[1] WELLCOME RES LABS,BECKENHAM BR3 3BS,KENT,ENGLAND
[2] ROYAL VICTORIA INFIRM,NEWCASTLE TYNE NE1 4LP,TYNE & WEAR,ENGLAND
[3] LAB NATL BACTERIOL,STOCKHOLM,SWEDEN
[4] UNIV COLORADO,MED CTR,DENVER,CO 80202
[5] UNIV BRITISH COLUMBIA,VANCOUVER V6T 1W5,BC,CANADA
[6] ORGANON SCI DEV GRP,DEV SCI GRP,OSS,NETHERLANDS
[7] ORG MONDIALE SANTE,DIV MALADIES TRANSMISSIBLES,GENEVE,SWITZERLAND
[8] NUFFIELD INST COMPARAT MED,LONDON,ENGLAND