History of Smallpox - Epidemics in The Americas

Epidemics in The Americas

After first contacts with Europeans and Africans, some believe that the death of 90–95% of the native population of the New World was caused by Old World diseases. It is suspected that smallpox was the chief culprit and responsible for killing nearly all of the native inhabitants of the Americas. For more than 200 years, this disease affected all new world populations, mostly without intentional European transmission, from contact in the early 16th century to until possibly as late as the French and Indian Wars (1754–1767).

In 1519 Hernán Cortés landed on the shores of what is now Mexico and was then the Aztec empire. In 1520 another group of Spanish arrived in Mexico from Hispaniola, bringing with them the smallpox which had already been ravaging that island for two years. When Cortés heard about the other group, he went and defeated them. In this contact, one of Cortés's men contracted the disease. When Cortés returned to Tenochtitlan, he brought the disease with him.

Soon, the Aztecs rose up in rebellion against Cortés and his men. Outnumbered, the Spanish were forced to flee. In the fighting, the Spanish soldier carrying smallpox died. After the battle, the Aztecs contracted the virus from the invaders' bodies. Cortes would not return to the capital until August 1521. In the meantime smallpox devastated the Aztec population. It killed most of the Aztec army and 25% of the overall population. The Spanish Franciscan Motolinia left this description: "As the Indians did not know the remedy of the disease…they died in heaps, like bedbugs. In many places it happened that everyone in a house died and, as it was impossible to bury the great number of dead, they pulled down the houses over them so that their homes become their tombs." On Cortés's return, he found the Aztec army’s chain of command in ruins. The soldiers who still lived were weak from the disease. Cortés then easily defeated the Aztecs and entered Tenochtitlán. The Spaniards said that they could not walk through the streets without stepping on the bodies of smallpox victims.

The effects of smallpox on Tahuantinsuyu (or the Inca empire) were even more devastating. Beginning in Colombia, smallpox spread rapidly before the Spanish invaders first arrived in the empire. The spread was probably aided by the efficient Inca road system. Within months, the disease had killed the Incan Emperor Huayna Capac, his successor, and most of the other leaders. Two of his surviving sons warred for power and, after a bloody and costly war, Atahualpa become the new emperor. As Atahualpa was returning to the capital Cuzco, Francisco Pizarro arrived and through a series of deceits captured the young leader and his best general. Within a few years smallpox claimed between 60% and 90% of the Inca population, with other waves of European disease weakening them further. A handful of historians argue that a disease called Bartonellosis might have been responsible for some outbreaks of illness, but this opinion is in the scholarly minority. The effects of Bartonellosis were depicted in the ceramics of the Moche people of ancient Peru.

Even after the two largest empires of the Americas were defeated by the virus and disease, smallpox continued its march of death. In 1561, smallpox reached Chile by sea, when a ship carrying the new governor Francisco de Villagra landed at La Serena. Chile had previously been isolated by the Atacama Desert and Andes Mountains from Peru, but at the end of 1561 and in early 1562, it ravaged the Chilean native population. Chronicles and records of the time left no accurate data on mortality but more recent estimates are that the natives lost 20 to 25 percent of their population. The Spanish historian Marmolejo said that gold mines had to shut down when all their Indian labor died. Mapuche fighting Spain in Araucanía regarded the epidemic as a magical attempt by Francisco de Villagra to exterminate them because he could not defeat them in the Arauco War.

In 1633 in Plymouth, Massachusetts, the Native Americans were struck by the virus. As it had done elsewhere, the virus wiped out entire population groups of Native Americans. It reached Mohawks in 1634, the Lake Ontario area in 1636, and the lands of the Iroquois by 1679. During the 1770s, smallpox killed at least 30% of the West Coast Native Americans. The smallpox epidemic of 1780–1782 brought devastation and drastic depopulation among the Plains Indians. This epidemic is a classic instance of European immunity and non-European vulnerability. It is probable that the Indians contracted the disease from the ‘Snake Indians’ on the Mississippi. From there it spread eastward and northward to the Saskatchewan River. According to David Thompson’s account, the first to hear of the disease were fur traders from the Hudson’s House on October 15, 1781. A week later reports were made to William Walker and William Tomison, who were in charge of the Hudson and Cumberland Hudson’s Bay Company posts. By February, the disease spread as far as the Basquia Tribe. Smallpox attacked whole tribes and left few survivors. E. E. Rich described the epidemic by saying that “Families lay unburied in their tents while the few survivors fled, to spread the disease.” After reading Tomison’s journals, Houston and Houston, have calculated that out of the Indians that traded at the Hudson and Cumberland houses, ninety-five percent died of smallpox. Paul Hackett adds to the mortality numbers suggesting that perhaps up to one half to three quarters of the Ojibway situated west of the Grand Portage died from the disease. The Cree also suffered a casualty rate of approximately seventy-five percent with similar effects found in the Lowland Cree. By 1785 the Sioux Indians of the great plains had also been affected. Not only did smallpox devastate the Indian population, it did so in an unforgiving way. William Walker described the epidemic stating that “the Indians all Dying by this Distemper … lying Dead about the Barren Ground like a rotten sheep, their Tents left standing & the Wild beast Devouring them.”

A particularly virulent sequence of smallpox outbreaks took place in Boston, Massachusetts. From 1636 to 1698, Boston endured six epidemics. In 1721, the most severe epidemic occurred. The entire population fled the city, bringing the virus to the rest of the Thirteen Colonies.

In the late 1770s, during the American Revolutionary War, smallpox returned once more and killed an estimated 125,000 people. Peter Kalm in his Travels in North America, described how in that period, the dying Indian villages became overrun with wolves feasting on the corpses and weakened survivors.

By 1832, the federal government of the United States established a smallpox vaccination program for Native Americans.

In 1900 starting in New York City, smallpox reared its head once again and started a sociopolitical battle with lines drawn between the rich and poor, white and black. In populations of railroad and migrant workers who traveled from city to city the disease had reached a endemic low boil. This fact did not bother the government at the time, nor did it spur them to action. Despite the general acceptance of the germ theory of disease, pioneered by John Snow in 1849, smallpox was still thought to be mostly a malady that followed the less-distinct guidelines of a "filth" disease, and therefore would only affected the "lower classes".

In Canada, between 1702–1703, nearly a quarter of the population of Quebec city died due to a smallpox epidemic.