We always hear of the Old World bringing disease to the New World. What diseases did the New World introduce, and why were there no huge losses of Old World lives to New World diseases, like smallpox caused to the Native Americans?

Hi, not discouraging new information on this, but fyi, this is a fairly popular question in this sub, so we've collected some great threads into a FAQ section, Impact of indigenous diseases on the Europeans. Here are the posts:

Impact of indigenous diseases on the Europeans

One of the main reasons Europeans were so utterly victorious against Native Americans was the introduction of diseases, that decimated the population. Why did the Norsemen of Vinland not bring diseases that carried the same effect? by /u/anthropology_nerd
I am a native american living in the 1600s, someone in my village has just contracted small pox. What happens next? by /u/anthropology_nerd
When Europeans brought diseases to the new world, how come Europeans themselves didn't get sick from diseases specific to the new world? by /u/anthropology_nerd
Why weren't European settlers in North America decimated by disease like the native populations? by /u/400-Rabbits