Detection of a Novel Sapelovirus in Central Nervous Tissue of Pigs with Polioencephalomyelitis in the U.S.

Paulo H.E. Arruda, Bailey L. Arruda, Jerome Nietfeld, Fabio Vannucci, Talita Resende, Albert Rovira, Paul Sundberg,

Kent J. Schwartz, Ben M. Hause

History• 3,000 finishing swine operation• 11-week-old pigs

– All affected animals originated from a single nursery and were placed in two different finishers at 9 weeks-of-age

• Atypical neurologic disease • Morbidity of 20% • Case fatality rate of 30%

Clinical Signs

• Inappetence, compromised ambulation, ataxia, incoordination, mental dullness, paresis, paralysis and decreased response to environmental stimuli

• http://www.swinehealth.org/sapelovirus/

Submission

• First case – brain, lung and lymph node• Second case – brain, heart, lung, kidney, liver,

spleen, lymph node and spinal cord (3 animals were sampled)

• Tests were performed individually

Diagnostic Results

• No significant bacteria was isolated• PCR negative for Enterovirus and Teschovirus• PRRS*, pseudorabies, porcine pestivirus and

circovirus PCR negative• Immunohistochemistry for PRRSV, PCV2 and

Listeria - negative• Sapelovirus detected by PCR

Additional Diagnostics

Next-Generation Sequencing

1. Confirmation of Sapelovirus PCR results

• Genome sequence of the virus2. Identification of other potential

known pathogens3. Potential discovery of a novel

pathogen

Sapelovirus A strain KS05151 (AIE77643)

Sapelovirus A strain KS04105 (AIE77642)

Sapelovirus A strain csh (AEK31168)

Sapelovirus A strain YC2011 (AFR77081)

Sapelovirus A strain JD2011 (AHA61456)

Sapelovirus A strain QT2013 (AHY20040)

Sapelovirus A strain KS055217 (AIE77644)

Sapelovirus A strain USA/IA33375/2015 (KX574284)

Sapelovirus A strain ISU-SHIC (KX810827)

Sapelovirus A strain V13 (AF406813)

Sapelovirus B strain SV2-2383 (AY064708)

Avian Sapelovirus strain TW90A (AY563023)

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87

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The VP1 amino acid sequence of members of the genus Sapelovirus were aligned by ClustalW and phylogeny was inferred by Maximum Likelihood analysis with using the best fitting LG+G substitution model with branching strength evaluated by 1,000 bootstrap replicates.

Protein Length (a.a.)

Identity to other Porcine Sapeloviruses

(%)L 84 94.1-97.6

VP4 53 88.7-96.2VP2 238 92.4-95.4VP3 234 86.3-91.5VP1 285 84.6-87.02A 226 86.7-96.52B 105 97.1-1002C 332 92.8-94.63A 100 89.0-90.03B 22 86.4-95.53C 182 96.7-98.93D 462 94.8-98.3

Predicted proteins encoded by Sapelovirus A strain ISU-SHIC and their identity to other Sapelovirus A strains.

PSV in situ hybridization. A. PSV mRNA encoding VP1 protein was demonstrated predominantly in the nerve roots of the spinal cords of affected animals (presumably Schwann cells). B. Neuron with intracytoplasmic positive staining. Figure on right corner shows a higher magnification of cell with positive staining. Hybridization signal: red. Counterstaining: Mayer's Hematoxylin.

Conclusions and Future Studies

• Novel sapelovirus (genetically divergent) was the only pathogen detected in association with a unique clinical presentation and severe polioencephalomyelitis

• Virus was demonstrated within lesions by in situhybridization

• Neurologic disease has not been reported to be associated with sapelovirus from other animal species in the US

Conclusion and Future Studies• Virus isolation in cell culture• Development of an animal model and reproduction of

disease– Pathogenesis– Virus distribution

• Other potential clinical signs (subclinical, respiratory or enteric disease, immunosuppression, reproductive)

• Prevalence/ecology/epidemiology• Genetic diversity of viruses circulating in the US• Prevention/treatment

Thanks

Thank youField veterinarian

• “Listen to your patient, he is telling you the diagnosis” William Osler