Consistent detection of bovine papillomavirus in lesions, intact skin and peripheral blood mononuclear cells of horses affected by hoof canker.
Authors: Brandt S, Schoster A, Tober R, Kainzbauer C, Burgstaller J P, Haralambus R, Steinborn R, Hinterhofer C, Stanek C
Journal: Equine veterinary journal
Summary
# Editorial Summary: Bovine Papillomavirus and Equine Hoof Canker Hoof canker remains a frustratingly difficult condition to treat, with the underlying cause largely unknown, but emerging evidence now links it to bovine papillomavirus (BPV) types 1 and 2—the same viruses implicated in equine sarcoid. Researchers used PCR-based molecular techniques to screen canker lesions, surrounding intact skin and peripheral blood mononuclear cells from 25 affected horses, detecting BPV-1 and -2 DNA in nearly all samples (24/24 canker lesions, 12/13 skin samples and 10/11 blood samples). Critically, the viral DNA showed 98% sequence identity to BPV-1, appeared in low copy numbers (≤16 copies per cell in tissue, ≤0.35 per blood cell), and evidence of active viral gene transcription (particularly the E5 oncogene) was detected in several specimens, indicating the virus is not simply present as a bystander but is actively involved in disease pathogenesis. Importantly, negative control horses with no canker or other BPV-related lesions tested negative throughout, strengthening the link to disease. These findings suggest that antivirals and immune modulators warrant investigation as therapeutic options, potentially offering a fresh approach to a condition that has historically resisted conventional treatment modalities.
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Practical Takeaways
- •Hoof canker appears causally linked to BPV-1/-2 infection rather than being coincidental, suggesting antiviral or immune-modulating therapies may improve treatment outcomes
- •The consistent presence of viral DNA in intact skin and circulating immune cells indicates systemic infection, not just local tissue involvement
- •Current conventional therapies target symptoms; understanding viral aetiology opens possibilities for adjunctive antiviral or immunomodulatory treatment protocols
Key Findings
- •BPV-1/-2 DNA detected in 24/24 canker lesions, 12/13 intact skin samples, and 10/11 PBMC isolates using conventional PCR
- •Sequencing confirmed 98% identity to BPV-1 in canker, skin and PBMC samples from affected horses
- •Viral E5 oncogene transcription demonstrated in 2/4 canker tissue and 5/7 PBMC isolates, indicating active viral expression
- •BPV DNA absent in all control samples from 13 horses with no clinical signs of canker or BPV-related disease