Silent Killers of the New World


Elizabeth Orlow

The European conquest of the New World was not caused by guns, swords, or barbaric type behavior but by the invisible danger-germs. Infectious diseases have played a major role in shaping the conquest of the New World. Vast amounts of people indigenous to the Americas died due to various types of diseases. It is often said that in the centuries after Columbus landed in the New World on 12 October 1492, more native North Americans died each year from infectious diseases brought by the European settlers than were born (Meltzer 38). Disease was the principle reason for the demise of the Indians.

Most infectious diseases result from a microparasite. Microparasites may be thought of as those parasites, which have direct reproduction, usually at high rates within the host (Anderson 13). Their short generation time and size characterize them. Microparasites also go through two stages until an infection leads to a disease. The period from the point of infection to the appearance of symptoms is termed the incubation stage. At this stage, symptoms may not be extremely prevalent, and the person can infect others. The incubation period is the most critical stage, because the microparisite is lying dormant, and unknowingly the disease can be spread. The period from the point of infection to the stage of infectiousness is the latent stage. If a host recovers from an infection he or she has acquired immunity to the disease and are not re-infected.

Many types of diseases were brought into the Americas. The main diseases were smallpox, measles, influenza, and typhus. There were also other diseases such as whooping cough, the mumps, and diphtheria. Each disease has a specific entry into the body, and each can cause various types of symptoms. For example, diphtheria enters the body through the respiratory tract and attaches to the tissue in the throat. This disease can cause a blockage of the air passage to the lungs and can cause suffocation or death. Whooping cough is also highly contagious and can cause violent coughing. The person can also turn blue, due to the lack of oxygen, vomit, or go into convulsions. Influenza virus that infects people does not infect other hosts. Influenza is transmitted through air droplets expelled by coughing or sneezing. Measles is a highly contagious viral disease, which can enter the body through the eye or respiratory tract. Symptoms such as a rash, high fever, delirium, and eye pain can occur. Mumps also occurs in the respiratory tract and later the infection can spread throughout the body. Swelling of the glands can occur. Typhus is considered a vector-borne disease meaning an intermediate host is involved. Symptoms include fever, weakness, and hemorrhagic rash. Smallpox is a virus that enters the respiratory tract. Symptoms include lesions on the body, fever, exhaustion, chills, and headaches.

The origin of disease in the New World and the Old World is very different. In the Old World, Europeans had already come in contact with various types of infectious disease and acquired immunity. The Europeanís genes also became resistant overtime. Through natural selection the relative frequency of a gene appears to change over generations. For an example, people who have acquired resistant genes over generations are more likely to survive various types of diseases. Also, when the human population becomes larger a disease is sustained better. One of the reasons why the Europeans acquired immunity to various diseases was due to domesticated animals. The reason for this was because the Europeans lived in close proximity to the animals. Since domesticated animals are considered breeding grounds for several diseases, it was not long before diseases were transferred to humans from animals. Europeans were infected by a wide variety of pathogens by domesticating pigs, cattle, sheep, and horses (Cowley 1). Measles, samllpox, and diphtheria apparently originated in cattle, and influenza came from pigs or chickens (Cohen 47). There is also a specific pattern of how disease is transmitted from animals to humans. First, the human can pick up an animal-borne microbe. Second, the pathogen can evolve to a degree to where it can be transmitted from person to person. Third, the pathogen can establish itself in the human body and an epidemic disease can start to occur.

In the New World, however, there were only a few domesticated animals, which did not carry harmful pathogens, therefore, the transference of disease from animals to humans was unlikely. The New World was considered virtually disease-free. Also, many of the native communities were isolated from each other, therefore, the transmission rate decreased, preventing the spread of disease. This reason is probably why, for example, smallpox did not originate or spread within the communities until the arrival of the Europeans. The microbe that causes measles, smallpox, and other diseases require several million people to sustain them (Cowley 1). Also the New World was considered "virgin soil" which is a population made up of nonimmune individuals. Typically this type of area can cause problems because people of all ages are infected at once and the death rate is extremely high. Since the New World had no exposure to the Old World diseases and the people were neither immunologically nor genetically resistant to disease, severe outbreaks of disease was destined to occur once the Europeans arrived.

One disease that affected both the Old and the New World was smallpox. For many years, smallpox was present in Europe killing vast amounts of the population. The disease had a particular way of flowing through the population. If the population was to small to sustain the disease it would be "dormant" but if the population increased the disease would reappear. Children were infected the most by smallpox, however, some children were able to fight off the disease and acquire immunity for life. Adults, therefore, were immuned to the disease. Even though other harsh disease were present in Europe smallpox was the most severe.

The introduction of smallpox to the New World had a very different effect. Because native populations had no previous exposure to smallpox, they had no resistance to the infection. The infections became extremely deadly to the natives. A numbers of Indians were killed due to the effects of pathogen transmission. Disease played an important role in the Spanish conquest of the Aztec and Inca empires.

One effect was the accidental exposure of smallpox to the Aztecs. In 1519, Cortes landed on the coast of Mexico with 600 Spaniards to conquer the strong military force of the Aztec Empire. At this time, the population was in the millions. Cortes and his army marched into Tenochititlan and arrested Montezuma. As Cortes later tried to escape with the treasures, the Aztecs attacked him. Many Aztecs and Spanish died. Unknown to the Aztecs the Spanish had an invisible advantage. Apparently, one Spaniard soldiers was infected with the smallpox virus. Within two weeks the disease infected the Aztec Empire and one forth of the population died. By 1618, Mexico's initial population of 20 million had plummeted to about 1.6 million (Cohen 8). Francisco Lopez de Gomana, Cortesís secretary, states, "it spreads form one Indian to another, and they, being numerous and eating and sleeping together, quickly infected the whole country." Later, the Spaniards were able to conquer Mexico because of the weak military resistance of the Aztec Empire.

The smallpox epidemic also traveled to the Inca Empire. Pizarro landed on the coast of Peru in 1531 with 200 men to conquer the Inca Empire. Fortunately for Pizarro, smallpox had already spread through the region. The leader of the Inca emperor Huayna Capac and his successor Ninau Cuyode were killed by the epidemic. Civil war broke out in Peru and the political structure disintegrated. Since the Incas had no military resistance to smallpox, the Spanish were able to conquer the Incas. The Inca Empire went from 9 million to 14 million occupants, so in the 1520ís only 1 million people arrived. In a few short years later, 94% of the population was gone (Stannard 90). Since the Incas and the Aztecs had no military resistance due to the epidemic, the Spanish were able to conquer these areas. The main reason why smallpox spread so fast was because it could lie dormant in blankets and in clothing or it could be transmitted by human breath. Also the incubation period was very long, 10-14 days, and the disease could easily been spread unknowingly.

One disease that may have originated in the New World was syphilis. Syphilis reached epidemic proportion in Europe in the 16 century. It spread rapidly and caused suffering. In Europe at the time of the outbreak, syphilis caused postulates all over peopleís body, flesh came off, and death occurred in a few months. Even though Europe experienced devastating effects it was nothing like the effect epidemics had in the New World. Most evidence supports the theory that the disease originates in the New World and was transmitted sexually to invading Spanish by Indian women. This conclusion was made because in 1492 syphilis was found in the Spanish ports were sailors were treated for the disease. The timing of the first outbreak of syphilis in Europe and the pace where it occurred certainly seems to fit if the disease was imported from America by Columbusís returning sailors (McNeill 219). Others claim that syphilis was an introduced pathogen and it lacked potency due to the built up immune system of the Europeans. Also people claimed that there were no reports of infection during 1492.

Disease created a positive effect for the Europeans and a negative effect on the Indians. The diseases the Europeans spread made the Natives sick and weak, therefore the Europeans could invade easier and conquer areas due to the lack of military resistance. Disease also worked in favor of the Christians. It supported the idea that God wanted Europe to expand and control the New World. Americaís possessions and dignity were taken which fueled the Europeans belief that it was Godís will. The one problem the Europeans had with the conquest was the Indian population was almost completely eradicated. Despite all the death the Europeans caused the Natives, the Europeans wanted the natives for labor, guides, and translators. Since the Natives were dying the Europeans began to bring in African slaves who had strong immunity to disease like the Europeans. Bringing in African slaves also caused more disease to be brought to the New World, which resulted in more Indian deaths. The Europeans were not affected by the Indians deaths and more African labor was required.

The Indians suffered negative effects. The belief system of the Indians was destroyed. The Indians lost hope in their gods and the result was Indians turning to the missionaries to convert. Both the Spanish and the natives agreed that the epidemic diseases were dreadful and unambiguous forms of divine punishment a sign of Gods displeasure (McNeill 207). The Indians believed this idea because the Europeans were not dying from disease like the Indians were. The Indians also became too weak to care for their children and their crops. It is also believed many Indians eventually became depressed by the devastating effects of disease and became suicidal.

Europeans entered the New World and did great injustice to the Indians indigenous to the land. The European ideas and disease destroyed a unique culture and an amazing race of people. Because of the spread of disease, the Europeans were able to push through the New World with great ease and cause the Indians to become mentally and physically defeated. Europeans were diseased people with strong immunity while the Indians were healthy but lacked immunity. One can say it was not the weapons the Europeans had that conquered people of the New World but rather the silent killer Ėdisease.

Woks Cited

Anderson, Roy. Infectious Diseases of Humans. New York: Oxford University Press, 1989.

Cohn, Mark. Health and Rise of Civilization. New Haven: Yale University Press, 1989.

Cowly, Geoffrey. The Great Disease Migration. Newsweek, Fall-Winter 1991 vol. 118, pg. 54

McNeill, William H. Plagues and Peoples. Garden City: New York, 1976.

Meltzer, David J. How Columbus Sickened the New World. New Scientist, Oct. 10,1992 vol. 136 pg.38

Stannard, Paul. American Holocaust. New York: Oxford, 1992.