1. Department of Infectiology and Hygiene, NRW Centre for Health, Münster, Germany
2. Public Health Department, Soest, Germany
3. Institute for Medical Microbiology and Hygiene, National Consulting Laboratory for Legionella, University of Technology, Dresden, Germany
4. Institute for Hygiene and Public Health, University of Bonn, Bonn, Germany
5. Division Health Protection, Health Promotion, NRW Centre for Health, Münster, Germany