The HIV/AIDS epidemic exploded in the 1980s, but new research shows HIV was plaguing the human population in Africa for a century before that. Old collections of human tissue samples from the Congo have produced evidence of old strains of HIV that may have emerged in 1908, reports Nature.
Studying older strains of HIV can show researchers how modern strains came into existence and could help in the battle against the disease. Researchers caution that they may never pinpoint exactly how HIV crossed from chimpanzees, where scientists believe the disease began. But "we would love to know what caused this strain to move out of 'starlet' phase and to the big time," said a virologist.