1. Department of Gastroenterology, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, P.R. China
2. Department of Infectious Diseases, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P.R. China
3. Department of Gastroenterology, The Affiliated Hospital of Guizhou Medical University, Guiyang, P.R. China