Why were the native americans so ravaged by european diseases but the europeans were not equally sickened. I understand that the slavery and malnutrition that natives suffered as a result of european conquest added to the issue, but shouldn't there have been some widespread sickness present in europe as a result of contact?
While there is plenty of room for more discussion, this section of the FAQs has information that you need. Look at the entries by u/anthropology_nerd.