Although a variety of infectious diseases existed in the Americas in pre-Columbian times, the limited size of the populations, smaller number of domesticated animals with zoonotic diseases, and limited interactions between those populations (as compared to areas of Europe and Asia) hampered the transmission of communicable diseases. One notable infectious disease of American origin is syphilis. Aside from that, most of the major infectious diseases known today originated in the Old World (Africa, Asia, and Europe). The American era of limited infectious disease ended with the arrival of Europeans in the Americas and the Columbian exchange of microorganisms, including those that cause human diseases. Eurasian infections and epidemics had major effects on Native American life in the colonial