Development of a fluorescent quantitative real-time polymerase chain reaction assay for the detection of novel-goose parvovirus in vivo

ObjectivesTo develop a sensitive, highly specific fluorescent quantitative real-time PCR assay for accurate detection and quantification of novel-goose parvovirus (N-GPV) in vitro and in vivo. MethodsSpecific primers was designed based on N-GPV inverted terminal repeats region; virus RNA (DFV, NDV, AIV, DHV-1, DHV-3) and virus DNA (MDPV, GPV, N-GPV) were extracted, cDNA (DFV, NDV, AIV, DHV-1, DHV-3) were prepared from viral RNAs using M-MLV Reverse Transcriptase, and prepared cDNA (DFV, NDV, AIV, DHV-1, DHV-3) and DNA (MDPV, GPV, N-GPV) amplified by real-time PCR; the sensitivity, specificity and reproducibility of established real-time PCR methods were evaluated, and finally we validated the reliability of real-time PCR methods in ducklings models in vivo. ResultsThe standard curve of established real-time PCR had a good linearity (slope was -0.3098, Y-intercept was 37.865, efficiency of standard curve was 0.995); the detection limit of established real-time PCR for N-GPV was 10 copies/reaction. The sensitivity of real-time PCR was 10 copies/L, which was 1000 times higher than conventional gel-based PCR assay. The results of intra-assay CVs (0.04-0.74%) and inter-assay CVs (0.16-0.53%) showed that the real-time PCR assay had an excellent repeatability. This method also could efficiently detect viral load in heart, liver, spleen, lung, kidney, pancreas, bursa of Fabricius, brain, blood and excrement from ducklings models after N-GPV infection from 6h to 28 days, which could provided us a dynamic distribution observation of N-GPV viral load using this real-time PCR assay in vivo. ConclusionIn the study, we developed a high sensitive, specific and reproducible real-time PCR assay for N-GPV detection. The established real-time PCR assay was suitable for parvovirus detection and quantification simultaneously, no matter sample obtained from blood, internal organs or ileac contents; the present work may provide insight into the pathogenesis of N-GPV and will contributes to better understanding of this newly emerged novel GPV related virus in cherry valley ducks.