1. Institute of Medical Microbiology and Hygiene, Saarland University, Kirrberger Straße, Building 43, 66421 Homburg, Germany
2. Institute of Pneumology at the University of Cologne, Bethanien Hospital, Clinic for Pneumology and Allergology, Centre of Sleep Medicine and Respiratory Care, Aufderhöher Straße 169, 42699 Solingen, Germany
3. Swiss Tropical and Public Health Institute, P.O. Box, CH-4002 Basel, Switzerland
4. University of Basel, P.O. Box, CH-4003 Basel, Switzerland