Federal Veterinary Office, Animal Health Division, Schwarzenburgstrasse 155, CH-3003 Bern, Switzerland.
Vet Microbiol. 2011 Jul 5;151(1-2):153-9. doi: 10.1016/j.vetmic.2011.02.039. Epub 2011 Feb 24.
Switzerland has been officially free of bovine tuberculosis (OTF) since 1960. Since 1980 the control of bovine tuberculosis (bTB) has been reduced to passive abattoir surveillance. Isolated cases of bTB, partly due to reactivation of human Mycobacterium bovis infections with subsequent transmission to cattle, have been noticed in the last years. In Europe, the overall prevalence of bTB is slightly increasing. Both OTF and non-OTF countries report increases in the proportion of bTB positive cattle herds. Current bTB eradication and control programs in Europe are facing a range of challenges. Whole herd depopulation is becoming a less attractive option for economic reasons and due to animal welfare concerns. Live animal trade is increasing both at national and international levels. Regarding these tendencies and taking into account the chronicity of bTB infection, pre-movement testing is becoming increasingly important as a central tool for eradication and for protection against re-introduction of bTB. Pre-movement testing, however specifically focuses on the infection status in individuals, requiring a high level of diagnostic accuracy to correctly diagnose infected animals. Current screening tests for bTB, however, have been designed to meet demands as herd tests. This illustrates that the modification of existing and/or the development of new diagnostics for bTB might be needed. The tuberculin skin test (TST), the primary screening test for bTB may in certain situations have low sensitivity. The interferon gamma (IFN-γ) assay is accepted to be more sensitive compared to TST. Reduced specificity, however, especially in areas of low bTB prevalence raises concerns. New antigen combinations including Rv3615c, OmpATb and others have been shown to complement ESAT-6 and CFP-10 in the whole blood IFN-γ assay and resulted in improved sensitivity (compared to ESAT-6 and CFP-10) and specificity (compared to tuberculins). Lesion detection after slaughter represents a cost-effective procedure for passive surveillance of bTB, especially in areas of low prevalence or in regions free of bTB; however, its sensitivity is very low. This illustrates that trade is linked with a certain risk to re-introduce bTB in OTF regions or countries and that there may be delays in detecting a re-introduction of bTB. In conclusion, regarding the fact that some parameters linked with bTB programs are changing, the development of improved diagnostic tests with a high reliability for use as individual animal tests will be important for future eradication of bTB, in line with international commitment to high standard animal health programs.
瑞士自 1960 年以来已正式消除牛结核病（OTF）。自 1980 年以来，牛结核病（bTB）的控制已减少到被动屠宰场监测。近年来，由于人类牛分枝杆菌感染的再激活以及随后向牛的传播，已注意到 bTB 的孤立病例。在欧洲，bTB 的总体流行率略有增加。OTF 和非 OTF 国家都报告称，bTB 阳性牛群的比例有所增加。目前，欧洲的 bTB 根除和控制计划面临一系列挑战。由于经济原因和动物福利问题，对整个牛群进行扑杀的选择越来越不具有吸引力。由于国家和国际层面的活体动物贸易不断增加。鉴于这些趋势，并考虑到 bTB 感染的慢性，在移动前进行测试作为根除和防止 bTB 再次引入的核心工具变得越来越重要。然而，在移动前进行测试具体侧重于个体的感染状况，需要高水平的诊断准确性来正确诊断感染动物。但是，目前用于 bTB 的筛查测试是为满足牛群测试的要求而设计的。这表明，可能需要修改现有的和/或开发新的 bTB 诊断方法。结核菌素皮肤试验（TST）是 bTB 的主要筛查试验，在某些情况下可能敏感性较低。与 TST 相比，干扰素γ（IFN-γ）检测被认为更敏感。然而，特别是在 bTB 低流行地区，特异性降低引起了关注。已经显示，包括 Rv3615c、OmpATb 在内的新抗原组合与 ESAT-6 和 CFP-10 一起在全血 IFN-γ检测中补充了 ESAT-6 和 CFP-10，从而提高了敏感性（与 ESAT-6 和 CFP-10 相比）和特异性（与结核菌素相比）。屠宰后病变检测是被动监测 bTB 的一种具有成本效益的程序，特别是在低流行地区或无 bTB 地区；但是，其敏感性非常低。这表明，贸易与将 bTB 重新引入 OTF 地区或国家的风险相关联，并且在检测 bTB 的重新引入时可能会出现延迟。总之，鉴于与 bTB 计划相关的一些参数正在发生变化，开发具有高可靠性的改良诊断测试，以便作为个体动物测试使用，对于未来的 bTB 根除将非常重要，这符合国际上对高标准动物健康计划的承诺。
