Vetnews April 2021: Bovine Papillomaviruses

Introduction

Papillomaviradae are non-enveloped DNA viruses composed of icosahedral capsids. They are epitheliotropic resulting in proliferative lesions termed papilloma (warts) of which there are 2 histological types namely classical papillomas and fibropapillomas (which contain a fibrous core of connective tissue and termed sarcoids). Papilloma viruses gain access to basal epithelial cells through abrasions or where epithelial cells become naturally exposed at mucocutaneous junctions.  Infected cells are stimulated into excessive growth by three viral encoded oncogenes namely E5, E6 and E7.