1. Secretariat of the Scientific Committee, Administration of Control Policy, Federal Agency for the Safety of the Food Chain, B-1000 Brussels
2. Department of Animal Health, Institute of Tropical Medicine, B-2000 Antwerp
3. Section of Pathology, Department of Biocontrol, Veterinary and Agrochemical Research Centre, B-1180 Uccle
4. Department of Infectious and Parasitic Diseases, Virology, Epidemiology, and Viral Diseases, Faculty of Veterinary Medicine, University of Liège, B-4000 Liège, Belgium