1. MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Faculty of Medicine, Imperial College London, London, UK
2. Division of Digestive Diseases, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
3. Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, Fajara, The Gambia
4. Unité d’Épidémiologie des Maladies Émergentes, Institut Pasteur, Paris, France