 The causative organism , Treponema pallidum , was first identified by Fritz Schaudinn and Erich Hoffmann in 1905 . The first effective treatment ( Salvarsan ) was developed in 1910 by Paul Ehrlich , which was followed by trials of penicillin and confirmation of its effectiveness in 1943 . Before the discovery and use of antibiotics in the mid @-@ twentieth century , mercury and isolation were commonly used , with treatments often worse than the disease . 
