Departamento Sanidad Animal, Facultad Veterinaria, Universidad Complutense, Madrid 28040, Spain.
Viruses. 2013 Oct 22;5(10):2614-23. doi: 10.3390/v5102614.
The diagnosis of Small Ruminant Lentivirus (SRLV) is based on clinical signs, pathological lesions and laboratory testing. No standard reference test for the diagnosis of maedi visna has been validated up to the present, and it is puzzling that tests which detect antibodies against the virus and tests which detect the proviral genome may render opposite results. The aim of this study was to evaluate the presence in milk throughout a lactation period of specific antibodies by ELISA and of SRLV proviral DNA by a PCR of the highly conserved pol region. A six-month study was conducted with the milk of 28 ewes and 31 goats intensively reared. The percentage of animals with antibodies against SRLV increased throughout the study period. Seroprevalence in sheep was 28% at the beginning of the study and by the end it had increased up to 52.4%. In goats, initial seroprevalence of 5.6% increased to 16%. The percentage of PCR positive ewes was stable throughout the study period. Of the positive sheep, 21.4% were PCR-positive before antibodies could be detected and most of them became PCR-negative shortly after the first detection of antibodies. This might suggest that antibodies have a neutralizing effect. In addition, an equal percentage of sheep were always PCR-negative but either became ELISA-positive or was always ELISA-positive, which might support this hypothesis. On the other hand, the PCR results in goats did not follow any pattern and oscillated between 35.3% and 55.6% depending on the month. Most goats positive by PCR failed to develop antibodies in the 6 months tested. We may conclude that the infection and the antibody response to it follow a different trend in sheep and goats.
小反刍兽疫病毒（SRLV）的诊断基于临床症状、病理病变和实验室检测。迄今为止，尚未验证出针对绵羊肺腺瘤病（Maedi-Visna）的标准参考检测方法，令人困惑的是，检测病毒抗体的检测方法和检测前病毒基因组的检测方法可能会得出相反的结果。本研究旨在通过 ELISA 评估泌乳期内牛奶中特异性抗体的存在情况，并通过高度保守的 pol 区 PCR 检测 SRLV 前病毒 DNA。对 28 只绵羊和 31 只山羊进行了为期六个月的密集养殖试验。研究期间，动物对 SRLV 的抗体比例逐渐增加。绵羊在研究开始时的血清阳性率为 28%，到研究结束时上升至 52.4%。山羊的初始血清阳性率为 5.6%，上升至 16%。研究期间，PCR 阳性绵羊的比例保持稳定。在阳性绵羊中，有 21.4%在可检测到抗体之前即为 PCR 阳性，其中大多数在首次检测到抗体后不久即转为 PCR 阴性。这可能表明抗体具有中和作用。此外，有相同比例的绵羊始终为 PCR 阴性，但要么转为 ELISA 阳性，要么始终为 ELISA 阳性，这可能支持这一假说。另一方面，山羊的 PCR 结果没有任何规律，根据月份在 35.3%到 55.6%之间波动。大多数 PCR 阳性的山羊在 6 个月的检测中未能产生抗体。我们可以得出结论，绵羊和山羊的感染和对其的抗体反应遵循不同的趋势。
