1. Clinical Infectious Diseases Research Initiative, Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, Observatory 7925, South Africa
2. Division of Mycobacterial Research, MRC National Institute for Medical Research, London NW7 1AA, UK
3. Department of Environmental and Occupational Health and Center for Global Public Health, School of Public Health, University of Medicine and Dentistry New Jersey, 683 Hoes Lane West, Piscataway, NJ 08854, USA
4. Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge CB2 0SP, UK