Probe-based real-time reverse transcription loop-mediated isothermal amplification (RRT-LAMP) assay for rapid and specific detection of foot-and-mouth disease virus

Rapid and specific detection of foot-and-mouth disease virus (FMDV) is a key factor for promoting prompt control of FMD outbreaks. In this study, a real-time reverse transcription loop-mediated isothermal amplification (RRT-LAMP) assay with high sensitivity, rapidity and reliability was developed using a targeted gene-specific assimilating probe for real-time detection of seven FMDV serotypes. Positive assay signals were generated within 15 min for the lowest concentration of a standard RNA sample at 62°C; this was substantially faster than that achieved by the OIE (World Organisation for Animal Health)-recommended real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) assay. The new assay specifically amplified the 3D gene of all seven FMDV serotypes and did not amplify other viral nucleic acids. The detection limit of the assay was 102 copies/µl which is comparable to that achieved by qRT-PCR. Furthermore, using clinical samples, the results of the RRT-LAMP assay were largely in agreement with those from the qRT-PCR assay with a kappa value (95% confidence interval [CI]) of 0.94 (0.86-1.02). The established RRT-LAMP assay that features assimilating probes is an advanced molecular diagnostic tool that is easily applicable to a wide range of circumstances and has high potential for use as an on-site diagnostic assay for rapid, specific, and reliable detection of FMDVs in clinical samples.