[1] Univ London Imperial Coll Sci Technol & Med, Fac Med, Sch Publ Hlth, London Ctr Neglected Trop Dis Res,London Ctr Negl, London W2 1PG, England
[2] Univ London Imperial Coll Sci Technol & Med, Fac Med, Sch Publ Hlth, Dept Infect Dis Epidemiol, London W2 1PG, England
[3] Univ London Imperial Coll Sci Technol & Med, Fac Med, Sch Publ Hlth, Schistosomiasis Control Initiat,Dept Infect Dis E, London W2 1PG, England
[4] Univ London Imperial Coll Sci Technol & Med, Fac Med, Sch Publ Hlth, MRC Ctr Outbreak Anal & Modelling,Dept Infect Dis, London W2 1PG, England