1. Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR
2. Pediatric Department, Tulane University School of Medicine, New Orleans, LA, USA
3. Pediatric Department, Mahosot Hospital, Vientiane, Lao PDR
4. Nuffield Department of Medicine, Centre for Tropical Medicine, Nuffield Department of Medicine, Churchill Hospital, University of Oxford, UK