Sattler Tatjana, Wodak Eveline, Schmoll Friedrich
Large Animal Clinic for Internal Medicine, University of Leipzig, An den Tierkliniken 11, 04103, Leipzig, Germany.
Institute for Veterinary Disease Control, AGES, Robert-Koch-Gasse 17, 2340, Mödling, Austria.
BMC Vet Res. 2015 Mar 19;11:70. doi: 10.1186/s12917-015-0388-7.
The monitoring of infectious diseases like the porcine reproductive and respiratory syndrome (PRRS) using pen-wise oral fluid samples becomes more and more established. The collection of individual oral fluid, which would be useful in the monitoring of PRRSV negative boar studs, is rather difficult. The aim of the study was to test two methods for individual oral fluid collection from pigs and to evaluate the specificity of a commercial ELISA for detection of PRRSV antibodies in these sample matrices. For this reason, 334 serum samples from PRRSV negative pigs (group 1) and 71 serum samples from PRRSV positive pigs (group 2) were tested for PRRSV antibodies with a commercial ELISA. Individual oral fluid was collected with a cotton gauze swab from 311 pigs from group 1 and 39 pigs from group 2. Furthermore, 312 oral fluid samples from group 1 and 67 oral fluid samples from group 2 were taken with a self-drying foam swab (GenoTube). The recollected oral fluid was then analysed twice with a commercial ELISA for detection of PRRSV antibodies in oral fluid.
All serum samples from group 1 tested negative for PRRSV antibodies. The collection of oral fluid was sufficient in all samples. Sampling with GenoTubes was less time consuming than sampling with cotton gauze swabs. False positive results were obtained in 7 (measure 1) respectively 9 (measure 2) oral fluid samples recollected from cotton gauze swabs and in 9 and 8 samples from GenoTubes. The specificity of the oral fluid ELISA was 97.4% for cotton gauze swabs and 97.3% for GenoTubes. 70 out of 71 serum samples and all oral fluid samples from group 2 tested positive for PRRSV antibodies. The sensitivity of the oral fluid ELISA was 100%. According to the kappa coefficient, the results showed an almost perfect agreement between serum and oral fluid collected in both ways (kappa > 0.8).
Both methods used for individual oral fluid collection proved to be practical and efficient and can be used for PRRSV antibody detection. It has to be considered, however, that false positive results may occur more often than in serum samples.
使用栏位级别的口腔液体样本监测猪繁殖与呼吸综合征（PRRS）等传染病的方法越来越成熟。采集个体口腔液体对于监测PRRSV阴性种公猪群很有用，但却相当困难。本研究的目的是测试两种从猪采集个体口腔液体的方法，并评估一种用于检测这些样本基质中PRRSV抗体的商业ELISA的特异性。因此，用一种商业ELISA对334份来自PRRSV阴性猪的血清样本（第1组）和71份来自PRRSV阳性猪的血清样本（第2组）进行PRRSV抗体检测。用棉纱布拭子从第1组的311头猪和第2组的39头猪采集个体口腔液体。此外，用自干燥泡沫拭子（GenoTube）从第1组采集312份口腔液体样本，从第2组采集67份口腔液体样本。然后用一种用于检测口腔液体中PRRSV抗体的商业ELISA对采集到的口腔液体进行两次分析。
第1组所有血清样本的PRRSV抗体检测均为阴性。所有样本的口腔液体采集量充足。使用GenoTube采样比使用棉纱布拭子采样耗时更少。从棉纱布拭子采集的口腔液体样本中分别有7份（方法1）和9份（方法2）以及从GenoTube采集的样本中有9份和8份出现假阳性结果。口腔液体ELISA对棉纱布拭子的特异性为97.4%，对GenoTube的特异性为97.3%。第2组的71份血清样本中的70份以及所有口腔液体样本的PRRSV抗体检测均为阳性。口腔液体ELISA的灵敏度为100%。根据kappa系数，结果显示两种采集方式获得的血清和口腔液体结果之间几乎完全一致（kappa＞0.8）。
用于采集个体口腔液体的两种方法都被证明是实用且高效的，可用于PRRSV抗体检测。然而，必须考虑到假阳性结果可能比血清样本中更频繁出现。
