 (PPV4) is a DNA virus, and a member of the Parvoviridae family within the Bocavirus genera. It was detected recently in swine, but its epidemiology and pathology remain unclear. A TaqMan-based real-time PCR (qPCR) targeting a conserved region of the ORF3 gene of PPV4 was developed. The qPCR detection limit was 9.5 × 101 DNA copies/μL. There was no cross-reaction with porcine parvovirus, torque teno virus 1, torque teno virus 2, porcine circovirus type 1, porcine circovirus type 2, or with pseudorabies virus. Two hundred and seventy-two samples, including serum, semen, lungs, feces, ovarian follicular fluids, ovaries and uterus, were evaluated by qPCR and PPV4 was detected in 36 samples (13.2%). When compared with a conventional PCR (cPCR), the qPCR assay was 10 times more sensitive and the detection of PPV4 DNA in field samples was increased 2.5 times. Partial sequencing of PPV4 ORF3 gene, obtained from two pooled samples of uterus and ovaries, revealed a high nucleotide identity (98-99%) with a reference PPV4 sequence. The qPCR can be used as a fast and accurate assay for the detection and quantification of PPV4 in field samples and for epidemiological studies in swine herds.