[1] MAHIDOL UNIV,FAC TROP MED,BANGKOK,THAILAND
[2] SAPPASITPRASONG HOSP,DEPT MED,UBON RATCHATHANI,THAILAND
[3] DERRIFORD HOSP,PUBL HLTH LAB,DERRIFORD,DEVON,ENGLAND
[4] UNIV OXFORD,JOHN RADCLIFFE HOSP,NUFFIELD DEPT CLIN MED,CTR TROP MED,OXFORD,ENGLAND