Development and evaluation of a novel reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay for detection of type II porcine reproductive and respiratory syndrome virus.

The objective of this study was to develop a reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay for detection of type II porcine reproductive and respiratory syndrome virus (PRRSV). Based on sequence alignment, four primers were designed amplifying the M gene of type II PRRSV and were subsequently utilized in an RT-LAMP assay. The RT-LAMP product had a ladder-like pattern of bands and the optimal reaction condition for this assay was determined to be 40 min at 63°C. Comparative analysis indicated that the RT-LAMP method was more sensitive than a conventional RT-PCR assay and comparable to a real-time PCR assay. In addition, the RT-LAMP assay was capable of detecting type II PRRSV in field samples and differentiating type II PRRSV from seven other porcine viruses which are all associated frequently with similar clinical symptoms.