[1] Univ London London Sch Hyg & Trop Med, Dept Infect & Trop Med, London WC1E 7HT, England
[2] Natl Inst Med Res, Div Parasitol, London NW7 1AA, England
[3] Nanyang Technol Univ, Sch Biol Sci, Singapore 2263, Singapore
[4] Inst Cochin Genet Mol, INSERM, U567, CNRS UMR 8104,Dept Immunol, F-75014 Paris, France