David H. Walker is Chair of the Department of Pathology and founding Director of the World Health Organization Collaborating Center for Tropical Diseases and the Center for Biodefense and Emerging Infectious Diseases at the University of Texas Medical Branch at Galveston. Born and raised in middle Tennessee, he pursued premedical and liberal arts studies and graduated with a history major from Davidson College in 1965. The combination of wanderlust, experiences during summers in Ecuador, Spain, England, and Boston, and influences of his medical education led to the decision at the end of his third year at Vanderbilt University School of Medicine to pursue a career in tropical infectious diseases via the specialty of pathology. During his residency at the Peter Bent Brigham Hospital and research fellowship at Harvard Medical School (1969-1973), he studied Chagas' disease in the laboratory of Dr. Franz von Lichtenberg and as a research rotation for six months at Gorgas Memorial Laboratory in the Republic of Panama. His development as a scientist was advanced tremendously by two years as a Research Medical Officer in the U.S. Public Health Service under the mentorship of Frederick A. Murphy, D.V.M., Ph.D. at the Centers for Disease Control in Atlanta. There he was engaged in full time research focused on arenaviruses, particularly Lassa virus pathogenesis investigations in the biosafety level-4 laboratory. His initiation of active research in the old glove box facility stimulated further development of the program leading to the CDC's leadership today in the world of investigating hazardous viruses.

Walker was most fortunate to have been offered a faculty position at the University of North Carolina at Chapel Hill in 1975. His chairman, Joe W. Grisham, M.D., enabled him to establish a career in infectious disease pathology and stimulated him to succeed as an independent NIH-funded scientist. In 1987 Walker accepted the Chair in Pathology at UTMB in Galveston and began developing a group of scientists focused on the investigation of infectious diseases. It is one of the premier centers studying arthropod and rodent borne viral infections and rickettsial and ehrlichial diseases anywhere in the world. Since 1997 funding by the Defense Advanced Research Projects Agency enabled pursuit of novel treatment of diseases caused by agents important in both biodefense and tropical public health. In September 2003 a $48 million Regional Center of Excellence in Biodefense and Emerging Infectious Diseases was awarded to Walker by NIH, and two months later the first biosafety level-4 laboratory at a university in the U.S. was opened in his Department.

His academic research career has focused on rickettsial and ehrlichial diseases in which he has expertise in molecular microbiology, immunity, pathology, pathogenesis, clinical pathophysiology, epidemiology, and diagnosis. He had made important contributions to elucidating the protective immune mechanisms against rickettsiae and ehrlichiae, the discovery (Anaplasma phagocytophilum) and characterization (Rickettsia japonica, R. felis) as agents of emerging infectious diseases, description of new diseases (human granulocytotropic anaplasmosis, flea-borne spotted fever), and contributions to the descriptions of the pathology of Lassa fever, Rocky Mountain spotted fever, boutonneuse fever, and human monocytotropic ehrlichiosis. His pioneering utilization of the application of immunohistochemistry to infectious diseases provided diagnostic methods for rickettsioses and the first identification of the target cells of rickettsialpox and scrub-typhus. His development of animal models of spotted fever and typhus rickettsioses and monocytotropic ehrlichiosis has enabled advances in the investigation of these diseases. Beyond the research laboratory, his investigations have led to understanding of the pulmonary and renal pathophysiology of rickettsial diseases, host risk factors for severity of rickettsial disease, the epidemiology of human monocytotropic ehrlichiosis, and mechanisms of death in inhalational anthrax. The later was derived from his investigation of the 1979 outbreak of anthrax in Sverdlovsk, Russia, which was revealed to have been inhalational anthrax and for which he arranged further studies in Galveston by Russian colleagues. His field research projects and training of international scientists have ranged from Inner Mongolia, Sicily, Mexico, Peru, Brazil, Slovenia, and Japan to Cameroon.

With strong dedication to education he has participated in six different curricular approaches to teaching Pathology to medical students, established a Ph.D. graduate program in Experimental Pathology, and actively taught Autopsy Pathology to residents for 28 years.