<P> Diseases introduced to the Americas by European colonizers--and their African slaves--include smallpox, yellow fever, measles and malaria, as well as new strains of typhus and influenza . </P> <P> Virgin soil epidemics also occurred in the Old World prior to the Age of Discovery . For example, the Romans spread smallpox through new populations in Europe and the Middle East in the 2nd century AD, and the Mongols brought the bubonic plague to Europe and the Middle East in the 14th century . </P> <P> Research over the last few decades has problematized the notion of Virgin Soil epidemics . David S. Jones has argued that the term "Virgin Soil" is often used to describe a genetic predisposition to disease infection, and obscures the more complex social, environmental, and biological factors that can enhance or reduce a populations susceptibility. . Paul Kelton has argued that the slave trade in Indigenous people by Europeans exacerbated the spread and virulence of smallpox and that a "Virgin Soil" model alone cannot account for the widespread disaster of the epidemic . Cristobal Silva has re-examined accounts by colonists of 17th century New England epidemics and has explored how they were products of particular historical circumstances rather than universal or genetically inevitable processes . </P>

Virgin soil epidemics as a factor in the aboriginal depopulation in america