Lakew Matios, Srinivasan Sreenidhi, Mesele Beruhtesfa, Olani Abebe, Koran Tafesse, Tadesse Biniam, Mekonnen Getnet Abie, Almaw Gizat, Sahlu Temertu, Seyoum Bekele, Beyecha Kebede, Gumi Balako, Ameni Gobena, Ashenafi Hagos, Bakker Douwe, Kapur Vivek, Gebre Solomon
National Animal Health Diagnostic and Investigation Center, Sebeta, Ethiopia.
Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia.
Front Vet Sci. 2022 Mar 7;9:823365. doi: 10.3389/fvets.2022.823365. eCollection 2022.
Bovine tuberculosis (bTB) is one of the top three, high-priority, livestock diseases in Ethiopia and hence, the need for evaluation of potential control strategies is critical. Here, we applied the test-and-segregate followed by cull strategy for the control of bTB in the intensive Alage dairy farm in Ethiopia. All cattle reared on this farm were repeatedly skin tested using the Comparative Cervical Tuberculin (CCT) test for a total of five times between 2015 and 2021. During the first (October 2015) and second (March 2017) rounds of testing, all reactor animals (>4 mm) were culled, while those that were deemed as inconclusive (1-4 mm) were segregated and retested. At retest, animals with CCT >2 mm were removed from the herd. In the third (December 2017) and fourth (June 2018) rounds of tuberculin testing, a more stringent approach was taken wherein all reactors per the severe mode of CCT test interpretation (>2 mm) were culled. A final herd status check was performed in May 2021. In summary, the number of CCT positives (>4 mm) in the farm dropped from 23.1% (31/134) in October 2015 to 0% in December 2017 and remained 0% until May 2021. In contrast, the number of Single Cervical Tuberculin (SCT) test positives (≥4 mm) increased from 1.8 to 9.5% (from 2017 to 2021), indicating that CCT test might not be sufficient to effectively clear the herd of bTB. However, a more stringent approach would result in a drastic increase in the number of false positives. The total cost of the bTB control effort in this farm holding 134-200 cattle at any given time was conservatively estimated to be ~US$48,000. This, together with the need for culling an unacceptably high number of animals based on skin test status, makes the test-and-cull strategy impractical for nationwide implementation in Ethiopia and other low- and middle-income countries (LMICs) where the infection is endemic. Hence, there is an increased emphasis on the need to explore alternate, affordable measures such as vaccination alongside accurate diagnostics to help control bTB in endemic settings.
牛结核病（bTB）是埃塞俄比亚三大重点家畜疾病之一，因此，评估潜在的控制策略至关重要。在此，我们在埃塞俄比亚的阿拉盖集约化奶牛场应用了检测与隔离随后扑杀的策略来控制牛结核病。2015年至2021年期间，对该农场饲养的所有奶牛总共进行了5次比较颈静脉结核菌素（CCT）皮试。在第一轮（2015年10月）和第二轮（2017年3月）检测中，所有反应动物（>4毫米）均被扑杀，而那些被判定为不确定（1 - 4毫米）的动物被隔离并重新检测。重新检测时，CCT>2毫米的动物被从牛群中移除。在第三轮（2017年12月）和第四轮（2018年6月）结核菌素检测中，采取了更严格的方法，即根据CCT检测解释的严格标准（>2毫米）扑杀所有反应动物。2叭年5月进行了牛群最终状况检查。总之，该农场CCT阳性（>4毫米）的数量从2015年10月的23.1%（31/134）降至2017年12月的0%，并在2021年5月之前一直保持为0%。相比之下，单颈静脉结核菌素（SCT）检测阳性（≥4毫米）的数量从1.8%增加到9.5%（从2017年到2021年），这表明CCT检测可能不足以有效清除牛群中的牛结核病。然而，更严格的方法会导致假阳性数量大幅增加。在任何给定时间存栏134 - 200头牛的这个农场，控制牛结核病的总费用保守估计约为48,000美元。这一点，再加上基于皮试状况需要扑杀数量高得令人无法接受的动物，使得检测与扑杀策略在埃塞俄比亚以及其他感染为地方病的低收入和中等收入国家（LMICs）无法在全国范围内实施。因此，人们越来越强调需要探索替代的、经济实惠的措施，如接种疫苗以及准确的诊断方法，以帮助在地方病流行地区控制牛结核病。
