Equine Hoof Canker: Bovine Papillomavirus Infection Is Not Associated With Impaired Keratinocyte Differentiation.
Authors: Apprich Veronika, Licka Theresia, Freiler Sabrina, Gabriel Cordula
Journal: Veterinary pathology
Summary
# Equine Hoof Canker and Papillomavirus: Separating Association from Causation Whilst koilocytotic changes in hoof canker tissue resemble those seen in papillomavirus infections, researchers at the University of Veterinary Medicine Vienna investigated whether bovine papillomavirus (BPV-1/2) actually drives canker development through impaired keratinocyte differentiation. Using PCR analysis and immunohistochemistry on tissue samples from 18 canker-affected and 6 control horses, the team found that only 5 of 18 canker cases tested positive for BPV DNA, with no correlation between viral presence and the severity of koilocytotic changes, effectively ruling out BPV as a primary aetiological factor. However, the study confirmed that altered expression patterns of adhesion molecules (E-cadherin, β-catenin) and intermediate filaments (keratins 6 and 14) do occur in canker tissue compared to healthy controls, indicating that disrupted keratinocyte differentiation and compromised epidermal barrier function remain central to pathogenesis. For practitioners, this means that whilst BPV detection may occasionally occur in canker cases, it appears coincidental rather than causative—suggesting that management strategies should continue focusing on the underlying failure of normal hoof epithelial maturation rather than pursuing anti-viral interventions as a primary treatment approach.
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Practical Takeaways
- •Hoof canker is not primarily a papillomavirus disease—BPV detection does not explain the characteristic lesions, so antiviral approaches are unlikely to be effective
- •The underlying problem is abnormal skin cell maturation and loss of barrier function in the affected tissue, which should guide therapeutic targets toward restoring normal keratinocyte differentiation
- •Testing for BPV in canker tissue is not diagnostically useful and should not drive treatment decisions
Key Findings
- •BPV-1/2 DNA detected in 5/18 canker-affected horses and 2/6 control horses with no significant association between BPV presence and koilocytotic keratinocytes
- •Altered expression patterns of keratin 6, keratin 14, E-cadherin, and β-catenin were found in canker tissue compared to controls
- •Impaired keratinocyte differentiation and defective epidermal barrier function confirmed as key pathogenic mechanisms in equine hoof canker independent of BPV infection