The greatest adversary to the natives in the Americas was not the swords or guns of the invaders. It was the devastation brought by deadly diseases infecting an unsuspecting population that had no immunity to such diseases.
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 lack of immunity to the pathogens, another factor in the rapid spread of the diseases could have been the weariness of the Indian populations. Due to their recent conquest and oppression by the Spaniards, the Indians were probably too tired to fight the infections.
One thing that must be noted is that contrary to popular belief, infectious agents such as viruses, bacteria, parasites, etc. are not designed to cause harm. Rather they survive better when they don't destroy their hosts. The greatest harm occurs when a germ infects a previously unexposed population. It often causes massive epidemics of which only the most resilient individuals survive. As natural selection weeds out the most susceptible hosts and the survivors repopulate, what was once a deadly disease becomes a routine childhood illness.
The first major disease to find the New World was probably smallpox which broke out on Hispanola in 1518. As the Spaniards moved toward the mainland from the islands their diseases often proceeded them. One reason for this was a messenger bearing the news of the invasion to his people could carry the diseases as well as his message. With the arrival of Cortes in 1520 the smallpox virus was brought to Mexico and the Aztec nation. It has been thought that if the virus had not come when it did the Spanish invasion would not have been successful (Lunenfeld, 314). The Aztec leader of the assault against the Spanish invasion, as well as many of his followers, died after ordering the Spaniards out of Tenochtitlan. If the people would have continued with what they had started, they would not have been conquered for before August 21, 1521, the Spaniards were almost defeated. However in a siege that lasted seventy-five days the dead Aztecs from combat, starvation, and disease numbered into the 1000's (Crosby, 1972). The massive numbers of dead stunned the people so much that they were unable to react. The natives were not the only ones affected by the dead, however, for the invaders were also affected. One Spaniard, Bernal Diaz, wrote, "I solemnly swear that all the houses and stockades in the lake were full of heads and corpses. It was the same in the streets and courts. . . We could not walk without treading on the bodies and heads of dead Indians. . . Indeed, the stench was so bad that no one could endure." (Crowley, 1991) The smell even caused Cortes to become ill.
The smallpox epidemic was not just confined to the Aztecs, however. By 1525 or 1526 the virus had reached the Incan Empire. The death of the Incan ruler as well as most of his family including his heir, caused the fall of the Incan political structure and divided the people. When Pizarro arrived he met with little or no resistance and easily conquered the Incas. One of Pizarro's soldiers said, "Had the land not been divided, we would not have been able to enter or win." (Crowley, 1991)
Smallpox among other illnesses left the populations too weak to harvest food or even feed their young. As a result some populations dies out almost immediately, while others continued to hang on for 100-150 years after surviving harsh epidemics.
Both the Indians and the Spaniards felt that the epidemics were a divine punishment from God. The majority of the Indians, while some accepted the Christian God of the Spaniards, believed in gods that were often angry with humans. The Spaniards saw pestilence as a punishment of God, a belief that was rooted in the Old Testament. Another reason the Indians agreed with the assumption of the Spaniards was that they had no prior experience with such epidemics before and therefore acquired no immunity to them as the Spaniards had and they were extremely frightened of the diseases.
Their experiences caused unavoidable changes in the lives of the natives. When persuaded that their ancestral gods abandoned them, the Indians were more easily convinced to accept Christianity. The Spaniards immunity to smallpox and the Indians extreme susceptibility to is caused the Indians to believe that the Spaniards had a shield of the gods themselves. The Indian nations were also divided . Their political structures were damaged with the death of leaders and the process by which they were replaced hampered. For example, in the Aztec nation, when Moctezuma died his nephew Cuitlahuac took over until he died of smallpox during the siege (Crowley, 1972).
In addition to the diseases brought to the New World from the Old, the New World also provided the Old World with at least one new disease as well. The disease was syphilis. Records show that syphilis in Columbus' time was very similar to leprosy (Lunenfeld, 315). No records of this disease were found before Columbus returned from his voyage. It is very unlikely that a disease so virulent, if it had existed, would never have been mentioned.
The epidemics not only destroyed the native populations, but they also effected other people groups. One such group was the Africans. With the decline of an available work force among the natives, the Spaniards resorted to importing African slaves because they didn't want to do the work themselves. The Africans had the same immunities as the Europeans and thus made better slaves than the natives.
Columbus may have initiated the first major change in the world's epidemiological landscape. However human activity is still changing and thus creating prime environments for new disease causing agents. A case in point is the HIV virus which causes AIDS. AIDS threatens to destroy entire nations. While no one knows where AIDS came from, it is thought to be like syphilis in that it was haunting isolated populations before becoming global. And just as syphilis was carried globally by ships; jet planes and world-wide social changes have brought AIDS out of isolation. Like smallpox and other infectious diseases in the 16th century and AIDS in the 20th century, what new disease will hit and destroy unsuspecting populations?
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.