Dr. Stephen W. Barthold serves as the director of the Center for Comparative Medicine and a professor of pathology with the joint appointment in the UC Davis School of Veterinary Medicine and School of Medicine.

Dr. Barthold is a veterinary pathologist with expertise in experimental pathology of infectious disease, and pathology of laboratory mice. His laboratory is engaged in research on host-agent interactions during the course of persistent infections with Borrelia burgdorferi (the agent of Lyme disease), Bartonella henselae (the agent of cat scratch fever), and enteric Helicobacters. His group utilizes mouse models and a multidisciplinary approach to these complex problems, including molecular biology, microbiology, immunology and pathology.