1899-1972

South African-American microbiologist who was awarded the 1951 Nobel Prize for physiology or medicine for his research on yellow fever. Theiler's discovery that mice are susceptible to yellow fever expedited research on the disease and made possible the development of an attenuated strain of the virus. Theiler and his associates developed an improved vaccine that is widely used to protect humans against yellow fever. Theiler made many other contributions to tropical medicine and the study of infectious diseases.