Rovira Albert, Clement Travis, Christopher-Hennings Jane, Thompson Bob, Engle Mark, Reicks Darwin, Muñoz-Zanzi Claudia
Department of Veterinary Population Medicine, College of Veterinary Medicine, University of Minnesota, Saint Paul, MN 55108, USA.
J Vet Diagn Invest. 2007 Sep;19(5):502-9. doi: 10.1177/104063870701900507.
Boar studs are continuously monitored for the presence of porcine reproductive and respiratory syndrome virus (PRRSV) by testing different biological samples by reverse-transcription polymerase chain reaction (RT-PCR). In most cases, samples are run in pools, even though the impact of pooling on the sensitivity of RT-PCR is unknown. The objective of this study was to evaluate the feasibility of using PCR on pooled samples through the estimation of the sensitivity of RT-PCR on different biological samples run individually, in pools of 3 and in pools of 5. Twenty-nine boars were inoculated with a low virulent PRRSV isolate. Serum, blood swab, and semen samples were obtained from each boar every 2 to 3 days for 2 weeks. Each sample was tested by RT-PCR undiluted or diluted 1:3 and 1:5 with negative samples. Eleven of the 29 boars did not appear to get infected from the inoculum, as evidenced by no seroconversion 15 days after inoculation. Data from the other 18 boars showed that serum was the best sample to detect PRRSV during acute infection, with the blood swab sample performing almost as well. Semen samples failed to detect PRRSV infection in most of the cases. Pooling samples at pool sizes of 3 and 5 resulted in a decrease in the sensitivity of RT-PCR. Sensitivity was reduced by 6% and 8%, respectively, when serum or blood swab samples were run in pools of 5. The impact of pooling on the sensitivity of PCR was higher in samples taken during the beginning of the viremic period.
通过逆转录聚合酶链反应（RT-PCR）检测不同生物样本，对公猪站持续监测猪繁殖与呼吸综合征病毒（PRRSV）的存在情况。在大多数情况下，样本是混合检测的，尽管混合样本对RT-PCR敏感性的影响尚不清楚。本研究的目的是通过估计RT-PCR对单独检测、3份样本混合及5份样本混合的不同生物样本的敏感性，来评估对混合样本进行PCR检测的可行性。29头公猪接种了低毒力PRRSV毒株。在2周内，每隔2至3天从每头公猪采集血清、血拭子和精液样本。每个样本用RT-PCR检测，未稀释或用阴性样本按1:3和1:5稀释。29头公猪中有11头似乎未从接种物中感染，接种后15天血清转化阴性证明了这一点。其他18头公猪的数据显示，血清是急性感染期间检测PRRSV的最佳样本，血拭子样本表现几乎同样好。精液样本在大多数情况下未能检测到PRRSV感染。3份样本和5份样本混合会导致RT-PCR敏感性降低。当血清或血拭子样本5份混合检测时，敏感性分别降低了6%和8%。在病毒血症期开始时采集的样本中，混合样本对PCR敏感性的影响更高。
