1. University Division of Communicable Diseases, Royal Free Hospital School of Medicine, Rowland Hill Street, London NW3 2QG, UK
2. Department of Radiology, Royal Free Hospital School of Medicine, Rowland Hill Street, London NW3 2QG, UK
3. Kibongoto Regional Tuberculosis Hospital, PO Box 12, Sanya Juu, Tanzania
4. Kilimanjaro Christian Medical Centre, PO Box 3010, Moshi, Tanzania