It's estimated that between 60 to 65 percent of American soldiers stationed in the South Pacific during WWII suffered from a malarial infection at some point during their service. For some units the infection proved to be more deadly than the enemy forces were, so finding an effective treatment was a high priority [source: Army Heritage Center Foundation]. Safe anti-malarial drugs were seen as essential to winning the war.
Beginning in 1944 and spanning over the course of two years, more than 400 prisoners at the Stateville Penitentiary in Illinois were subjects in an experiment aimed at finding an effective drug against malaria. Prisoners taking part in the experiment were infected with malaria, and then treated with experimental anti-malarial treatments. The experiment didn't have a hidden agenda, and its unethical methodology didn't seem to bother the American public, who were united in winning WWII and eager to bring the troops home — safe and healthy. The intent of the experiments wasn't hidden from the subjects, who were at the time praised for their patriotism and in many instances given shorter prison sentences in return for their participation.