The scandal over Guatemalans infected with sex diseases in the 1940s so that US researchers could test remedies has revived painful memories of a similar episode involving African-Americans in the 20th century.
US President Barack Obama personally apologized on Friday to Guatemalan President Alvaro Colom and "all those affected," by the experiment conducted by US public health researchers on hundreds of people in Guatemala between 1946 and 1948, the White House said.
In 1997, then president Bill Clinton similarly apologized for a study on treating syphilis that involved 400 black men who were recruited by medical authorities but were denied any treatment so researchers could study the progression of the disease.
The study on seasonal farm workers in the southern city of Tuskegee, Alabama, often described as the "Tuskegee experiment," took place between 1932 and 1972.
The two ordeals are linked together by one man. The chief researcher in the Guatemala study, controversial US public health doctor John Cutler, also played a major role in the Tuskegee experiment.
In fact, the Guatemala experiments came to light this year after Wellesley College professor Susan Reverby stumbled upon archived documents outlining the experiment led by Cutler, who died in 2003.
The main difference between the two experiments is that the Tuskegee men came to the study already infected with syphilis, unlike the Guatemalans who were deliberately infected by US researchers.
However, the Tuskegee men in many cases did not know they had the disease, only what was referred to culturally in the area as "bad blood," a syndrome that caused fatigue and other symptoms.
In Guatemala, the researchers infected female commercial sex workers with gonorrhea or syphilis, and then allowed them to have unprotected sex with soldiers or prison inmates. They tested penicillin on them as treatment so see how effective it was.
"What was done cannot be undone but we can end the silence," Clinton said in 1997.
"We can stop turning our heads away. We can look at you in the eyes and finally say, on behalf of the American people, what the United States government did was shameful and I am sorry."
The Tuskegee experiment has become a powerful symbol of racism in the medical domain, according to author James H. Jones who authored a 1991 book on the subject.
"Treatment was deliberately withheld from syphilitic men in an effort to determine the natural course of the disease, regardless of the human cost to the subjects, their wives and children or their communities," he said.
The study "was actually an ugly collaboration involving Public Health Service physicians, local private practitioners (white and black), the prestigious all-black Tuskegee Institute and Hospital, the county and state health departments, even draft boards," he said.
"It was the longest non-therapeutic experiment on human beings in medical history."
When a government review commission completed its analysis of the experiments, it described the effort as an "aberration, well intentioned but misguided."
The US government has paid around 10 million dollars to the families of the Tuskegee victims and the incident led lawmakers to pass legislation banning such experiments and regulating the way medical experiments are carried out on people.
