Sweeney Raymond W, Whitlock Robert H, McAdams Susan, Fyock Terry
Department of Clinical Studies-New Bolton Center, University of Pennsylvania School of Veterinary Medicine, Kennett Square 19348, USA.
J Vet Diagn Invest. 2006 Jan;18(1):2-6. doi: 10.1177/104063870601800102.
Two thousand nine hundred fifty-two serum samples, collected once or twice annually from 545 cows of known fecal culture status were tested for antibodies to Mycobacterium avium subsp. paratuberculosis using a commercially available enzyme-linked immunosorbent assay (ELISA) test. Overall, 13.5% of the samples from 282 infected cows had positive ELISA results, but when tested multiple times, 38.3% of the cows had at least 1 serum sample with positive results. Among 263 fecal culture-negative cows, 98.1% of the serum samples had negative ELISA results, but when tested multiple times, 7.8% of the cows had at least 1 positive ELISA sample. Fecal culture was positive on a test before the first positive ELISA in 50 cows, ELISA was positive before fecal culture in 12 cows, and in 38 cows, both tests became positive at the same testing time. An additional 174 cows were positive on fecal culture and always negative on ELISA until culled. For cows that had ELISA sample:positive (S/P) ratios below the cutoff point, the change in S/P between sequential tests was evaluated to determine whether a rise in S/P could predict infection status. In this study, change in S/P was not a useful predictor of infection status in seronegative cows.
从545头已知粪便培养状况的奶牛中，每年采集一次或两次共2952份血清样本，使用市售酶联免疫吸附测定（ELISA）检测法检测副结核分枝杆菌抗体。总体而言，来自282头感染奶牛的样本中，13.5%的ELISA检测结果为阳性，但多次检测时，38.3%的奶牛至少有1份血清样本检测结果为阳性。在263头粪便培养阴性的奶牛中，98.1%的血清样本ELISA检测结果为阴性，但多次检测时，7.8%的奶牛至少有1份ELISA检测样本为阳性。在50头奶牛中，粪便培养在首次ELISA检测阳性之前的一次检测中呈阳性，12头奶牛ELISA检测在粪便培养之前呈阳性，38头奶牛在同一检测时间两项检测均呈阳性。另外174头奶牛粪便培养呈阳性，直到被淘汰时ELISA检测始终为阴性。对于ELISA样本S/P比值低于临界值的奶牛，评估连续检测之间S/P的变化，以确定S/P升高是否可预测感染状况。在本研究中，S/P的变化对血清阴性奶牛的感染状况并非有用的预测指标。
