The Europeans brought smallpox with them, and the Americans gave them syphilis. Or so it appears:
A study published in 2011 has systematically compared these European skeletons, using rigorous criteria for bone diagnosis and dating. None of the candidate skeletons passed both tests. In all cases, ambiguity in the bone record or the dating made it impossible to say for certain that the skeleton was both syphilitic and pre-Columbian. In other words, there is very little evidence to support the pre-Columbian hypothesis. It seems increasingly likely that Columbus and his crew were responsible for transporting syphilis from the New World to the Old.
Katherine Wright, the author of the article, also makes a useful note about DNA in the comments:
Researchers amassed all of the laboratory and field strains available of these weird and wonderful treponemes from across the globe, sequenced sections of their DNA, and then mapped the DNA changes among them. Using these DNA changes, they constructed an evolutionary “family” tree charting how the strains are related in evolutionary time. This so-called phylogenetic analysis has suggested that venereal syphilis is the youngest of the diseases, arising most recently in evolutionary time. Furthermore, the bacterial strains causing venereal syphilis are most closely related to yaws-causing treponemes from South America. This again suggests a New World origin for syphilis.
I should note that the rest of the comments contain a number of quite abominable puns, which should avoided at all costs. I can’t repeat any here, as this is a family blog.
The treatment for syphilis was, until the discovery of antibiotics, perhaps more deadly than the disease itself. Mercury was used as a balm, never mind its horrendously toxic side effects. In the 19th century, doctors experimented with something called “syphilization,” which, well, I’ll let someone else explain:
“Syphilization” was the name given to repeated inoculations with syphilis matter in order to “saturate” the subject, on the theory that the larger the number of visible, or “primary,” lesions, the less likely it was that secondary syphilis would develop.