1 Institute of Tropical Medicine, Universitätsklinikum Tübingen, Tübingen, Germany; Vietnamese German Center for Medical research (VG-CARE), Hanoi, Viet Nam; Faculty of Medicine, Duy Tan University, Da Nang, Viet Nam. Electronic address: velavan@medizin.uni-tuebingen.de.
2 Institute of Tropical Medicine, Universitätsklinikum Tübingen, Tübingen, Germany; Vietnamese German Center for Medical research (VG-CARE), Hanoi, Viet Nam; Faculty of Medicine, Duy Tan University, Da Nang, Viet Nam.