I think that was debunked. Syphilis is actually present in all regions, and previously spread throughout eurasia.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3956094/#:~:text=Throughout%20the%20centuries%2C%20syphilis%20has,prevention%20programs%20control%20the%20disease.

I learned a bit reading here. It was more mild according to that write-up, but evolved to become more brutal. Interesting point, it mentions that in Europe it was mistaken for leprosy, so she may have decided to be sealed in due to the similarities in her condition. Hard to say.