[1] Mahidol Univ, Fac Trop Med, Bangkok 10400, Thailand
[2] Wellcome Mahidol Univ Oxford, Trop Med Res Programme, Bangkok, Thailand
[3] KEMRI Wellcome Trust Collaborat Res Programme, Nairobi, Kenya
[4] Minist Hlth, Natl Malaria Control Programme, Nairobi, Kenya
[5] Cho Quan Hosp, Ctr Trop Dis, Ho Chi Minh City, Vietnam
[6] Univ Malawi, Coll Med, Zomba, Malawi
[7] Univ Liverpool, Liverpool Sch Trop Med, Liverpool L3 5QA, Merseyside, England
[8] Univ Oxford, Inst Mol Med, Oxford, England
[9] Ctr Dis Control & Prevent, Atlanta, GA USA
[10] Grp Hosp Pitie Salpetriere, F-75634 Paris, France
[11] London Sch Hyg & Trop Med, London WC1, England
[12] Univ Oxford, Dept Zool, Oxford OX1 3PS, England
[13] WHO, CH-1211 Geneva, Switzerland