Real-Time Reverse Transcription PCR Assay for Detection of Senecavirus A in Swine Vesicular Diagnostic Specimens.
Authors: Bracht Alexa J, O'Hearn Emily S, Fabian Andrew W, Barrette Roger W, Sayed Abu
Journal: PloS one
Summary
# Editorial Summary: Real-Time RT-PCR Detection of Senecavirus A in Swine Senecavirus A (SV-A) has emerged as a probable aetiological agent in swine idiopathic vesicular disease (SIVD), a condition clinically indistinguishable from notifiable diseases such as foot-and-mouth disease, making rapid, reliable diagnostics essential for disease control and trade management. Bracht and colleagues developed and validated a SYBR Green reverse transcription quantitative PCR assay capable of detecting SV-A RNA across diverse specimen types commonly collected during vesicular disease investigation. Testing on 50 symptomatic pigs yielded 88% positive results (44/50), with zero positives in a negative control group of 35 asymptomatic animals, whilst SV-A RNA was also detected in serum from 18% of affected and 6% of clinically normal pigs, indicating both systemic and localised infection patterns. The assay successfully detected viral nucleic acid in all specimen types submitted for vesicular investigation—including hoof, oral, and snout lesions alongside internal tissues—with genomic sequencing confirming target specificity against contemporary isolates. For equine practitioners encountering potentially vesicular conditions, this work underscores the importance of standardised molecular diagnostics in differential diagnosis and the value of submitting multiple specimen types to maximise detection sensitivity when ruling out high-consequence vesicular pathogens.
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Practical Takeaways
- •This RT-qPCR assay provides a rapid, sensitive diagnostic tool to differentiate SV-A from other economically devastating vesicular diseases (FMD, SVD, VS) to facilitate appropriate quarantine and movement restrictions
- •Veterinarians should consider SV-A in differential diagnosis of swine with vesicular lesions, particularly as prevalence has increased significantly in US herds
- •Multiple specimen types (hoof swabs, oral swabs, tissue samples) can be used for diagnosis, allowing flexibility in sample collection protocols during outbreak investigations
Key Findings
- •RT-qPCR assay detected SV-A in 88% (44/50) of pigs with vesicular disease clinical signs versus 0% (0/35) in negative control animals
- •SV-A RNA was detectable in 18% of pigs with vesicular signs and 6% of pigs without vesicular signs from serum samples
- •Over 200 diagnostic specimens tested positive for SV-A in 2015, indicating increasing prevalence in US swine populations
- •SV-A RNA was successfully detected in all common vesicular specimen types including hoof, oral, snout, and internal organ tissues