Institution: | 1. Department of Production and Population Health, Royal Veterinary College, , Hatfield, Hertfordshire, UK;2. Department of Pathology and Pathogen Biology, Royal Veterinary College, , Hatfield, Hertfordshire, UK;3. Department of Veterinary Medicine, University of Cambridge, , UK;4. Department of Epidemiology and Disease Surveillance, Animal Health Trust, , Newmarket, Suffolk, UK |