Development of a real-time reverse transcription loop-mediated isothermal amplification method for the rapid detection of porcine epidemic diarrhea virus

Background: Porcine epidemic diarrhea (PED) is an acute and highly contagious enteric disease characterized by severe enteritis, vomiting and watery diarrhea in swine. Recently, the outbreak of the epidemic disease has been a serious problem in swine industry. The objective of this study is to develop a rapid, sensitive, and real-time reverse transcription loop-mediated isothermal amplification (RT-LAMP) method for the detection of porcine epidemic diarrhea virus (PEDV) in less equipped laboratories. Results: The optimal reaction condition of the current real-time RT-LAMP for PEDV was 62 degrees C for 45 min. It was capable of detecting PEDV from clinical samples and differentiating PEDV from several related porcine viruses, while it did not require additional expensive equipment. The minimum detection limit of the real-time RT-LAMP assay was 0.07PFU per reaction for PEDV RNA, making this assay approximately 100-fold more sensitive than that of one-step RT-PCR. By screening a panel of clinical specimens, the results showed that this method presented a similar sensitivity with real-time RT-PCR and was somewhat sensitive than one-step RT-PCR in detection of clinical samples. Conclusions: In this study, we have developed a new real-time RT-LAMP method, which is rapid, sensitive and efficient to detect PEDV. This method holds great promises not only in laboratory detection and discrimination of PEDV but also in large scale field and clinical studies.