Rapid detection of porcine encephalomyocarditis virus (EMCV) by isothermal reverse transcription recombinase polymerase amplification assays.

In this study, we combined reverse transcription recombinase polymerase amplification assay with the fluorescence detection platform (qRT-RPA) and lateral flow biosensor (LFB RT-RPA) to allow for rapid detection of porcine encephalomyocarditis virus (EMCV). Primers and probes were designed to target the highly conserved region of 3D gene of porcine EMCV. The optimal reaction condition of qRT-RPA and LFB RT-RPA was set as 42 °C for 20 min. The assays were highly specific to EMCV and no cross-reactions were observed with seven other porcine viruses. With a 10-fold serially diluted EMCV genomic RNA as template, the limit of detection was 1.0 × 10 and 1.0 × 10 copies for qRT-RPA assay and LFB RT-RPA assay, respectively. A total of 92 samples from different sources were examined using qRT-RPA, LFB RT-RPA and qRT-PCR. We found 100% diagnostic agreement between qRT-RPA (23/92) and qRT-PCR (23/92), and 97.83% diagnostic agreement between LFB RT-RPA (25/92) and qRT-PCR (23/92). There was no significant difference in performance between the RT-RPA assays developed in this study and a previously described qRT-PCR. However, RT-RPA assays were rapid and easy to perform while LFB RT-RPA exhibited higher sensitivity for EMCV than qRT-PCR. Therefore, the developed EMCV RT-RPA assays provide an attractive and promising tool for effective detection of EMCV in low-resource settings.