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
Arnold Theiler and had two sons and two daughters, the younger two of whom worked at Onderstepoort: Hans (1894–1947), a veterinarian; Margaret (1896–1988), a teacher; Gertrud (1897–1986), a parasitologist and professor; and Max Theiler (1899–1972), a Nobel laureate in 1951 in Physiology and Medicine. Arnold Theiler Sir Arnold Theiler KCMG (26 March 1867 – 24 July 1936) Pour le Mérite is considered to be the father of veterinary science in South Africa. He was born in Frick, Canton Aargau, Switzerland. He received his higher education, and later qualified as a veterinarian, in Zurich. In 1891 Theiler travelled to South Africa and at