1. Department of clinical Sciences, Faculty of Medicine and Pharmaceutical Sciences, University of Douala, Douala, Cameroon
2. Department of Internal Medicine, Douala Gyneco-Obstetrics and Pediatrics Hospital, Douala, Cameroon
3. Department of Internal Medicine, Douala General Hospital, Douala, Cameroon
4. Department of Internal Medicine, Faculty of Medicine and Pharmaceutical Sciences, University of Dschang, Dschang, Cameroon
5. Department of Internal Medicine, Faculty of Medicine and Biomedical Sciences, University of Yaoundé, Yaoundé, Cameroon