Jesse: [link]
Osteologic data demonstrate that native groups were most definitely not living in a pristine, disease-free environment before contact. Although New World indigenous disease was mostly of the chronic and episodic kind, Old World diseases were largely acute and epidemic. Different populations were affected at different times and suffered varying rates of mortality.19 Diseases such as treponemiasis and tuberculosis were already present in the New World, along with diseases such as tularemia, giardia, rabies, amebic dysentery, hepatitis, herpes, pertussis, and poliomyelitis, although the prevalence of almost all of these was probably low in any given group.14 Old World diseases that were not present in the Americas until contact include bubonic plague, measles, smallpox, mumps, chickenpox, influenza, cholera, diphtheria, typhus, malaria, leprosy, and yellow fever.19 Indians in the Americas had no acquired immunity to these infectious diseases, and these diseases caused what Crosby referred to as “virgin soil epidemics,” in which all members of a population would be infected simultaneously.20