ABSTRACT
Background:Swine acute diarrhea syndrome coronavirus (SADS-CoV) causes acute vomiting and diarrhea of piglets, leading to significant financial losses in pig industry. Recombinase polymerase amplification (RPA) technology is the second method for nucleic acid amplification under constant temperature conditions besides loop-mediated isothermal amplification (LAMP). The study established a real-time reverse transcription (RT)-RPA assay for early confirmatory diagnoses to detection SADS-CoV.Results:The detection limit of the real-time RT-RPA was 74 copies/µL of SADS-CoV genomic RNA standard in 95% of cases. The assay was performed in less than 30 min and no cross-reactions were observed with 8 other common viruses that affect swine, namely, CSFV, PRRSV, PRV, SIV, SVA, TGEV, PEDV, or PDCoV. The coefficient of variation (C.V.) values of the two standards dilutions and a positive clinical sample ranged from 0 to 4.5%. A total of 72 clinical fecal samples from swine with diarrheal symptoms were analyzed via the developed RT-RPA and qRT-PCR. There was 98.61% agreement between the RT-RPA and the qRT-PCR results. Conclusions:These results indicate that the developed RT-RPA assay has good specificity, sensitivity, stability, and repeatability. In summary, the established RT-RPA assay could satisfy the demand for infield diagnoses, and is suitable for use in remote areas as it is fast, portable, and cost-effective.