1876-1949

English microbiologist who demonstrated that relapsing fever in monkeys is transmitted by infected ticks (Ornithodorus moubata). Philip Hedgeland Ross and Arthur Dawson Milne also made this discovery independently at about the same time. The causative agent was named Borrelia duttoni. In the course of their work, in what was then the Congo Free State, both Todd and his research partner, Dutton, contracted the disease. Dutton died of "tick fever" before their landmark paper was published in the British Medical Journal in 1905. In collaboration with Simeon Burt Wolbach and F. W. Palfrey, Todd proved that Rickettsia prowazekii is the causative agent of typhus fever.