Equine Papillomaviruses

Introduction

Equine papillomas are small, warts that occur on the muzzle and in the oral cavity of young horses. They are not to be confused with sarcoids, that are a locally aggressive tumour of the integument and may have a similar appearance.

The virus affects the stratified squamous and/or mucosal epithelium and grows slowly - lesions may take weeks to appear. The viruses in this family are species specific and transfer is usually by direct contact, however, the virus can survive for long periods of time in the environment and can also be spread by fomites. The virus persists even when warts have resolved, giving life long immunity and antibody protection.

Signalment

This virus occurs only in horses. There is no breed or sex predilection, but the virus does usually occur in horses aged 1 - 3 years old.

Clinical Signs

Warts on the muzzle and in the oral cavity of horses. Can prevent eating properly if very severe in the oral cavity.

Diagnosis

Clinical signs and signalment of the horse are all that is required for diagnosis.

Treatment and Control

These papillomas usually resolve spontaneously but can be treated by laser or cryo-freezing if requested or if very large and affecting the animals quality of life.

No valid vaccines are commercially available.

References

Bridger, J and Russell, P (2007) Virology Study Guide, Royal Veterinary College

Knottenbelt, D.C. A Handbook of Equine Medicine for Final Year Students University of Liverpool

Rose, R. J. and Hodgson, D. R. (2000) Manual of Equine Practice (Second Edition) Saunders