1. Pathobiology and Population Sciences; The Royal Veterinary College; Hatfield Herts AL9 7TA UK
2. Queen's Veterinary School Hospital, Department of Veterinary Medicine; University of Cambridge; Cambridge CB30ES UK
3. Clinical Sciences and Services; The Royal Veterinary College; Hatfield Herts AL9 7TA UK
4. Royal (Dick) School of Veterinary Sciences; University of Edinburgh; Roslin Midlothian EH25 9RG UK