1. Medical Research Council Unit, The Gambia, at the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
2. Department of Microbiology and Immunology, The University of Melbourne at The Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
3. Tropical Epidemiology Group, London School of Hygiene and Tropical Medicine, United Kingdom
4. Microbiological Diagnostic Unit Public Health Laboratory, Department of Microbiology and Immunology, The University of Melbourne at The Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia