A Doctor of Medicine and Doctor of Philosophy with more than 50 years of experience, this physician specializes in infectious diseases, internal medicine, diagnostic virology, and experimental pathology (virology). His clinical and research expertise includes viral infections, cytomegalovirus (CMV), herpesvirus infections, influenza, HIV/AIDS-related infections, transplant-associated infections, antiviral resistance, clinical microbiology, laboratory diagnostics, and diagnostic virology. He also has prior expert witness experience.

His professional background includes service as Professor in Residence in Laboratory Medicine and Medicine, Professor Emeritus, Consultant in Infectious Diseases, Associate Chief of Medicine with responsibility for Infectious Diseases, Director of the Clinical Virology Laboratory, and Director of Clinical Virology Research at the University of California, San Francisco and UCSF Medical Center at Mount Zion. His work has encompassed infectious disease consultation, internal medicine, supervision of diagnostic virology services, development and interpretation of laboratory testing, clinical virology research, and oversight of the infectious disease service and clinical virology laboratory operations.

In addition to his clinical practice, he has authored and edited numerous peer-reviewed publications, textbooks, book chapters, and clinical references addressing infectious diseases, clinical virology, cytomegalovirus, antiviral therapy, HIV-related infections, laboratory medicine, and diagnostic microbiology. He has also served on editorial boards and reviewed manuscripts for medical and scientific journals, directed infectious disease and clinical microbiology fellowship training, taught laboratory medicine residents and infectious disease fellows, participated in national guideline development, and delivered invited presentations internationally on infectious diseases, virology, antiviral resistance, and diagnostic testing. His qualifications are further supported by a Doctor of Medicine degree, a Doctor of Philosophy in Experimental Pathology (Virology), board certification in Internal Medicine, Infectious Disease, and Medical Microbiology, and fellowship status in the American College of Physicians and the American Academy of Microbiology, along with memberships in numerous professional organizations related to infectious diseases, microbiology, and clinical virology.