This essay has a total of 1449 words and 6 pages.


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

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)
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