1. Division of Gastroenterology and Hepatology
2. Department of Infectious Diseases; Shandong Provincial Hospital affiliated with Shandong University; Jinan Shandong China
3. Division of Epidemiology, Mayo Clinic; Rochester MN
4. Department of Medicine; Faculty of Medicine; Chulalongkorn University and King Chulalongkorn Memorial Hospital; Thai Red Cross Society Bangkok Thailand