1. Department of Bacteriology and Food SafetyAnimal and Plant Health Agency (APHA – Weybridge) Addlestone, KT15 3NB UK
2. Department of Epidemiological SciencesAnimal and Plant Health Agency (APHA – Weybridge) Addlestone, KT15 3NB UK
3. Department of Pathology and Infectious Diseases, School of Veterinary Medicine, Faculty of Health and Medical SciencesUniversity of Surrey Guildford, GU2 7AL UK