1. Department of ENT, Faculty of Medicine, Omdurman Islamic University, Khartoum, Sudan
2. Kassala Teaching Hospital, Kassala, Sudan
3. Department of Microbiology, Faculty of Medical Laboratory Sciences, Omdurman Islamic University, Khartoum, Sudan
4. Department of Medicine and HIV Metabolic Clinic,Milton Keynes University Hospital NHS Foundation Trust, Eaglestone,Milton Keynes, Buckinghamshire, United Kingdom