The Europeans were said to be thoroughly diseased by the time Columbus set sail on his first voyage (Cowley, 1991). Through the domestication of such animals as pigs, horses, sheep, and cattle, the Europeans exposed themselves to a vast array of pathogens which continued to be spread through wars, explorations, and city-building. Thus any European who crossed the Atlantic was immune to such diseases as measles and smallpox because of battling them as a child.
The original inhabitants traveled to the New World in groups of a couple hundred each. Because microbes such as the ones that cause measles and smallpox need populations of several million to survive, the original populations were unaffected by the deadly diseases. However, by the time Columbus arrived, the major Indian groups of Aztecs, Incas, and Mayas had built their populations up enough to sustain mass epidemics. Evidence shows that these populations suffered from such diseases as syphilis, tuberculosis, a few intestinal parasites, and some types of flu, but not the diseases that had been infecting the Old World for centuries. Thus when the Europeans arrived bringing diseases such as smallpox, measles, whooping cough, etc. the natives were immunologically defenseless (Cowley, 1991).
It is believed that 40 million to 50 million people inhabited the New World before the arrival of Columbus and the Europeans, and that most of them died within a few decades. For example, Mexico 's population fell from about 30 million in 1519 to 3 million in 1588. The other South and Central American countries as well as the Caribbean islands suffered the same devastation (Cowley, 1991). Mass epidemics were virtually unknown in the New World prior to the invasion of the Europeans. Aside from their
Bibliography: Cowley, Geoffrey. "The Great Disease Migration." Newsweek (Special Issue, Fall/Winter 1991) pp. 54-56 Crosby, Alfred W. Jr. The Columbian Exchange: Biological and Cultural Consequences of 1492, Westport: Greenwood Press, 1972 Assignment: Write a short review of this paper for class on Friday. In addition, overwhelming historical evidence suggests that the greatest rates of morbidity and death from infection are associated with the introduction of new diseases from one region of the world to another by processes associated with civilized transport of goods at speeds and over distances outside the range of movements common to hunting and gathering groups. (excerpt from book of same title: pp. 131-141) Cohen, M. Health and the Rise of Civilization. New Haven: Yale University Press, 1989.