1. INRA UR0346 Animal Epidemiology; VetagroSup; Marcy l'Etoile France
2. INRA UR0346 Animal Epidemiology and Equine Department; VetAgroSup; Marcy L'Etoile France
3. Animal Health Laboratory; UMR1161 Virologie, INRA ANSES ENVA; UPE, ANSES; Maisons-Alfort France
4. National Veterinary Institute; Technical University of Denmark; Frederiksgerg Denmark
5. Central Veterinary Institute; part of Wageningen UR; Lelystad The Netherlands
6. Department of Farm Animal Health; Faculty of Veterinary Medicine; Utrecht University; Utrecht The Netherlands