1. Department of Infectious Diseases, Umeå University, SE-90187 Umeå, Sweden.
2. Section for Zoonotic Ecology and Epidemiology, Department of Biology and Environmental Science, University of Kalmar, SE-39182 Kalmar, Sweden.
3. Department of Virology, Erasmus Medical Center, Rotterdam, Netherlands.
4. Smedby Health Center, Kalmar County Council, SE-39471 Kalmar, Sweden.
5. Division of Virology, Department of Molecular and Clinical Medicine (IMK) Faculty of Health Sciences, Linköping University, SE-581 85 Linköping, Sweden.