Diagnostics, Research and Epidemiology, Animal Health Service Deventer, The Netherlands.
Vet Microbiol. 2010 Dec 15;146(3-4):209-14. doi: 10.1016/j.vetmic.2010.05.009. Epub 2010 May 10.
After the introduction of bluetongue virus serotype 8 (BTV-8) in western Europe in 2006, an indirect ELISA for detection of serogroup-specific antibodies against BTV in serum samples was validated for individual milk samples by the Central Veterinary Institute and the Animal Health Service in the Netherlands (Kramps et al., 2008). In order to develop a cost-effective monitoring tool, we now have evaluated this ELISA also for use in bulk milk. Therefore, bulk milk samples and individual milk samples were collected from 92 herds in the affected southern region in the Netherlands in 2007, before the start of the vaccination campaign. In addition, bulk milk samples collected from 88 herds before the bluetongue introduction in 2006 ("historically negative" samples) have been tested. With these results ROC analyses were performed and herd specificity and herd sensitivity of the bulk milk ELISA were estimated. All "historically negative" bulk milk samples were negative in the ELISA, with a mean S/P ratio of 10 ± 0.8%. The herd sensitivity and herd specificity of the ELISA in bulk milk samples depend on the cut-off that is chosen. In order to detect a within-herd-prevalence of 1%, the optimal cut-off S/P ratio 13% was found. A few herds with one or two milk-positive animals would then be missed. The specificity will be 100%. A within-herd-prevalence of 10% can be detected with 100% sensitivity at a cut-off S/P ratio of 96%. In conclusion, the indirect ELISA in bulk milk samples is a very specific and sensitive test which can be implemented in monitoring and surveillance systems in unvaccinated populations.
自 2006 年西欧引入 8 型蓝舌病毒（BTV-8）以来，荷兰中央兽医研究所和动物健康服务处已经验证了一种用于检测血清样品中 BTV 血清群特异性抗体的间接 ELISA 方法，适用于个体奶样（Kramps 等人，2008 年）。为了开发一种具有成本效益的监测工具，我们现在还评估了该 ELISA 在牛奶混合物中的应用。因此，2007 年在荷兰受影响的南部地区，在开始疫苗接种活动之前，从 92 个牛群中采集了牛奶混合物和个体奶样。此外，还对 2006 年蓝舌病引入前从 88 个牛群中采集的牛奶混合物样本（“历史阴性”样本）进行了测试。利用这些结果进行了 ROC 分析，并估计了牛奶混合物 ELISA 的牛群特异性和牛群敏感性。所有“历史阴性”的牛奶混合物样本在 ELISA 中均为阴性，平均 S/P 比值为 10 ± 0.8%。牛奶混合物 ELISA 的牛群敏感性和牛群特异性取决于所选择的截止值。为了检测 1%的牛群内流行率，发现最佳的截止 S/P 比值为 13%。那么一些只有 1 头或 2 头牛奶阳性动物的牛群将被遗漏。特异性将为 100%。在截止 S/P 比值为 96%时，可以检测到 10%的牛群内流行率，同时具有 100%的敏感性。总之，牛奶混合物中的间接 ELISA 是一种非常特异和敏感的检测方法，可以在未接种疫苗的人群的监测和监测系统中实施。
