 "T. pallidum" is also detected by serology, including nontreponemal VDRL, rapid plasma reagin, treponemal antibody tests (FTA-ABS), "T. pallidum" immobilization reaction, and syphilis TPHA test.During the early 1940s, rabbit models in combination with the drug penicillin allowed for a long term drug treatment.These experiments establish the ground work that modern scientists use for syphilis therapy.