1. College of Medical Sciences, Ahmadu Bello University Teaching Hospital, Shika, Kaduna State
2. Department of Research and Education, Oli Health Magazine Organization, Kigali, Rwanda
3. Faculty of Pure and Applied Sciences, Fourah Bay College, Freetown, Sierra Leone
4. College of Medical Sciences, Ahmadu Bello University, Zaria
5. Department of Research, Medical Research Circle, Bukavu
6. Faculty of Medicine, University of Goma, Goma, Democratic Republic of the Congo
7. Department of Medicine, State Hospital, Ijebu-Ode, Ogun State, Nigeria