From 1946-1948, the US Public Health Service deliberately infected over 5,500 Guatemalan prisoners, sex workers, soldiers, children, and psychiatric patients with syphilis, gonorrhea, or chancroid. Subjects were infected through sex workers, open wounds, or direct urethral insertion of bacteria — all without consent. The same principal investigator (Dr. John Charles Cutler) also ran the Tuskegee experiment. The experiments were hidden until historian Susan Reverby discovered them in 2010. Obama apologized to Guatemala.