A lost disease emerges from 5,500-year-old human remains

A 5,500-year-old skeleton from Colombia has revealed the oldest known genome of the bacterium linked to syphilis and related diseases. The ancient strain doesn’t fit neatly into modern categories, hinting at a forgotten form that split off early in the pathogen’s evolution. This pushes the history of treponemal diseases in the Americas back by millennia and shows they were already diversifying long before written records.