1. Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University , Bangkok 10400 , Thailand
2. Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, New Richards Building, Old Road Campus , Roosevelt Drive, Oxford, OX3 7LG , UK
3. Oxford University Clinical Research Unit, Hospital for Tropical Diseases , 764 Vo Van Kiet, District 5, Ho Chi Minh City , Vietnam