[1] USA,MED RES INST INFECT DIS,FREDERICK,MD 21701
[2] YALE UNIV,SCH MED,DEPT EPIDEMIOL & PUBL HLTH,YALE ARBOVIRUS RES UNIT,NEW HAVEN,CT 06510
[3] UNIV OXFORD,SIR WILLIAM DUNN SCH PATHOL,OXFORD OX1 3RE,ENGLAND
[4] MONASH UNIV,SCH MED,DEPT MICROBIOL,CLAYTON,VIC 3168,AUSTRALIA
[5] USA,MED MAT DEV ACTIV,FREDERICK,MD 21701