Several years later, it was Worobey who detected evidence of HIV in a certain Congolese biopsy specimen from 1960. Worobey amplified fragments of the viral genome, pieced the fragments together, recognized them as an early version of HIV-1, and named the sequence DRC60. Comparing his sequence with ZR59, the other earliest known strain, he reached a dramatic conclusion: that the AIDS virus has been present in humans for decades longer than anyone thought. The pandemic may have gotten its start with a spillover as early as 1908.
