1. Department of Infectious Diseases, Robert Koch-Institute, Berlin, Germany
2. Consultant Laboratory for Noroviruses, Robert Koch-Institute, Berlin, Germany
3. Department for Infectious Disease Epidemiology, Robert Koch-Institute, Berlin, Germany
4. Institute of Virology, University of Bonn Medical Centre, Bonn, Germany
5. Institute of Medical Virology, Charité University Medicine, Berlin, and Labor Berlin, Charité-Vivantes GmbH, Berlin, Germany
6. Institute of Medical Microbiology, Göttingen, Germany