Syphilis got milder a century or so after the Indians first infected the white man with it.
I had never heard of that. But you may be right ----- [Wikipedia] As Jared Diamond describes it, "[W]hen syphilis was first definitely recorded in Europe in 1495, its pustules often covered the body from the head to the knees, caused flesh to fall from people's faces, and led to death within a few months." The disease then was much more lethal than it is today.[21]
The flesh from faces thing -- noses would fall off, and blindness occur. Sounds like leprosy! It does seem to have come back to Europe on Columbus' ships. He brought them tuberculosis and malaria, so maybe we're even, re Columbus. Later Spaniards took a lot more diseases over to the Americas. 90% of the North American Indians died of epidemics, I've read, so it was easy to take over this New World.
And to think we complain about COVID ------