1. Division of Gastroenterology and Hepatology, Department of MedicineFaculty of Medicine, University of Malaya Kuala Lumpur Malaysia
2. Faculty of Medicine and Health SciencesUniversity Science Islam Malaysia Kuala Lumpur Malaysia
3. Department of Medical Microbiology, Faculty of MedicineUniversity of Malaya Kuala Lumpur Malaysia
4. Michael E. DeBakey Veterans Health Administration CenterBaylor College of Medicine Houston Texas, USA