Max Theiler working on yellow fever. In 1926, they disproved Hideyo Noguchi's hypothesis that yellow fever was caused by the bacterium "Leptospira icteroides." In 1928, the year after the disease was identified conclusively as a virus, they showed that the African and South American viruses are immunologically identical. (This followed Adrian Stokes' inducing yellow fever in rhesus macaques from India). In the course of this research, Theiler contracted yellow fever, but survived and developed immunity. In 1930, Theiler moved to the Rockefeller Foundation in New York, where he later became director of the Virus Laboratory. He was professor of epidemiology and public
Gertrud Theiler Africa, was named after Dr. Theiler in honor of the many years she dedicated to the collection. The argasid tick "Argas theilerae" (Hoogstraal and Kaiser, 1970), "Theiler's African white-backed vulture argasid," and the ixodid tick "Rhipicephalus gertrudae" (Feldman-Muhsam, 1960) were named to honor Dr Theiler for her many contributions to tick research. Theiler was the youngest daughter of Sir Arnold Theiler , founder and first director of the Veterinary Institute, Onderstepoort, and his wife, Emma Sophie Jegge; in 1971, she authored a biography of her father. She was a sister of virologist Max Theiler, who was awarded the 1951 Nobel