Apparently native populations had a different immunogenic profile and that made them more susceptible to European diseases such as smallpox, and this was amplif

Apparently native populations had a different immunogenic profile and that made them more susceptible to European diseases such as smallpox, and this was amplified by the lack of any immunity acquired by childhood exposures: https://psmag.com/news/how-native-american-genes-tell-the-story-of-europeans-arrival https://psmag.com/news/how-native-american-genes-tell-the-st... Charles C. Mann has a whole chapter on the epidemics that ravaged the Americas after the European arrival, in "1491: New Revelations of the Americas Before Colombus (2005)", and discusses this and other theories. https://www.goodreads.com/book/show/39020.1491 https://www.goodreads.com/book/show/39020.1491