Complex sentence: Scientists eventually used this information to trace the detection of the virus entering the United States in 1966, when Dugas was still a "virginal adolescent," before entering the U.S., the virus came from the Caribbean country Haiti.
Split into simpler sentences: Scientists eventually used this information to trace the detection of the virus entering the United States in 1966, when Dugas was still a "virginal adolescent". Before entering the U.S., the virus came from the Caribbean country Haiti.