1. Division of Gastroenterology, Department of Medicine, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand
2. Department of Biochemistry, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand
3. Department of Microbiology, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand
4. Department of Pathology, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand
5. Department of Pediatrics, Center of Excellence in Clinical Virology, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand