1. Travel Clinic, Department of Ambulatory Care and Community Medicine, University Hospital, 44, Rue du Bugnon, CH-1011 Lausanne, Switzerland
2. Division of Infectious Diseases, University Hospital, 46, Rue du Bugnon, CH-1011 Lausanne, Switzerland
3. Swiss Tropical and Public Health Institute, Socinstrasse 57, CH-4002 Basel, Switzerland