1. Department of Clinical Veterinary Medicine; University of Bristol; Langford BS40 5DU
2. Orchard Veterinary Group; Wirral Park Road Glastonbury BA6 9XE
3. University of Glasgow Veterinary School; Bearsden Road Bearsden Glasgow G61 1QH
4. Ecology and Epidemiology Group; Department of Biological Sciences; University of Warwick; Coventry CV47AL