I've read a lot about epidemics from germs brought over by colonizers killing off huge numbers of indigenous people in the Americas, and this being replicated (if not to the same extent) in other places globally.
Why I want to know is why a similar transfer of germs didn't effect people coming from Europe? Why were there no infectious diseases that went in the other direction, so to speak?
This question is relatively common, so before othe rresponses come in, you might be interested in the FAQ entries that refer to this issue, such as: this response by u/anthropology_nerd, this thread, with the entries by u/anthropology_nerd and u/400-Rabbits or this entry by u/400-Rabbits.