top of page
Dost Sarpel, MD

Board Certified in Pulmonary Disease and Internal Medicine

Dr. Dost Sarpel completed his Internal Medicine Residency and Infectious Disease Fellowship at the George Washington University Hospital in Washington D.C.  


After finishing his fellowship, Dr. Sarpel worked as consultant for many hospitals throughout the East Bay area in California. During this time he was a key part in managing Infection Control and Antibiotic Stewardship programs at numerous hospitals and long term care facilities.  


He then made the decision to pursue additional training because of his strong interest in viral hepatitis.  He completed a Viral Hepatology Fellowship under the mentorship of Dr. Douglas Dieterich, a world renowned hepatologist, at the Icahn School of Medicine at Mount Sinai.  


Dr. Sarpel has noted expertise in treating patients with HIV, chronic hepatitis C, or chronic hepatitis B as well as patients with co-infection of these viruses, and has given many lectures on these topics.  

doc (1).jpg
Professional Expert Witness Team
Seeking an expert witness that specializes in Infectious Disease, Pulmonary Medicine, or Internal Medicine?

Praxis Infectious Disease is comprised of a team of board-certified infectious disease physicians who provide targeted, timely telehealth patient consultations, and critical support for Infectious Disease Prevention and Antimicrobial Stewardship Programs.

Praxis ID specialists bring the most up-to-date, expert knowledge that is immediately applicable to help support facilities that cannot accommodate full time Infectious Diseases staff. They provide protocols, procedures, and patient management so rural hospitals may benefit from the support of their own Infectious Diseases doctor. With more than 5 years of focused remote support for critical access hospitals, Praxis ID providers have over 20,000 unique patient visits, are certified in Antimicrobial stewardship and infection prevention, and have a proven track record of improving quality of care. 

Litigation Support - A broad spectrum of clinical, theoretical, and organizational experience in Infectious Diseases make Praxis ID a trusted asset for your case. Providing medical case review, thorough reporting, depositions, and trial testimony for both plaintiff and defense.


Who We Are

Dr. Asfour and his team has worked extensively in adult infectious diseases for the past 20 years. He has had more than 35,000 direct patient encounters. He also has experience in reviewing cases for both the plaintiff and defense.

Ramzi Asfour, MD

Board Certified in Infectious Diseases and Internal Medicine

Dr. Asfour is board certified in Infectious Diseases and Internal Medicine. In addition to his work in the US seeing patients, he has worked for the World Health Organization. He is also Assistant Clinical Professor of Medicine at UCSF. He is generally available on short notice and is an efficient worker with a short turn-around time for legal case review. He has extensive experience in treating patients and advising hospitals and skilled nursing facilities in Infection Control (Including outbreak management / COVID-19) and Antimicrobial Stewardship.

Meet The Team

Christina T Hopson, DO

Board Certified Infectious Disease Specialist

Dr. Christina T Hopson, DO, is an Infectious Disease specialist in Livermore, California. She attended and graduated from New York College Of Osteo Medicine Of New York Institute Of Technology in 1994, having over 27 years of diverse experience, especially in Infectious Disease.

Untitled design (3).png
David Joel Witt , MD, FIDSA, CIC

Board Certified in Infectious Diseases, Clinical Genetics, and Pediatrics

Dr. Witt is an Infectious Disease Specialist and the Regional hospital epidemiologist with Kaiser Permanente in Northern California.  He attended medical school at the University of Michigan and residency and fellowship at The Boston City Hospital in Boston, MA.  He has been board certified in Internal Medicine, Infectious Diseases, Emergency Medicine, and certified in Tropical Medicine and Infection Control.  He has been on the faculty of the Schools of Medicine and Nursing at the University of California at San Francisco.

Dr. Witt served as Chair of the Healthcare Associated Infections Advisory Committee for the State of California. With Kaiser Permanente, he chaired the Northern California Regional Infection Prevention Committee and the Clinical Workgroup for National Healthcare Continuity, which addresses Emergency Preparedness for Kaiser Permanente. He works with The MENTOR Initiative, a British NGO dedicated to reducing the burden of vector-borne diseases in humanitarian crises. As Clinical Director for the MENTOR Initiative, he has responded to multiple disasters, including the Indonesian Tsunami, the Tana River floods in Kenya and Somalia, Cyclone Nargis in Myanmar and the earthquake in Haiti.  

Previously, he served as a Technical Auditor for the US State Department, working for the ISTC, an activity of seven countries and the European Union dedicated to non-proliferation of the former Soviet Union’s Nuclear, Chemical and Biologic weapons and their technology.

Untitled design (12).png
Luke Davis  YSPH YSM_edited.png
John Lucian Davis, MD

Board Certified in Pulmonary Disease and Internal Medicine

Dr. Luke Davis is Board Certified in Pulmonary Medicine and in Critical Care Medicine and a practicing intensivist with over two decades of clinical experience in academic, community, and safety net hospitals in California, Connecticut, Hawaii, and Maryland. He is a graduate of Princeton University (A.B., Summa Cum Laude), Vanderbilt University School of Medicine (M.D.), and the University of California San Francisco (M.A.S., Clinical Research), and completed residency training at the Johns Hopkins Hospital and fellowship at the University of California San Francisco. Dr. Davis is an expert in the diagnosis and management of pulmonary infections, including tuberculosis.

bottom of page