system
Given the following post, respond as if you're commenting on Reddit:
human
Native Americans died from European diseases. Why was there not the equivalent introduction of new diseases to the European population?

Many Native Americans died from diseases introduced to them by the immigrating Europeans. Where there diseases new to the Europeans that were problematic? It seems strange that one population would have evolved such deadly diseases, but the other to have such benign ones. Is this the case?
gpt
There is a theory that Syphilis was brought back from the Americas by Spanish sailors. It is known that Syphilis was present in Pre-Columbian America but there is no recorded instance of an outbreak in Europe until 1495 when it broke out in the camp of French soldiers besieging Naples. From there it spread across Europe and would continue to be a major health issue in Europe until relatively recently.