[1] Mahosot Hosp, Microbiol Lab, Lao Oxford Mahosot Hosp, Wellcome Trust Res Unit LOMWRU, Viangchan, Laos
[2] Univ Oxford, Churchill Hosp, Nuffield Dept Clin Med, Ctr Trop Med, Oxford, England
[3] Mahidol Univ, Fac Trop Med, Bangkok, Thailand
[4] Salavan Prov Hosp, Salavan, Laos
[5] Univ Hlth Sci, Fac Postgrad Studies, Viangchan, Laos