A Duplex SYBR Green I-based Real-time Polymerase Chain Reaction Assay for Rapid Detection of Canine Kobuvirus and Canine Circovirus

Abstract

Background: Canine Kobuvirus (CaKoV) and Canine Circovirus (CaCV) are viruses that infect dogs causing diarrheal symptoms that are very similar. However, there is no clinical method to detect a co-infection of these two viruses.Results: In this study, a duplex SYBR Green I-based quantitative real-time polymerase chain reaction (PCR) assay for the rapid and simultaneous detection of CaKoV and CaCV was established. CaKoV and CaCV were distinguished by their different melting temperature which was 86℃ for CaKoV and 78℃ for CaCV. The assay was highly specific, with no cross-reactivity with other common canine viruses and demonstrated high sensitivity. The detection limits of CaKoV and CaCV were 8.924 × 101 copies/μL and 3.841 × 101 copies/μL, respectively. The highest intra- and inter-assay Ct value variation coefficients (CV) of CaKoV were 0.40% and 0.96%, respectively. For CaCV, the highest intra- and inter-assay Ct value variation coefficients were 0.26% and 0.70%, respectively. In 57 clinical samples, positive detection rates of CaKoV and CaCV were 8.77% (7/57) and 15.79% (9/57), respectively. The co-infection rate was 7.02% (4/57). Conclusions: The duplex SYBR Green I-based real-time PCR assay established in this study is a fast, efficient, and sensitive method for the simultaneous detection of the two viruses and provides a powerful tool for the rapid detection of CaKoV and CaCV in clinical practice.