INTERNAL MEDICINE
David J. Knapp, M.D.
Dr. David Knapp is a Primary Care Physician and specializes in Internal Medicine. He became interested in medicine while serving as a medic in the U.S. Airforce during the Vietnam era. He became a Registered Nurse and later a Physician Assistant. In 1988 he completed his medical training at the University of Connecticut. Dr. Knapp served as an internist in the U.S. Army from 1991 through 1996 as a Lieutenant Colonel during Desert Storm and Joint Endeavor. He established his practice with Cochise Health Alliance Medical Group, PC (CHAMG) here in Sierra Vista in 1995. In 2005, Dr. Knapp separated his practice from CHAMG and established Sierra Vista Internal Medicine, PLLC as the sole managing member. Dr. Knapp was instrumental in developing the Medical Education Program and Residency Program for Sierra Vista Regional Health Center where he serves as Administrative Director of Medical Education, Preceptor and Continuity Clinic Resident Supervisor. Dr. Knapp has also served as the Medical Director of Hospice since November 1, 2010. Dr. Knapp is married and has four sons. He has more than 34 years of medical experience and has a special interest in geriatric and hospice medicine.
Thomas A. Harris, P.A.-C is a primary care physician assistant. Mr. Harris has been certified since 1996 by the National Commission on Certification of Physician Assistants. Mr. Harris has practiced in the areas of emergency medicine and family medicine. He first became interested in medicine as a Boy Scout earning his First Aid Merit Badge while growing up in Binghamton, New York. He later had an opportunity to further his practical skills in medicine on the family farm, while helping his dad care for a registered Angus herd and a registered Hampshire Downs flock of sheep. In 1976 Mr. Harris joined the U.S. Navy where he became a hospital corpsman and later a Chief Hospital Corpsman. His naval career led him to the Naval Regional Medical Center in San Diego, California where he worked as a Ward Corpsman and a Urology Technician. There he attended Basic Hospital Corp School, Urology Technician School and Independent Duty School. In 1981 Mr. Harris was selected to attend the Naval Undersea Medicine Institute in New London, Connecticut, where he completed Basic Submarine School and the Surface Nuclear Medicine Program. He was then assigned to the USS Nimitz CVN-68 as their Nuclear Medicine Program Administrator. In 1984 he resigned from active naval service and returned to civilian life to earn his Bachelors of Science degree in Allied Health from the George Washington University School of Medicine. In 1985 Mr. Harris joined the U.S. Naval Reserves with his final duty station being Fleet Hospital 15 in Saudi Arabia during Operation Desert Storm. In 1996 Mr. Harris earned his Bachelor of Science degree in Physician Assistant (PA)(Magna Cum Laude) from King's College in Wilkes-Barre, Pennsylvania. Following graduation from PA school, Mr. Harris joined the Emergency Medicine Group in Lebanon, Pennsylvania. In 1997 Mr. Harris re-located to Sierra Vista, Arizona where he joined Cochise Health Alliance Medical Group (CHAMG) in Dr. Marc Kaplan's family practice. In the fall of 2013 Mr. Harris joined Sierra Vista Internal Medicine to assist Dr. David Knapp in the care of his internal medicine patients. Mr. Harris brings more than 30 years of medical experience to the practice. Mr. Harris enjoys hiking, gardening and travel in his leisure time.