Molluscum contagiosum in two donkeys
- R. Fox, BVetMed, DipECVP, MRCVS1,
- A. Thiemann, MA, Vet MB, Cert EP, MSc, MRCVS2,
- D. Everest3,
- F. Steinbach, PhD3,
- A. Dastjerdi, PhD3 and
- C. Finnegan, PhD3
- 1Abbey Veterinary Services, 89 Queen Street, Newton Abbot, Devon, TQ122BG, UK
- 2The Donkey Sanctuary Sidmouth, Devon, EX10 0NU, UK
- 3Science Division, Animal Health and Veterinary Laboratories Agency – Weybridge, Woodham Lane, New Haw, Addlestone, Surrey, KT15 3NB, UK
- E-mail for correspondence:
MOLLUSCUM contagiosum (MC) is a common skin infection in man and mainly seen in children, caused by the molluscum contagiosum virus (MCV). The typical pox virus particle morphology and genomic organisation of MCV led to its classification as a member of the family Poxviridae, subfamily Chordopoxvirinae, where it is the sole member of the genus Molluscipoxvirus (King and others 2011). MCV exists as two genetic subtypes, MCV1 and MCV2, each with several variants (Trama and others 2007) that have a similar clinical presentation in human beings. Lesions in human beings and animals are generally multifocal and are characterised by small, waxy, firm papules occurring principally on the face, trunk and in the genital region but can also be found in the oral cavity (Thompson and others 1998, Scott and Miller 2010).
MC has been observed in other species including chickens, sparrows, pigeons, chimpanzees, kangaroos, dogs and horses (Ginn and others 2007). Equine MCV is thought to be identical to, or closely related to, human MCV. MCV has never been experimentally transmitted between animals (Mitchell 1953, Postlethwaite 1970); attempts to grow MCV in culture have failed. This property differentiates the virus from the orthopoxvirus of Uasin Gishu (UG) caused by Uasin Gishu disease virus (UGDV). UGDV produces histologically and clinically similar lesions to MCV but the virus can be grown in culture (Scott and Miller 2010). UGDV is antigenically similar to cowpox and vaccinia viruses (Scott and Miller 2010). Very little is known about its exact modality of transmission, with fomites and direct prolonged contact often quoted (Scott and Miller 2010). There is also very limited evidence of transmission between horses and man. Similarly, there is only speculation about the transmission between horses and man.
In horses, MC is a self-limiting cutaneous infection with multiple small papules arising …