1 Cambodia-Oxford Medical Research Unit, Siem Reap, Cambodia.
2 Cambodia-Oxford Medical Research Unit, Siem Reap, Cambodia; Angkor Hospital for Children, Siem Reap, Cambodia.
3 Angkor Hospital for Children, Siem Reap, Cambodia.
4 Cambodia-Oxford Medical Research Unit, Siem Reap, Cambodia; Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK.