Norwegian Veterinary Institute, P.O. Box 64, 1431 Ås, Norway.
Norwegian Veterinary Institute, P.O. Box 64, 1431 Ås, Norway.
Prev Vet Med. 2022 Nov;208:105765. doi: 10.1016/j.prevetmed.2022.105765. Epub 2022 Sep 22.
Early and accurate diagnosis is fundamental for successful surveillance and control of maedi-visna virus (MVV). MVV was detected in Norway in 2019, almost 14 years after the previous outbreak. Genetic analysis indicates persistence of the virus in the sheep population since 2005. The virus was not detected despite continuous serological surveillance. This emphasises the need for improved surveillance, which relies on an understanding of both diagnostic test performance, sampling strategy and the prevalence of the disease. This study therefore aims to evaluate three commercial ELISA tests for MVV antibodies. We conducted a retrospective study using 615 samples from six flocks diagnosed with MVV in 2019. We ran all samples with the following three tests: ID Screen® MVV/CAEV Indirect (IDvet, Grabels, France), IDEXX MVV/CAEV p28 Ab Verification Test (IDEXX Laboratories, Maine, USA) and Elitest MVV/CAEV (Hyphen Biomed, Neuville-sur-Oise, France), hereinafter referred to as ID Screen, IDEXXp28 and Elitest respectively. Without a perfect reference test, we used Bayesian latent class analysis, including conditional dependence between tests, to estimate diagnostic accuracy and true prevalence in the flocks. Using recommended cut-off values, we found that ID Screen and Elitest had significantly higher sensitivity (Se) estimates (99.3 % [97.4-100.0, 95 % Posterior Credible Interval] and 97.4 % [94.1-99.7 %], respectively) than IDEXXp28 (79.5 % [72.3-86.0 %]), while IDEXXp28 and ID Screen had significantly higher specificity (Sp) estimates than Elitest (99.7 % [99.1-100.0], 99.1 % [98.0-99.8 %] and 93.7 % [91.4-95.7 %], respectively). The estimated true prevalence in the six flocks ranged from a median of 0.8-93.5 %. Combining ID Screen and Elitest in serial interpretation showed the highest median Se and Sp (96.7 % [92.0-99.1] and 100.0 % [99.9-100.0], respectively), as well as the highest median positive predictive value (PPV) for the population with the lowest prevalence. Our study supports the use of ID Screen for screening. Further verification with Elitest in serial interpretation will enhance the PPV.
早期、准确的诊断对于成功监测和控制绵羊肺腺瘤病病毒（Maedi-visna virus，MVV）至关重要。2019 年，挪威检测到 MVV，而上次爆发是在 14 年前。遗传分析表明，自 2005 年以来，该病毒一直在绵羊群体中持续存在。尽管进行了持续的血清学监测，但并未检测到该病毒。这强调了需要改进监测，这依赖于对诊断测试性能、采样策略和疾病流行率的理解。因此，本研究旨在评估三种用于 MVV 抗体的商业 ELISA 检测。我们对 2019 年确诊为 MVV 的六个羊群的 615 个样本进行了回顾性研究。我们使用以下三种检测方法对所有样本进行了检测：ID Screen®MVV/CAEV 间接检测试剂盒（IDvet，Grabels，法国）、IDEXX MVV/CAEV p28 Ab 验证检测试剂盒（IDEXX Laboratories，Maine，美国）和 Elitest MVV/CAEV（Hyphen Biomed，Neuville-sur-Oise，法国），以下简称 ID Screen、IDEXXp28 和 Elitest。由于缺乏完美的参考检测方法，我们使用贝叶斯潜在类别分析，包括检测之间的条件依赖性，来估计羊群中的诊断准确性和真实流行率。使用推荐的截断值，我们发现 ID Screen 和 Elitest 的敏感性（Se）估计值显著更高（99.3%[97.4-100.0，95%后验可信区间]和 97.4%[94.1-99.7%]），而 IDEXXp28 的敏感性则较低（79.5%[72.3-86.0%]），而 IDEXXp28 和 ID Screen 的特异性（Sp）估计值显著高于 Elitest（99.7%[99.1-100.0]、99.1%[98.0-99.8%]和 93.7%[91.4-95.7%]）。六个羊群的估计真实流行率中位数范围为 0.8-93.5%。ID Screen 和 Elitest 串联解读的中位数 Se 和 Sp 最高（96.7%[92.0-99.1]和 100.0%[99.9-100.0]），以及在流行率最低的人群中，阳性预测值（PPV）最高。我们的研究支持使用 ID Screen 进行筛查。在串联解释中进一步使用 Elitest 进行验证，将提高 PPV。
