MEXICO CITY — Exposing a dark page in its history, the U.S. government acknowledged Friday that government scientists had infected some 1,500 Guatemalans with syphilis and gonorrhea in experiments from 1946 to 1948 in "appalling violations" of medical ethics.
U.S. scientists infected prostitutes with syphilis or gonorrhea and sent them to have unprotected sex with soldiers or prison inmates, later testing them for possible cures, U.S. officials said.
When few became infected, scientists turned to patients at a mental health hospital, exposing them to infection by rubbing it on their genitals.
None of the subjects were informed about the study or offered consent, U.S. officials said.
"Although these events occurred more than 64 years ago, we are outraged that such reprehensible research could have occurred under the guise of public health," Secretary of State Hillary Clinton and Health and Human Services Secretary Kathleen Sebelius said in a joint statement.
"We deeply regret that it happened, and we apologize to all the individuals who were affected by such abhorrent research practices."
The statement said current regulations prohibit such "appalling violations" of ethics regarding human medical research and added that the two departments would launch "a thorough investigation" of the 1946-1948 study in Guatemala.
Clinton called President Alvaro Colom of Guatemala on Thursday night "to express her personal outrage, deep regret," Arturo Valenzuela, the assistant secretary of state for Western Hemisphere affairs, said in a message on Twitter.
Colom voiced anger on Friday: "These should be considered crimes against humanity and Guatemala reserves the right to petition the relevant international court at an opportune time."
Friday's acknowledgment shed new light on U.S. medical experiments that included the infamous Tuskegee study in which scientists observed, but didn't treat, hundreds of African-American men with late-stage syphilis in Macon County, Ala., starting in 1932 until it was exposed by the media in 1972.
A Wellesley College professor of history and women's studies, Susan M. Reverby, discovered evidence of the secret U.S. tests in Guatemala while examining papers on the Tuskegee study held at the University of Pittsburgh archives.
The papers showed that a U.S. Public Health Service team led by physician John C. Cutler infected men and women in the Guatemalan National Penitentiary, an army barracks, and a mental health hospital.
Cutler had little difficulty winning Guatemalan support for the study through pledges of medicine, such as penicillin and an anti-convulsant drug for epileptics.