1. Department of Infectious Diseases, Bern University Hospital, University of Bern, Bern, Switzerland
2. Division of Gastroenterology and Hepatology, Hôpital Principal, Dakar, Senegal
3. Department of Infectious Diseases, Hôpital Fann, Dakar, Senegal
4. Institute of Social and Preventive Medicine, University of Bern, Bern, Switzerland