1. General Hospital Voorkempen/Emmaus group , Malle B-2390 , Belgium
2. Department of General Internal Medicine, Infectious Diseases and Tropical Medicine, Antwerp University Hospital (UZA), University of Antwerp , Edegem B-2650 , Belgium
3. Institute of Tropical Medicine , Antwerp 2000 , Belgium
4. Department of Critical Care Medicine, Antwerp University Hospital (UZA), University of Antwerp , Edegem B-2650 , Belgium