Rapid detection of novel caprine parainfluenza virus type 3 (CPIV3) using a TaqMan-based RT-qPCR

Parainfluenza virus type 3 (PIV3) is one of the most important respiratory pathogens for humans and many animals. A novel caprine PIV3 (CPIV3) was recently identified and isolated from Chinese goat flocks with respiratory disease. In order to develop rapid and sensitive methods for CPIV3 detection in infected goats, a TaqMan RT-qPCR was established in this study based on the primers and probe designed to amplify a 150 nucleotide-long region located within the M gene of the virus. The method was able to detect about 1.0×10(1) DNA copies/μL with an efficiency of 99.6% and a R(2) value of 0.997. There were no cross-reaction observed using this technique against peste des petits ruminants virus (PPRV), border disease virus (BDV), bluetongue virus (BTV) and bovine viral diarrhea virus (BVDV). One hundred and fourteen samples, including nasal swabs, feces swabs, sera, hearts, livers, spleens, lungs, kidneys, tracheas and hilar lymph nodes (HLNs) from six challenged goats, were evaluated by this technique. Using TaqMan RT-qPCR, CPIV3 was positively detected in 51 of 114 samples (44.74%), which was higher than RT-PCR (27.19%, 31/114) and virus isolation (14.9%, 17/114), respectively. The method also gave higher positive detection rate (35%, 42/120) than RT-PCR (28.33%, 34/120) from clinical samples. These data indicated that this method could be used for faster and more accurate monitoring of viral load, disease progression and vaccination efficacy of CPIV3 in goat flocks.