1 Department of Pathogen Molecular Biology and Department of Clinical Research, London School of Hygiene and Tropical Medicine, London, UK; Médecins Sans Frontières, Delhi, India.
2 Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK.
3 Department of Public Health, Institute of Tropical Medicine, Antwerp 2000, Belgium. Electronic address: mboelaert@itg.be.