David Y. Graham, M.D. is physician at the Michael E. DeBakey VA Medical center, and a Professor in the Departments of Medicine and Molecular Virology and Microbiology at Baylor College of Medicine, in Houston, TX,. He received his undergraduate degree from the University of Notre Dame in South Bend, Indiana and his M.D. degree, with honor, from Baylor University College of Medicine in 1966. He is board certified in Medicine and Gastroenterology. Dr. Graham is the author of more than 1000 scientific papers, several books, and 125 chapters in medical text books. He is one of ISI's Highly Cited Researchers in Clinical Medicine. He has trained more than 125 foreign physician-scientists and more than 100 U.S. Gastroenterology fellows. He has patents regarding development of diagnostic tests for Helicobacter pylori infection, the cause of peptic ulcer and gastric cancer, and for vaccine development of Norwalk virus infection, the most common cause of food borne and cruse ship associated diarrhea. His research currently focuses on infectious agents of the gastrointestinal track and include Helicobacter pylori, the cause of peptic ulcers and gastric cancer, rotavirus and Norwalk viruses, and Mycobacterium paratuberculosis a suspected cause of Crohn’s disease.