1 Foodborne and Waterborne Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
2 Department of Gastroenterology, First Affiliated Hospital, China Medical University, Shenyang, Liaoning, China.
3 Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.