The history of Native American disease and epidemics is fundamentally composed of two elements: indigenous diseases and those brought by settlers to the Americas from the Old World (Africa, Asia, and Europe), which transmitted far beyond the initial points of contact, such as trade networks, warfare, and enslavement. The contacts during European colonization of the Americas were blamed as the catalyst for the huge spread of Old World plagues that decimated the indigenous population.
Epidemics of smallpox, typhus, influenza, diphtheria and measles swept the Americas subsequent to European contact, killing between 10 million and 100 million people, up to 95% of the indigenous population of the Americas.