title: Consistent detection of bovine papillomavirus in lesions, intact skin and peripheral blood mononuclear cells of horses affected by hoof canker.
abstract: BACKGROUND
  Equine hoof canker is a chronic proliferative pododermatitis of as yet unknown aetiology. Like equine sarcoid disease, canker is a therapy-resistant disorder characterised by hyperkeratosis, acanthosis and a marked tendency to recur.
  
  
  OBJECTIVE
  There is an association of sarcoid-inducing bovine papillomaviruses of types 1 and 2 (BPV-1, BPV-2) with hoof canker disease.
  
  
  METHODS
  Using PCR-based techniques, we assessed canker tissue, intact skin and/or peripheral blood mononuclear cells (PBMCs) of 25 canker-affected horses for the presence of sarcoid-associated BPV-1 and -2.
  
  
  RESULTS
  Conventional PCR revealed BPV-1/-2 DNA in 24/24 canker, 12/13 skin and 10/11 PBMC DNA isolates. Using inverse PCR, full-length BPV episomes were detected in 1/5 canker specimens. Sequencing of viral early and late genes amplified from canker, intact skin and PBMC DNA of 2 cases revealed an overall identity of 98% to BPV-1. Viral DNA loads amounted to ≤16 copies per cell in canker tissue and intact skin, and to ≤0.35 copies per PBMC, as determined by quantitative PCR. Using RT-PCR, the viral major oncogene E5 was shown to be transcribed in 2/4 canker tissue specimens and 5/7 PBMC isolates. Immunocapture PCR from 7 canker and 6 skin extract supernatants revealed capsomere-associated viral DNA in one canker and one skin sample. Hoof tissue, skin and PBMCs collected from 13 individuals with no signs of canker or BPV-related malignancies scored negative throughout the experiments.
  
  
  CONCLUSIONS
  These findings suggest that the observed presence of BPV-1/-2 in canker-affected horses is not coincidental but indicative of an active contribution to hoof canker disease.
  
  
  CONCLUSIONS
  The use of antivirals and/or immune modulators may help improving canker therapy.
authors: Equine Clinic, VetOMICs Core Facility, Veterinary University Vienna, Austria. sabine.brandt@vetmeduni.ac.at
authors: S
authors: S
authors: Brandt
authors: A
authors: A
authors: Schoster
authors: R
authors: R
authors: Tober
authors: C
authors: C
authors: Kainzbauer
authors: J P
authors: JP
authors: Burgstaller
authors: R
authors: R
authors: Haralambus
authors: R
authors: R
authors: Steinborn
authors: C
authors: C
authors: Hinterhofer
authors: C
authors: C
authors: Stanek