Performance of TB immunodiagnostic tests in Eurasian badgers (Meles meles) of different ages and the influence of duration of infection on serological sensitivity
Performance of TB immunodiagnostic tests in Eurasian badgers (Meles meles) of different ages and the influence of duration of infection on serological sensitivity
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DOI：
10.1186/1746-6148-5-42
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发表时间：
2009-11-17
影响因子：
2.6
通讯作者：
Hewinson, R. Glyn
中科院分区：
文献类型：
--
作者：
Chambers, Mark A.;Waterhouse, Sue;Hewinson, R. Glyn
背景：在英国和爱尔兰的部分地区，欧亚獾（Meles Meles）是牛分枝杆菌感染的储存库，也是牛的潜在感染源。活獾的体外诊断试验是控制该物种结核病战略的重要组成部分。人们已经开发了针对獾的免疫测试，尽管人们对动物年龄对测试表现的影响知之甚少。为了解决这个问题，我们评估了獾在动物年龄方面的三种免疫试验的性能：布洛克试验和布洛克tb STAT-PAK (R)血清学试验以及最近开发的干扰素- γ酶免疫测定（IFN γ EIA）。其他地方公布的数据表明，血清阳性与獾中更为进展的结核病形式有关。为了获得进一步的证据，我们使用了来自一个经过充分研究的獾种群的纵向数据来测试布洛克试验的敏感性与结核病感染持续时间之间的关联。结果：两项血清学测试对幼崽和成年犬的敏感性约为54%。当使用一个共同的临界值来定义测试阳性时，幼崽对IFN γ EIA的敏感性（57%）低于成年（85%）。仅从幼崽中获取数据，可以调整IFN γ EIA截止值，将灵敏度提高到71%，而特异性没有损失。作为一般观察，所有测试的特异性在幼崽中更高，尽管只有在布洛克测试的情况下才显着如此。使用逻辑回归分析调整年龄，Brock试验的敏感性在首次培养阳性事件时显著降低（58%），但随着感染的进展增加到bbb80 %。结论：这些数据表明，血清诊断可以作为一种有价值的工具，用于检测更高比例、传播感染可能性最大的獾。獾的年龄类别似乎对血清学测试的表现影响不大。虽然只有少数幼崽的IFN γ EIA数据可用，但在这些个体中测试的敏感性降低表明，在测试幼崽时可能需要更低的临界值。
Background: In parts of Great Britain and Ireland, Eurasian badgers (Meles meles) constitute a reservoir of Mycobacterium bovis infection and a potential source of infection for cattle. In vitro diagnostic tests for live badgers are an important component of strategies to control TB in this species. Immunological tests have been developed for badgers, although little is known about the influence of the age of the animal on test performance. To address this, we evaluated the performance of three immunological tests for badgers with respect to the age of the animal: the Brock Test and BrockTB STAT-PAK (R) serological tests and the recently developed interferon-gamma enzyme immunoassay (IFN gamma EIA). Data published elsewhere suggested that seropositivity was associated with more progressive forms of TB in the badger. To gain further evidence for this, we used longitudinal data from a well-studied population of badgers to test for an association between the sensitivity of the Brock Test and the duration of TB infection.Results: Sensitivity of the two serological tests was approximately 54% for both cubs and adults. Sensitivity of the IFN gamma EIA was lower in cubs (57%) compared with adults (85%) when a common cut-off value was used to define test positivity. Taking data from the cubs alone, the IFN gamma EIA cut-off value could be adjusted to increase the sensitivity to 71% with no loss in specificity. As a general observation, specificity of all tests was higher in cubs, although only significantly so in the case of the Brock Test. Using logistic regression analysis to adjust for age, sensitivity of the Brock Test was significantly lower at first culture positive event (58%), but increased to >80% as infection progressed.Conclusion: These data suggest that serodiagnosis could be a valuable tool for detecting a higher proportion of badgers with the greatest probability of transmitting infection. The age category of the badger appeared to exert little influence on the performance of the serological tests. Although data were only available for the IFN gamma EIA in a small number of cubs, reduced sensitivity of the test in these individuals suggests a lower cut-off may be needed when testing younger animals.