The Impact of Infectious Disease in the New World “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.” (6) The decimation of people indigenous to the Americas by diseases introduced by European invaders is unprecedented. While it is difficult to accurately determine the population of the pre-Columbian Americas, scholars estimate the number to have been between 40 and 50 million people. The population in Mexico alone in 1519 is believed to have been approximately 30 million. By 1568, that number was down to 3 million inhabitants. Although there were other causes for the population reduction such as “alcoholism, warfare, genocide, cultural disruption, and declines in fertility”, it is now known that disease played a central role in the depopulation of the Americas. But how is it that these native peoples harbored virtually no immunity to the European diseases? What were these diseases and how did they come to be so feared? Who introduced them to this New World? How did this biological disaster affect the social structure of the Indians? This brief will attempt to answer the preceding questions.
How is the presence or absence of disease in the New World determined? Archeologists are able to determine if a society or individual fell prey to disease by examining teeth, bones, coprolites(feces), and artistic depictions. Through the excavations of burial mounds, scientists have discovered that certain afflictions existed even before the white man landed. “Missing limbs, skin diseases, blindness, cleft palate, clubfoot, “dental disease, parasites, arthritis, and tuberculosis are all thought to have existed in pre-Columbian America. However, tracing epidemiology in the 15th century is difficult because so little was done to identify and classify diseases and their symptoms during this time period. One might say that the New World was “ripe” for the onslaught of hitherto unknown diseases due to several demographic shifts prior to 1492.
These are parallel to shifts that occurred in Europe such as the creation of large urban areas. Since city planning wasn’t what it is today, cities were overcrowded, sewers were nonexistent or inefficient, and disease carrying vermin multiplied. This created a welcome mat for infectious disease in addition to the general uncleanliness of the population and the great number of transient people such as soldiers, students, thieves and the mentally ill. Another factor leading to the assault of disease on medieval Europe was the domestication of large mammals. These animals were the origins of some of the most cursed afflictions of the time.
Smallpox is a derivative of cowpox, measles of canine distemper, and influenza of hog diseases. “At first, neither young or old were spared. After generations, susceptible individuals were eliminated and resistant survivors dominated the gene pool. Diseases went from epidemics to childhood ills.” (6) It was in this form that diseases were carried to the New World by unsuspecting conquistadors, to a population that had experienced its’ own shifts to largely urban and sedentary lifestyles that become fertile ground for such an unseemly weapon of destruction. “Smallpox made its American debut in 1519, when it struck the Caribbean island of Santo Domingo, killing up to half of the indigenous population. From there outbreaks spread across the Antilles islands, onto the Mexican mainland, through the Isthmus of Panama and into South America.” (2) Some of the other diseases that followed this path were measles, plagues(bubonic and pulmonary), gonorrhea(from soldiers raping native women), mumps, typhoid, and cholera. Two African diseases, malaria and yellow fever, also came to Central American probably because of the ideal weather conditions in this region.
Prior to 1492, the Americas harbored relatively few infectious diseases. It is believed that the New World lived in virtual biological isolation from the rest of the planet due to the absence of domesticated animals and because of the path in which the Indians predecessors traveled. We know from origins of disease in Europe, that domesticated animals were to blame for the start of many epidemics. The New World lacked domesticated animals due to the extinction of large mammals, with which to draw from in the last ice age. Also, the remaining large mammals were not suitable for domestication for one reason or another.
At the time of migration across the North American land bridge, cattle and sheep were still not utilized by society and therefore were not a cause for the spread of disease. It is also believed that the path of migration across Beringia created a type of “germ filter” thanks to the harsh Arctic climate that killed off any bacteria or disease carriers such as worms or mosquitoes. In addition, the remoteness of clusters of migrants created a natural quarantine. By the time one group fell prey to an infectious disease they were unable to travel the great distances to infect other groups thereby extinguishing the disease. “While the New World had its native infections, including Chagas and Carrion’s diseases, trichinosis, tapeworm, and perhaps syphilis, few were deadly, and none (with the possible exception of syphilis), seriously threatened whole communities of European colonists.”(6) The impact that this biological isolation had on the conquest of the Americas is obvious.
Along with the weapons and horses that the Europeans brought to conquer the New World came disease. This was by far the most horrific instrument of destruction. After returning to Tenochtitlan from defeated a Spanish mission sent to est him and bringing with him only 1250 Spaniards and 8000 allied Tlaxcallan warriors, Cortes attacked the Aztecs which had pinned down the itinerant lieutenant left to govern them. His forces outnumbered and overcome by the Aztecs, he retreated and hours later Tenochtitlan was being ravaged by the previously unknown smallpox. It is believed that one of the soldiers picked up on the way back to Tenochtitlan by Cortes was suffering from smallpox.
This disease wiped out Aztec leaders and warriors and subsequently cleared the path for Cortes to retake the city of 1.5 million. This victory was clearly not attributable to advanced weaponry, horses, or military genius but rather disease. Upon returning to the city, Cortes chronicler 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 it..and even Cortes was ill from the odors which assailed his nostrils.'” (2) Indeed it is from these first hand accounts, not skeletal remains, which provide us with the most evidence of destruction caused by disease. These authors include Las Casas, Father Acuna, and Diaz del Castillo. Before long the smallpox epidemic spread all over Central and South America.
Infected natives, yet to develop symptoms, would flee their villages and travel to other villages carrying the disease with them. “..that any Indian who received news of the Spaniards could also have easily received the infection.” (2) The reason that smallpox traveled so fast is because it could live in a dormant state on blankets and clothing or be transmitted by human breath. The incubation …