[1] Univ London London Sch Hyg & Trop Med, Dept Infect Dis Epidemiol, Keppel St, London WC1E 7HT, England
[2] MRC Unit, Dis Control & Eliminat Theme, Banjul, Gambia
[3] MRC Unit, Clin Serv Dept, Banjul, Gambia
[4] MRC Unit, Vaccinol Theme, Banjul, Gambia
[5] Inst Trop Med, Mycobacteriol Unit, B-2000 Antwerp, Belgium