Bead-based suspension array for simultaneous differential detection of five major swine viruses

A novel multiplex detection array based on Luminex xMAP technology was developed and validated for simultaneous detection of five major viruses causing swine reproductive diseases. By combining one-step asymmetric multiplex reverse transcription polymerase chain reaction (RT-PCR) with xMAP bead-based hybridization and flow cytometry analysis, the resulting multiplex assay was capable of detecting single and mixed infections of PRRSV, PCV-2, PRV, CSFV, and PPV in a single reaction. The assay accurately detected and differentiated 23 viral strains used in this study. The low detection limit was determined as 2.2-22 copies/μL (corresponding to 0.5-6.8 fg/μL DNA template) on plasmid constructs containing viral fragments. The intra-assay and inter-assay variances (CV%) were low that ranged from 2.5 to 5.4 % and 4.1 to 7.6 %, respectively. The assay was applied to test field samples and detected single and mixed viral infections. The detection rate was higher than that of uniplex conventional PCR and RT-PCR methods. The detection of PRRSV by the bead-based multiplex assay was comparable with a commercially available real time RT-PCR kit. The test procedure on purified DNA or RNA samples could be completed within 2 h. In conclusion, the bead-based suspension array presented here proved to be a high-throughput practical tool that provided highly specific and sensitive identification of single and multiple infections of five major viruses in pigs and boar semen.