Dvorak Cheryl M T, Akkutay-Yoldar Zeynep, Stone Suzanne R, Tousignant Steven J P, Vannucci Fabio A, Murtaugh Michael P
Department of Veterinary and Biomedical Sciences, University of Minnesota, 1971 Commonwealth Ave, St. Paul, MN, 55108, USA.
Department of Virology, Ankara University, Faculty of Veterinary Medicine, Diskapi, 06110, Ankara, Turkey.
BMC Vet Res. 2017 Feb 15;13(1):50. doi: 10.1186/s12917-017-0967-x.
Senecavirus A (SVA), a member of the family Picornaviridae, genus Senecavirus, is a recently identified single-stranded RNA virus closely related to members of the Cardiovirus genus. SVA was originally identified as a cell culture contaminant and was not associated with disease until 2007 when it was first observed in pigs with Idiopathic Vesicular Disease (IVD). Vesicular disease is sporadically observed in swine, is not debilitating, but is significant due to its resemblance to foreign animal diseases, such as foot-and-mouth disease (FMD), whose presence would be economically devastating to the United States. IVD disrupts swine production until foreign animal diseases can be ruled out. Identification and characterization of SVA as a cause of IVD will help to quickly rule out infection by foreign animal diseases.
We have developed and characterized an indirect ELISA assay to specifically identify serum antibodies to SVA. Viral protein 1, 2 and 3 (VP1, VP2, VP3) were expressed, isolated, and purified from E. coli and used to coat plates for an indirect ELISA. Sera from pigs with and without IVD symptoms as well as a time course following animals from an infected farm, were analyzed to determine the antibody responses to VP1, VP2, and VP3.
Antibody responses to VP2 were higher than VP1 and VP3 and showed high affinity binding on an avidity ELISA. ROC analysis of the SVA VP2 ELISA showed a sensitivity of 94.2% and a specificity of 89.7%. Compared to IFA, the quantitative ELISA showed an 89% agreement in negative samples and positive samples from 4-60 days after appearance of clinical signs. Immune sera positive for FMDV, encephalomyocarditis virus, and porcine epidemic diarrhea virus antibodies did not cross-react.
A simple ELISA based on detection of antibodies to SVA VP2 will help to differentially diagnose IVD due to SVA and rule out the presence of economically devastating foreign animal diseases.
A 型赛尼卡病毒（SVA）是小核糖核酸病毒科赛尼卡病毒属的成员，是一种最近鉴定出的单链 RNA 病毒，与心病毒属的成员密切相关。SVA 最初被鉴定为细胞培养污染物，直到 2007 年首次在患有特发性水疱病（IVD）的猪中观察到，才与疾病相关联。水疱病在猪中偶尔出现，不会使猪衰弱，但因其与外来动物疾病（如口蹄疫（FMD））相似而具有重要意义，口蹄疫的出现将对美国造成经济破坏。在排除外来动物疾病之前，IVD 会扰乱猪的生产。将 SVA 鉴定并表征为 IVD 的病因将有助于快速排除外来动物疾病的感染。
我们开发并表征了一种间接 ELISA 检测方法，以特异性鉴定针对 SVA 的血清抗体。病毒蛋白 1、2 和 3（VP1、VP2、VP3）从大肠杆菌中表达、分离和纯化，并用于包被酶标板以进行间接 ELISA。分析有和没有 IVD 症状的猪的血清以及来自感染农场的动物的时间进程，以确定对 VP1、VP2 和 VP3 的抗体反应。
对 VP2 的抗体反应高于 VP1 和 VP3，并且在亲和力 ELISA 上显示出高亲和力结合。SVA VP2 ELISA 的 ROC 分析显示敏感性为 94.2%，特异性为 89.7%。与间接免疫荧光法（IFA）相比，定量 ELISA 在临床症状出现后 4 - 60 天的阴性样本和阳性样本中显示出 89%的一致性。口蹄疫病毒、脑心肌炎病毒和猪流行性腹泻病毒抗体阳性的免疫血清没有交叉反应。
基于检测针对 SVA VP2 的抗体的简单 ELISA 将有助于鉴别诊断由 SVA 引起的 IVD，并排除经济上具有破坏性的外来动物疾病的存在。
