1. Department of Internal Medicine, Gastroenterology and Hepatology Unit, Catholic University of Health and Allied Sciences, P.O. Box 1464, Bugando, Mwanza, Tanzania
2. Tropenmedizin, Missionsärztliche Klinik, Salvatorstr. 7, 97074 Würzburg, Germany
3. Medical Microbiology, Goettingen, Germany
4. Medical Mission Institute, Hermann Schell Str. 7, 97074 Würzburg, Germany
5. Department of Microbiology and Immunology, Catholic University of Health and Allied Sciences, P.O. Box 1464, Bugando, Mwanza, Tanzania