1. Department of Microbiological Surveillance and Research, Statens Serum Institut, Copenhagen, Denmark
2. Department of Epidemiology, Statens Serum Institut, Copenhagen, Denmark
3. Regional Veterinary and Food Control Authority East, Ringsted, Denmark
4. Department of Virology, Statens Serum Institut, Copenhagen, Denmark
5. National Food Institute, Technical University, Copenhagen, Denmark
6. Danish Veterinary and Food Administration, Copenhagen, Denmark
7. Department of Microbiological Diagnostics, Statens Serum Institut, Copenhagen, Denmark