Abstract
A multiplex reverse transcription polymerase chain rection (mRT-PCR) was developed for simultaneous detection of four RNA viruses in swine. The conserved target sequences directed to classical swine fever virus (CSFV), porcine reproductive and respiratory syndrome virus (PRRSV), porcine epidemic diarrhea virus (PEDV) and transmissible gastroenteritis coronavirus (TGEV) were selected based on alignments of genomic sequences and then specific primers were designed. The mRT-PCR assay was developed and evaluated for its specificity and sensitivity. The expected product from the single viral template was amplified by mRT-PCR and no spurious PCR amplification occurred from the genomic RNA or DNA of other pathogens. For single virus or different combinations of two viruses the detection limit of mRT-PCR was consistent with a single RT-PCR wtith 1 × 10(3) copies. For different combinations of the three viruses or four viruses, sensitivity of PEDV detection partially decreased. All of positive clinical specimens by the mRT-PCR were identically confirmed using Taqman RT-qPCR. Therefore, the mRT-PCR is a useful tool for epidemiological studies and laboratory diagnosis of single virus and/or mixed infections in swine.