1. Department of Internal Medicine, Ziekenhuis Groep Twente, Almelo/Hengelo, the Netherlands
2. Department of Neurology, Ziekenhuis Groep Twente, Almelo/Hengelo, the Netherlands
3. Public Health Service, Twente, the Netherlands
4. Center for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands
5. Laboratory for Medical Microbiology and Public Health, Hengelo, the Netherlands