Detection of a novel sapelovirus in central nervous tissue of pigs with polioencephalomyelitis in the USA.
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.
Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA, USA.
P H E
http://orcid.org/0000-0001-5145-8431
PH
Arruda
Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA, USA.
B L
BL
Arruda
Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA, USA.
K J
KJ
Schwartz
University of Minnesota Diagnostic Laboratory, University of Minnesota, St. Paul, MN, USA.
F
F
Vannucci
University of Minnesota Diagnostic Laboratory, University of Minnesota, St. Paul, MN, USA.
T
T
Resende
University of Minnesota Diagnostic Laboratory, University of Minnesota, St. Paul, MN, USA.
A
A
Rovira
Swine Health Information Center, Perry, IA, USA.
P
P
Sundberg
Department of Diagnostic Medicine and Pathobiology, Kansas State University, Manhattan, KS, USA.
J
J
Nietfeld
Department of Diagnostic Medicine and Pathobiology, Kansas State University, Manhattan, KS, USA.
B M
BM
Hause
D000818:Animals; D018173:Circoviridae Infections / Q000453:epidemiology*; D004196:Disease Outbreaks; D004682:Encephalomyelitis, Enzootic Porcine / Q000821:virology*; D004769:Enterovirus Infections / Q000662:veterinary* / Q000821:virology; D004771:Enteroviruses, Porcine / Q000302:isolation & purification; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D009417:Nerve Tissue / Q000821:virology; D010849:Picornaviridae / Q000235:genetics / Q000302:isolation & purification*; D010850:Picornaviridae Infections / Q000662:veterinary*; D016133:Polymerase Chain Reaction; D012328:RNA Viruses; D013552:Swine; D013553:Swine Diseases / Q000453:epidemiology / Q000821:virology*; D014481:United States / Q000453:epidemiology
neurologic disease; polioencephalomyelitis; sapelovirus; swine