Swiss Tropical Institute, CH-4002 Basel, Switzerland.
Vet Rec. 2010 Aug 14;167(7):250-6. doi: 10.1136/vr.c3381.
Representative repeated cross-sectional skin testing for bovine tuberculosis (TB) was conducted over a period of three years in a total of 5377 cattle in three randomly selected woredas (districts) in Ethiopia (Meskan, Woldia and Bako-Gazer) that had never previously been tested for TB. Almost all (99 per cent) of the animals included local zebus kept in traditional husbandry systems. The comparative intradermal tuberculin test with two diagnostic thresholds were used to define positive test results, one according to the World Organisation for Animal Health (OIE) recommended cut-off of more than 4 mm, and the other with a cut-off of >2 mm. Data analysis was performed using a logistic regression model with a random effect at the village level. Applying the OIE definition, the overall representative apparent prevalence of bovine TB in skin test-positive local zebus was 0.9 per cent (95 per cent confidence interval [CI] 0.6 to 1.3 per cent). Using a cut-off of more than 2 mm the overall representative prevalence increased to 4 per cent (95 per cent CI 2.4 to 4.8 per cent). Due to the low apparent prevalence, the true prevalence could be calculated only in Meskan (4.5 per cent) and Bako-Gazer (2.4 per cent) for the more than 2 mm cut-off. With the exception of Meskan, prevalence by woreda did not change significantly over the years. Mycobacterium avium reactor animals were found at all study sites, but there were significant geographical variations. Overall, bulls and oxen were more at risk of being positive reactors (odds ratio [OR] 1.6, 95 per cent CI 1.1 to 2.3; OR 2, 95 per cent CI 1.4 to 2.6, respectively), as were animals in good body condition (OR 2, 95 per cent CI 1.5 to 2.9). Similar results were found at woreda level with the exception of Woldia, where none of the analysed variables was significantly associated with a positive test result.
在埃塞俄比亚三个随机选择的沃里达（地区），对从未进行过结核病（TB）检测的 5377 头牛进行了为期三年的牛型结核代表重复横断面皮肤测试。几乎所有（99%）动物都是在传统畜牧业系统中饲养的当地泽布牛。使用两种诊断阈值的比较皮内结核菌素试验来定义阳性试验结果，一种是根据世界动物卫生组织（OIE）建议的超过 4 毫米的截止值，另一种是大于 2 毫米的截止值。数据分析采用村一级随机效应的逻辑回归模型进行。按照 OIE 的定义，皮内试验阳性的当地泽布牛的牛型结核总代表显性流行率为 0.9%（95%置信区间为 0.6%至 1.3%）。使用超过 2 毫米的截止值，总体代表性流行率增加到 4%（95%置信区间为 2.4%至 4.8%）。由于显性流行率较低，只有在超过 2 毫米的截止值下，才能计算 Meskan（4.5%）和 Bako-Gazer（2.4%）的真实流行率。除了 Meskan，各沃里达的流行率多年来没有显著变化。在所有研究地点都发现了禽分枝杆菌反应动物，但存在显著的地理差异。总体而言，公牛和公牛比其他动物更有可能成为阳性反应者（优势比[OR]1.6，95%置信区间为 1.1 至 2.3；OR 2，95%置信区间为 1.4 至 2.6），身体状况良好的动物（OR 2，95%置信区间为 1.5 至 2.9）也是如此。除了 Woldia，在沃里达一级也发现了类似的结果，在那里，没有一个分析变量与阳性试验结果显著相关。
