1. Department of Virology, Medicum, Faculty of Medicine, University of Helsinki, Helsinki, Finland
2. Department of Virology and Immunology, Helsinki University Central Hospital Laboratory (HUSLAB), Helsinki, Finland
3. Honkaharju hospital, South Karelia Social and Health Care District, Imatra, Finland
4. Department of Veterinary Biosciences, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland