[1] Ctr Dis Control & Prevent, Div Parasit Dis, Natl Ctr Infect Dis, Atlanta, GA USA
[2] CDC, Ifakara Hlth Res & Dev Ctr, Dar Es Salaam, Tanzania
[3] Ctr Dis Control & Prevent, Div HIV AIDS Prevent, Natl Ctr HIV STD & Tuberculosis Prevent, Atlanta, GA USA
[4] London Sch Hyg & Trop Med, London WC1, England
[5] Rufiji Dist Council Hlth Management Team, Utete, Tanzania