1. Department of Veterinary Regulation and International Liaison; Hong Kong Jockey Club; Sha Tin Racecourse Sha Tin NT Hong Kong
2. Centre for Preventive Medicine; Animal Health Trust; Lanwades Park Kentford Newmarket CB8 7UU
3. Department of Veterinary Clinical Services; Hong Kong Jockey Club; Sha Tin Racecourse; Sha Tin NT Hong Kong
4. Epidemiology Group; Faculty of Veterinary Science; University of Liverpool; Leahurst Neston CH64 7TE