A. R. Hollis and M. Starkey Animal Health Trust, Lanwades Park, Kentford, Newmarket, Suffolk CB8 7UU, UK. Email: anna.hollis@aht.org.uk Background: Sarcoids are common in the horse, but their pathogenesis remains poorly understood. The role of bovine papillomavirus (BPV) remains controversial, partly because BPV is found in both sarcoids and normal skin. While viral load has been shown to vary between sarcoid clinical types, no attempt has been made to investigate whether there is an association between BPV load and sarcoid development.