Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga, Portugal.
PLoS One. 2010 Sep 10;5(9):e12663. doi: 10.1371/journal.pone.0012663.
To obtain robust epidemiological information regarding tuberculosis (TB) in wildlife species, appropriate diagnostic methods need to be used. Wild boar (Sus scrofa) recently emerged as a major maintenance host for TB in some European countries. Nevertheless, no data is available to evaluate TB post-mortem diagnostic methods in hunter-harvested wild boar.
METHODOLOGY/PRINCIPAL FINDINGS: Six different diagnostic methods for TB were evaluated in parallel in 167 hunter-harvested wild boar. Compared to bacteriological culture, estimates of sensitivity of histopathology was 77.8%, gross pathology 72.2%, PCR for the MPB70 gene 66.7%, detection of acid-fast bacilli (AFB) in tissue contact smears 55.6% and in histopathology slides 16.7% (estimated specificity was 96.7%, 100%, 100%, 94.4% and 100%, respectively). Combining gross pathology with stained smears in parallel increased estimated sensitivity to 94.4% (94.4% specificity). Four probable bacteriological culture false-negative animals were identified by Discriminant Function Analysis. Recalculating the parameters considering these animals as infected generated estimated values for sensitivity of bacteriology and histopathology of 81.8%, gross pathology 72.7%, PCR for the MPB70 gene 63.6%, detection of AFB in tissue contact smears 54.5% and in histopathology slides 13.6% (estimated specificity was 100% for gross pathology, PCR, bacteriology and detection of AFB in histopathology slides, 96.7% for histopathology and 94.4% for stained smears).
CONCLUSIONS/SIGNIFICANCE: These results show that surveys for TB in wild boar based exclusively on gross pathology considerably underestimate prevalence, while combination of tests in parallel much improves sensitivity and negative predictive values. This finding should thus be considered when planning future surveys and game meat inspection schemes. Although bacteriological culture is the reference test for TB diagnosis, it can generate false-negative results and this should be considered when interpreting data.
为了获得有关野生动物结核病（TB）的可靠流行病学信息，需要使用适当的诊断方法。野猪（Sus scrofa）最近在一些欧洲国家成为结核病的主要维持宿主。然而，目前尚无数据可用于评估在狩猎采集的野猪中进行结核病死后诊断的方法。
方法/主要发现：在 167 只狩猎采集的野猪中，六种不同的 TB 诊断方法并行评估。与细菌培养相比，组织病理学的估计敏感性为 77.8%，大体病理学为 72.2%，MPB70 基因 PCR 为 66.7%，组织接触涂片检测抗酸杆菌（AFB）为 55.6%，组织病理学切片为 16.7%（估计特异性分别为 96.7%、100%、100%、94.4%和 100%）。同时并行进行大体病理学与染色涂片检查，可将估计的敏感性提高到 94.4%（特异性为 94.4%）。通过判别函数分析确定了 4 个可能的细菌培养假阴性动物。重新计算考虑这些动物为感染的参数后，细菌学和组织病理学的估计敏感性分别为 81.8%、大体病理学为 72.7%、MPB70 基因 PCR 为 63.6%、组织接触涂片检测 AFB 为 54.5%，组织病理学切片为 13.6%（大体病理学、PCR、细菌学和组织病理学切片中 AFB 的检测的估计特异性均为 100%，组织病理学为 96.7%，染色涂片为 94.4%）。
结论/意义：这些结果表明，仅基于大体病理学的野猪结核病调查会大大低估患病率，而同时并行进行测试则大大提高了敏感性和阴性预测值。因此，在规划未来的调查和野味检查计划时，应考虑到这一发现。虽然细菌培养是结核病诊断的参考测试，但它可能会产生假阴性结果，在解释数据时应考虑到这一点。
