On Oct, 26, 2016, a team of researchers at the University of Arizona and University of Cambridge in the U.K. announced they had reconstructed the origins of the AIDS pandemic in unprecedented detail.

The study, published in the journal Nature, confirmed previous findings that retraced the routes by which the virus entered and spread through the U.S. and eliminated any remaining doubt surrounding the Caribbean region as a key steppingstone from which HIV jumped into the U.S. Gaetan Dugas, a flight attendant for Air Canada, was incorrectly identified as “Patient Zero.”

The results are important for two reasons. In clinical terms, they show that Dugas’s virus was, in many ways, unexceptional. And in human terms, they clear his name.