1. Department of Medicine; Groote Schuur Hospital and University of Cape Town; Cape Town South Africa
2. Medical Diagnostic Center; Yaoundé Cameroon
3. Internal Medicine Unit; Sangmelima Reference Hospital; Sangmelima Cameroon
4. Department of Epidemiology and Public Health; Centre Pasteur of Yaoundé; Member of International Network of the Pasteur Institutes; Yaoundé Cameroon