Department of Bacteriology, Animal and Plant Health Agency, Woodham Lane, New Haw, Addlestone, Surrey, KT15 3NB, United Kingdom.
Department of Bacteriology, Animal and Plant Health Agency, Woodham Lane, New Haw, Addlestone, Surrey, KT15 3NB, United Kingdom.
Prev Vet Med. 2020 Jul;180:105005. doi: 10.1016/j.prevetmed.2020.105005. Epub 2020 Apr 19.
Bovine tuberculosis (bTB), caused by Mycobacterium bovis, represents a major animal health issue. In the United Kingdom and the Republic of Ireland, European badgers (Meles meles) have been shown to act as a reservoir of M. bovis infection, hindering the eradication of bTB in livestock. The availability of suitable diagnostic assays, particularly those that may be applied in a "trap-side" setting, would facilitate the implementation of a wider range of disease control strategies. Here we evaluate the Dual Path Platform (DPP) VetTB assay, a lateral-flow type test for detecting antibodies to M. bovis antigens (MPB83 and ESAT-6/CFP-10). Both serum and whole blood were evaluated as diagnostic samples. Additionally, two methods were evaluated for interpretation of test results (qualitative interpretation by eye and quantitative measurement using an optical reader). The antibody response to MPB83 detected by the DPP VetTB assay increased significantly following experimental M. bovis infection of badgers, whilst the response to ESAT-6/CFP-10 showed no significant change. In sera from TB-free captive and naturally M. bovis infected wild badgers the MPB83 response exhibited a sensitivity of 55 % by eye and quantitative reader (95 % CI: 40-71 and 38-71, respectively), with slightly lower specificity when read by eye (93 % compared to 98 %; 95 % CI: 85-100 and 90-100, respectively). In whole blood, the DPP VetTB assay MPB83 response exhibited a sensitivity of 65 % (95 % CI: 50-80) when interpreted by eye and 53 % (95 % CI: 36-69) using quantitative values, whilst the specificity was 94 % and 98 % respectively (95 % CI: 88-100 and 90-100). Comparison with contemporaneous diagnostic test results from putatively naturally infected and TB-free badgers demonstrated varying levels of agreement. Using sera from naturally M. bovis infected and TB-free badgers, with post mortem confirmation of disease status, the DPP VetTB assay exhibited a sensitivity of 60 % (95 % CI: 41-77) when interpreted using quantitative values (specificity 95 %; 95 % CI: 76-100), and 67 % (95 % CI: 50-84) when read by eye (specificity 95 %; 95 % CI: 86-100). Further work is required to robustly characterize the DPP VetTB assay's performance in a wider selection of samples, and in the practical and epidemiological contexts in which it may be applied.
牛型结核（bTB）由牛分枝杆菌引起，是一个主要的动物健康问题。在英国和爱尔兰共和国，欧洲獾（Meles meles）已被证明是 M. bovis 感染的储存库，阻碍了家畜中 bTB 的根除。合适的诊断检测方法的可用性，特别是那些可在“陷阱边”设置中应用的方法，将有助于实施更广泛的疾病控制策略。在这里，我们评估了双路径平台（DPP） VetTB 检测，这是一种用于检测针对 M. bovis 抗原（MPB83 和 ESAT-6/CFP-10）的抗体的侧向流动型检测。血清和全血均被评估为诊断样本。此外，还评估了两种方法来解释检测结果（通过肉眼进行定性解释和使用光学读取器进行定量测量）。在实验性 M. bovis 感染獾后，DPP VetTB 检测检测到的针对 MPB83 的抗体反应显著增加，而针对 ESAT-6/CFP-10 的反应没有明显变化。在来自无结核病的圈养和自然感染 M. bovis 的野生獾的血清中，通过肉眼和定量读取器观察到针对 MPB83 的反应的灵敏度分别为 55 %（95 % CI：40-71 和 38-71），而通过肉眼观察时的特异性略低（93 % 对 98 %；95 % CI：85-100 和 90-100）。在全血中，DPP VetTB 检测的 MPB83 反应通过肉眼观察的灵敏度为 65 %（95 % CI：50-80），使用定量值的灵敏度为 53 %（95 % CI：36-69），而特异性分别为 94 %和 98 %（95 % CI：88-100 和 90-100）。与同期疑似自然感染和无结核病的獾的诊断检测结果进行比较，显示出不同程度的一致性。使用来自自然感染 M. bovis 和无结核病的獾的血清，并通过死后确认疾病状态，使用定量值解释时，DPP VetTB 检测的灵敏度为 60 %（95 % CI：41-77）（特异性 95 %；95 % CI：76-100），通过肉眼观察的灵敏度为 67 %（95 % CI：50-84）（特异性 95 %；95 % CI：86-100）。需要进一步的工作来更严格地描述 DPP VetTB 检测在更广泛的样本选择以及可能应用的实际和流行病学背景下的性能。
