1. Medicum, University of Helsinki, Helsinki, Finland
2. Department of Internal Medicine, Oulu University Hospital, Oulu, Finland
3. Etelä-Savo Hospital District, Mikkeli, Finland
4. Department of Clinical Microbiology, Infectious Diseases, Umeå University, Umeå, Sweden
5. Department of Clinical Microbiology, Virology, Umeå University, Umeå, Sweden