Comparative evaluation of commercial multiplex real-time RT-PCR kits for differential detection of PRRSV-1, PRRSV-2, and PCV2 currently circulating in Korean pig farms

초록

The genetic diversity of porcine reproductive and respiratory syndrome virus (PRRSV) and porcine circovirus 2 (PCV2) complicates diagnosis and control of these viral infections. Several multiplex real-time quantitative reverse transcription-polymerase chain reaction (mqRT-PCR) kits for the differential detection of PRRSV-1, PRRSV-2, and PCV2 are commercially available, but it is unclear which kits are more suitable for detecting field strains of the viruses currently circulating in Korean pig herds. In this study, the diagnostic performance of a newly launched mqRT-PCR kit (N kit) that can differentially detect PRRSV-1, PRRSV-2, and PCV2 was evaluated by comparing it with four other commercial mqRT-PCR kits (A, B, C, and D) currently available in Korea. The preliminary evaluation results showed that the N kit was highly specific for differentially detecting target genes of the three viruses in a single reaction. The assay was highly sensitive with a detection limit of <10 copies/reaction and was highly precise with intra- and inter-assay coefficients of variation of <3.2%. In the clinical evaluation using 160 clinical samples, the N kit detected PRRSV-1, PRRSV-2, and PCV2 in 46.9%, and 70.0%, and 61.3% of the samples tested, respectively. The detection rates of PRRSV-1, PRRSV-2, and PCV2 by the N kit were higher than those of the A kit (29.4%, 61.3%, and 34.4%, respectively), B kit (29.4%, 41.3%, and 36.9%, respectively), and C kit (40.0%, 61.9%, and 50.6%, respectively), and D kit (36.9%, 31.3%, and 50.6%, respectively). In addition, the N kit showed the highest detection rate of 21.9% in diagnosing mixed infections with three viruses, which was much higher than those of the other four kits (5.6% to 7.5%). All these results demonstrated that the diagnostic performance of the N kit for PRRSV-1, PRRSV-2, and PCV2 was superior to that of four existing commercial kits. Considering the negative impacts of misdiagnosis of important viral pathogens such as PRRSV and PCV2 on pig farms, it is very important to select and use the most appropriate diagnostic method for these viral pathogens. In this regard, the N kit, which showed excellent diagnostic performance, is highly recommended for the exact and reliable diagnosis of PRRSV-1, PRRSV-2, and PCV2 field strains currently circulating in Korean pig herds. This study is the first to compare the diagnostic performance of five commercial diagnostic kits for PRRSV-1, PRRSV-2, and PCV2 currently available in Korea, providing valuable information for selecting the most appropriate diagnostic kit for these viral infections in Korea.

키워드