Arruda P H E, Arruda B L, Schwartz K J, Vannucci F, Resende T, Rovira A, Sundberg P, Nietfeld J, Hause B M
Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA, USA.
University of Minnesota Diagnostic Laboratory, University of Minnesota, St. Paul, MN, USA.
Transbound Emerg Dis. 2017 Apr;64(2):311-315. doi: 10.1111/tbed.12621. Epub 2017 Feb 3.
An approximately 3,000 finishing swine operation in the United States experienced an outbreak of an atypical neurologic disease in 11-weeks-old pigs with an overall morbidity of 20% and case fatality rate of 30%. The clinical onset and progression of signs in affected pigs varied but included inappetence, compromised ambulation, ataxia, incoordination, mental dullness, paresis, paralysis and decreased response to environmental stimuli. Tissues from affected pigs were submitted for diagnostic investigation. Histopathologic examination of the cerebrum, cerebellum and spinal cord revealed severe lymphoplasmacytic and necrotizing polioencephalomyelitis with multifocal areas of gliosis and neuron satellitosis, suggestive of a neurotropic viral infection. Bacterial pathogens were not isolated by culture of neurologic tissue from affected pigs. Samples tested by polymerase chain reaction (PCR) were negative for pseudorabies virus and atypical porcine pestivirus. Immunohistochemistry for porcine reproductive and respiratory syndrome virus, porcine circovirus and Listeria was negative. Porcine sapelovirus (PSV) was identified in spinal cord by a nested PCR used to detect porcine enterovirus, porcine teschovirus and PSV. Next-generation sequencing of brainstem and spinal cord samples identified PSV and the absence of other or novel pathogens. In addition, Sapelovirus A mRNA was detected in neurons and nerve roots of the spinal cord by in situ hybridization. The PSV is genetically novel with an overall 94% amino acid identity and 86% nucleotide identity to a recently reported sapelovirus from Korea. This is the first case report in the United States associating sapelovirus with severe polioencephalomyelitis in pigs.
美国一家存栏约3000头育肥猪的养殖场，11周龄的猪群爆发了一种非典型神经疾病，总体发病率为20%，病死率为30%。患病猪的临床症状出现和发展情况各异，但包括食欲不振、行走能力受损、共济失调、协调障碍、精神迟钝、轻瘫、瘫痪以及对环境刺激的反应减弱。将患病猪的组织送检进行诊断调查。对大脑、小脑和脊髓进行组织病理学检查，发现严重的淋巴细胞浆细胞性坏死性脑脊髓炎，伴有多灶性胶质细胞增生和神经元卫星现象，提示为嗜神经性病毒感染。通过对患病猪神经组织进行培养，未分离出细菌病原体。经聚合酶链反应（PCR）检测的样本，伪狂犬病病毒和非典型猪瘟病毒均为阴性。猪繁殖与呼吸综合征病毒、猪圆环病毒和李斯特菌的免疫组化检测结果均为阴性。通过用于检测猪肠道病毒、猪泰勒病毒和猪萨佩罗病毒的巢式PCR，在脊髓中鉴定出猪萨佩罗病毒（PSV）。对脑干和脊髓样本进行的二代测序确定了PSV的存在，且未发现其他或新型病原体。此外，通过原位杂交在脊髓的神经元和神经根中检测到萨佩罗病毒A mRNA。该PSV在基因上是新的，与最近报道的来自韩国的一种萨佩罗病毒总体氨基酸同一性为94%，核苷酸同一性为86%。这是美国首例将萨佩罗病毒与猪严重脑脊髓炎相关联的病例报告。
