1. Centre for Infectious Disease Control, National Institute for Public Health and the Environment (Rijksinstituut voor Volksgezondheid en Milieu, RIVM), Bilthoven, the Netherlands
2. Jeroen Bosch Hospital, ’s-Hertogenbosch, the Netherlands
3. Animal Health Service, Deventer, the Netherlands
4. Municipal Health Service “Hart voor Brabant”, ’s-Hertogenbosch, the Netherlands
5. Municipal Health Service Brabant-Southeast, Eindhoven, the Netherlands
6. Municipal Health Service South Limburg, Sittard-Geleen, the Netherlands