1. GlaxoSmithKline Biologicals; B-1330 Rixensart Belgium
2. Department of Zoology; University of Oxford; Oxford OX1 3PS United Kingdom
3. New York NY 10956
4. Wellcome Trust/KEMRI Centre for Geographic Medicine Research, Coast; Kilifi Kenya
5. Nuffield Department of Medicine; University of Oxford, John Radcliffe Hospital, Headington; Oxford OX3 9DU United Kingdom