1. Centre for Preventive Medicine, Animal Health Trust, Lanwades Park, Kentford, Newmarket, Suffolk CB8 7UU, United Kingdom
2. School of Biological Sciences, University of Liverpool, Crown Street, Liverpool L69 7ZB, United Kingdom
3. Department of Pathology and Infectious Diseases, Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield AL9 7TA, United Kingdom
4. Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, United Kingdom
5. Health Protection Agency, 61 Colindale Avenue, London NW9 5EQ, United Kingdom
6. Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, United Kingdom
7. Al Khaledia Equine Hospital, Riyadh, Saudi Arabia