USDA, Animal and Plant Health Inspection Service, Veterinary Services, Centers for Epidemiology and Animal Health, Fort Collins, CO 80526-8117, USA.
Prev Vet Med. 2013 Feb 1;108(2-3):234-8. doi: 10.1016/j.prevetmed.2012.08.006. Epub 2012 Sep 12.
Testing of composite fecal (environmental) samples from high traffic areas in dairy herds has been shown to be a cost-effective and sensitive method for classification of herd status for Mycobacterium avium subsp. paratuberculosis (MAP). In the National Animal Health Monitoring System's (NAHMS) Dairy 2007 study, the apparent herd-level prevalence of MAP was 70.4% (369/524 had ≥ 1 culture-positive composite fecal samples out of 6 tested). Based on these data, the true herd-level prevalence (HP) of MAP infection was estimated using Bayesian methods adjusting for the herd sensitivity (HSe) and herd specificity (HSp) of the test method. The Bayesian prior for HSe of composite fecal cultures was based on data from the NAHMS Dairy 2002 study and the prior for HSp was based on expert opinion. The posterior median HP (base model) was 91.1% (95% probability interval, 81.6 to 99.3%) and estimates were most sensitive to the prior for HSe. The HP was higher than estimated from the NAHMS Dairy 1996 and 2002 studies but estimates are not directly comparable with those of prior NAHMS studies because of the different testing methods and criteria used for herd classification.
对奶牛场高流量区域的复合粪便（环境）样本进行检测已被证明是一种具有成本效益且敏感的方法，可用于对分枝杆菌副结核亚种（MAP）的牛群状态进行分类。在国家动物健康监测系统（NAHMS）的 2007 年奶牛研究中，MAP 的明显群体水平流行率为 70.4%（6 个检测样本中，有 369 个复合粪便样本有≥1 个培养阳性）。基于这些数据，使用贝叶斯方法调整检测方法的群体敏感性（HSe）和群体特异性（HSp），估计 MAP 感染的真实群体水平流行率（HP）。复合粪便培养的 HSe 的贝叶斯先验概率基于 NAHMS 2002 年奶牛研究的数据，而 HSp 的先验概率则基于专家意见。基本模型的后验中位数 HP（95%概率区间为 81.6%至 99.3%），估计值对 HSe 的先验值最为敏感。HP 高于 NAHMS 1996 年和 2002 年研究的估计值，但由于用于群体分类的检测方法和标准不同，估计值与之前的 NAHMS 研究无法直接比较。
