Ma Xiaohua, Liu Yonghong, Duan Bofang, Gao Hua, Huang Qixin, Chen Cheng, Nie Ming, Zhang Zhenjie, Wu Zhihong, Guo Kui, Hu Zhe, Du Cheng, Wang Xiaojun, Wang Xue-Feng
State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin 150069, China.
College of Veterinary Medicine, Inner Mongolia Agricultural University, Hohhot 010018, China.
Transbound Emerg Dis. 2025 Jul 30;2025:6696495. doi: 10.1155/tbed/6696495. eCollection 2025.
Maedi-visna (MV) and caprine arthritis encephalitis (CAE) are important viral diseases of sheep and goats. The diseases are caused by a group of genetically closely related lentiviruses known as small ruminant lentiviruses (SRLV), and are collectively referred to as SRLV infections. As the majority of sheep and goats infected with SRLV are asymptomatic, the disease is often overlooked. However, SRLV infection can significantly reduce animal productivity and impede animal trade. Currently, SRLV infection is widespread worldwide, but knowledge of its prevalence in China is limited due to a lack of cost-effective testing. In this study, we successfully developed an indirect enzyme-linked immunosorbent assay (iELISA) based on the SRLV capsid protein (CA) (p28) for the specific detection of anti-SRLV antibodies in serum. Using the application of checkerboard titration to optimize the iELISA assay conditions, the cut-off value was determined to be 0.09 by analyzing S/P values of 181 negative sera against SRLV that were confirmed with western blotting (WB). The method showed good reproducibility, with intra- and inter-assay coefficients of variation (CV) values less than 6.60%. A specificity test showed that the iELISA had no serological cross-reaction with six common small ruminant pathogens. Moreover, it was found to be 400-1600 times more sensitive than the available AGID test. The 93 clinical serum samples that tested SRLV-positive using the iELISA were all confirmed as positive using WB, indicating that the method has a low false positive rate. The iELISA was then applied to assess 4786 clinical serum samples from 13 cities in six provinces in China. The results show that the SRLV positivity rate of sera ranged between 0.85% and 40.00%, with the overall seroprevalence of SRLV being 10.64%. Our results indicate that the developed iELISA will serve as a valuable and efficient screening tool for the large-scale preliminary surveillance and monitoring of SRLV infections in both sheep and goats.
梅迪-维斯纳病（MV）和山羊关节炎脑炎（CAE）是绵羊和山羊的重要病毒性疾病。这些疾病由一组基因密切相关的慢病毒引起，称为小反刍兽慢病毒（SRLV），统称为SRLV感染。由于大多数感染SRLV的绵羊和山羊没有症状，这种疾病常常被忽视。然而，SRLV感染会显著降低动物生产力并阻碍动物贸易。目前，SRLV感染在全球广泛存在，但由于缺乏经济有效的检测方法，其在中国的流行情况了解有限。在本研究中，我们成功开发了一种基于SRLV衣壳蛋白（CA）（p28）的间接酶联免疫吸附测定（iELISA），用于特异性检测血清中的抗SRLV抗体。通过棋盘滴定法应用优化iELISA检测条件，通过分析181份经蛋白质印迹法（WB）确认的针对SRLV的阴性血清的S/P值，确定临界值为0.09。该方法具有良好的重复性，批内和批间变异系数（CV）值均小于6.60%。特异性试验表明，iELISA与六种常见的小反刍兽病原体无血清学交叉反应。此外，发现其敏感性比现有的琼脂免疫扩散试验（AGID）高400 - 1600倍。使用iELISA检测为SRLV阳性的93份临床血清样本经WB均确认为阳性，表明该方法假阳性率低。然后将iELISA应用于评估来自中国六个省份13个城市的4786份临床血清样本。结果显示，血清的SRLV阳性率在0.85%至40.00%之间，SRLV总体血清流行率为10.64%。我们的结果表明，所开发的iELISA将成为一种有价值且高效的筛查工具，用于绵羊和山羊SRLV感染的大规模初步监测。
