1. CIISA, Faculty of Veterinary Medicine, Universidade de Lisboa, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
2. Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Postbus 80165, 3508 TD Utrecht, Netherlands
3. Institute for Risk Assessment Sciences, Division of Veterinary Public Health, Utrecht University, Postbus 80163, 3508 TD Utrecht, Netherlands