Development of a SYBR Green based real-time PCR assay for detection and quantitation of canine parvovirus in faecal samples.

The present study describes the development of SYBR Green based real-time polymerase chain reaction (real-time PCR) for detection and quantitation of canine parvovirus type 2 (CPV 2) in faecal samples of dogs. In this assay, the primers were designed and custom-synthesized based on nucleotide sequence of VP2 gene of CPV 2. A standard curve was plotted using 10-fold serial dilution of standard plasmid DNA and Ct value. The standard curve was found to be linear over a 10(-7) dilution. The real-time PCR results were expressed as the number of DNA copies of CPV 2 per mg of faecal samples and showed range of 1.0 x 10(3) to 7.0 x 10(9) copies of viral DNA per mg of stool samples. The analytical sensitivity of the SYBR Green based real-time PCR was shown to be equivalent to 10 copies. Faecal samples (47) from dogs suspected of CPV 2 infection were analyzed by real-time PCR, haemagglutination (HA) assay and by a conventional PCR and 24, 20 and 22 samples were found positive for CPV 2, respectively. Comparison between the results of three different assays revealed that real-time PCR is more sensitive than HA and conventional PCR and allow the detection of low titers of CPV 2 in infected dogs.