Bracht Alexa J, O'Hearn Emily S, Fabian Andrew W, Barrette Roger W, Sayed Abu
United States Department of Agriculture, Animal and Plant Health Inspection Service, Foreign Animal Disease Diagnostic Laboratory, Plum Island Animal Disease Center, Orient, NY, United States of America.
United States Department of Agriculture, Animal and Plant Health Inspection Service, Agriculture Select Agent Services, National Import Export Services, Riverdale, MD, United States of America.
PLoS One. 2016 Jan 12;11(1):e0146211. doi: 10.1371/journal.pone.0146211. eCollection 2016.
Senecavirus A (SV-A), formerly, Seneca Valley virus (SVV), has been detected in swine with vesicular lesions and is thought to be associated with swine idiopathic vesicular disease (SIVD), a vesicular disease syndrome that lacks a defined causative agent. The clinical presentation of SIVD resembles that of other more contagious and economically devastating vesicular diseases, such as foot-and-mouth disease (FMD), swine vesicular disease (SVD), and vesicular stomatitis (VS), that typically require immediate rule out diagnostics to lift restrictions on animal quarantine, movement, and trade. This study presents the development of a sensitive, SYBR Green RT-qPCR assay suitable for detection of SV-A in diagnostic swine specimens. After testing 50 pigs with clinical signs consistent with vesicular disease, 44 (88%) were found to be positive for SV-A by RT-qPCR as compared to none from a negative cohort of 35 animals without vesicular disease, indicating that the assay is able to successfully detect the virus in an endemic population. SV-A RNA was also detectable at a low level in sera from a subset of pigs that presented with (18%) or without (6%) vesicular signs. In 2015, there has been an increase in the occurrence of SV-A in the US, and over 200 specimens submitted to our laboratory for vesicular investigation have tested positive for the virus using this method. SV-A RNA was detectable in all common types of vesicular specimens including swabs and tissue from hoof lesions, oral and snout epithelium, oral swabs, scabs, and internal organ tissues such as liver and lymph node. Genome sequencing analysis from recent virus isolates was performed to confirm target amplicon specificity and was aligned to previous isolates.
A组赛内卡病毒（SV-A），以前称为塞内卡山谷病毒（SVV），已在患有水疱性病变的猪中被检测到，并且被认为与猪特发性水疱病（SIVD）有关，SIVD是一种缺乏明确病原体的水疱病综合征。SIVD的临床表现类似于其他更具传染性且在经济上具有破坏性的水疱病，如口蹄疫（FMD）、猪水疱病（SVD）和水疱性口炎（VS），这些疾病通常需要立即进行排除诊断以解除对动物检疫、移动和贸易的限制。本研究介绍了一种灵敏的SYBR Green RT-qPCR检测方法的开发，该方法适用于在诊断猪样本中检测SV-A。在对50头具有与水疱病一致临床症状的猪进行检测后，通过RT-qPCR发现44头（88%）猪的SV-A呈阳性，而35头无水疱病的阴性猪群中无一例阳性，这表明该检测方法能够在地方性流行群体中成功检测到该病毒。在出现（18%）或未出现（6%）水疱症状的一部分猪的血清中也能检测到低水平的SV-A RNA。2015年，美国SV-A的发病率有所上升，使用该方法对提交到我们实验室进行水疱调查的200多个样本进行检测，结果显示该病毒呈阳性。在所有常见类型的水疱样本中都能检测到SV-A RNA，包括来自蹄部病变的拭子和组织、口腔和口鼻上皮、口腔拭子、痂皮以及肝脏和淋巴结等内部器官组织。对近期病毒分离株进行了基因组测序分析，以确认靶标扩增子的特异性，并与先前的分离株进行比对。
