1. Manson Unit, Médecins Sans Frontières, London, UK; Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
2. Médecins Sans Frontières, Geneva, Switzerland; Centre for Infectious Disease Epidemiology and Research, University of Cape Town, Cape Town, South Africa
3. Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK