A Pox upon U.S. (1774–1882)

Pox Americana. Elizabeth A. Fenn. New York: Hill and Wang; 2001. 370 pages. $25.00. ISBN: 0809078201

Pox Americana is an extensively documented and extremely detailed account of the smallpox epidemic that swept North America between 1774 and 1882. This catastrophe was never covered in any of the history classes I took, and the omission is surprising, given the considerable number of fatalities and the pervasive historical ramifications. During the period, a documented 130,000 North Americans died of smallpox, a figure that likely underestimates the actual death toll by several orders of magnitude: countless deaths in various Indian villages or Mexican towns were never recorded.

Remember that this was a time when the only people inhabiting the United States between what is now California and Kentucky were the Native American tribes. In addition to taking thousands of lives, the epidemic, as detailed by the author, had indirect and far-ranging effects, including a significant role in determining the strategies for many of the battles of the Revolutionary War. It also changed the dynamics among warring Native Americans, resulting in the annihilation of certain tribes. It facilitated the spread of Catholicism in New Spain (i.e., modern Mexico and the southwestern United States) much more quickly than the local priests could have done. It prompted treaties between native tribes and the Spanish. It weakened Native American resistance along the Anglo-American border, and allowed the soon-to-be-independent U.S. citizens to push west.

The book begins with a description of smallpox, its cause, its symptoms, and course. The key to the spread of smallpox from 1774 to 1882 was the twelve-day incubation period, during which the carrier was highly contagious but asymptomatic. Thus, the disease was spread, particularly amid the immunologically naive Native American population, through interactions with seemingly healthy people who only got sick and died after infecting others. Emanating from the author’s well-documented and scholarly pursuit of the disease from Boston to the Pacific Northwest is the guiding principle, “Smallpox comes from where smallpox was.”

The story starts in 1775, when smallpox first erupted in British-held Boston. Due to periodically recurring episodes of “the plague” in Europe, most of the British troops had natural immunity to smallpox. By contrast, the colonial settlers who were continually besieging Boston had long been removed from Europe, and were, therefore, quite susceptible to the disease. Jenner, it will be recalled, did not elaborate a vaccine until 1796, but immunity could be attained theretofore by deliberate inoculation with smallpox itself, a practice known as “variolation.” This risky practice, the author intriguingly asserts, resulted in the inoculee typically contracting a mild form of disease, complete with the infectious phase. Many people who were inoculated to acquire immunity at the cost of contracting a milder form of the disease nevertheless spread full-blown smallpox to those who were not inoculated. There is evidence that the British used smallpox as a form of germ warfare by knowingly sending newly inoculated citizens out of Boston to infect the colonists. The Colonial troops were badly affected by smallpox at the beginning of the Revolutionary War. In a last-ditch effort to save the war, George Washington ordered that all troops at Valley Forge be inoculated, which was carried out as a secret mission, lest the British find out and attack while 75% of Washington’s army was ill.

As the war spread to the South, so did smallpox. The southern colonies had been more likely to outlaw the practice of inoculation than the northern ones, and the southern population was consequently vulnerable. Moreover, as royal loyalist landowners “liberated” slaves and servants for conscription to the British forces, the epidemic grew. It is estimated that 27,000 of the 30,000 slaves who joined the British troops died of smallpox.

The chapters of the book dealing with the spread of the disease throughout New Spain are dependent on limited documentation, such as records of the dead available from the missions, and are consequently less detailed than the chapters that cover the Colonies. The spread of smallpox in New Spain followed the silver mining trails of the camino real. One major statistic that is taken as testimony to the epidemic in New Spain is the decrease in the recorded mean age of marriage, putatively indicative of a survival strategy. A second statistic is the increase in the rate of conversion to Catholicism. Apparently, as traditional medicine and gods failed to protect disenchanted natives from smallpox, the Spanish friars, many of whom had natural immunity, became more sought-after for spiritual guidance.

I found the chapters on the spread of the disease among the Native American populations most interesting, second only to the book’s history of the Revolutionary War. Although the book intermittently threatens to digress irrevocably into discussions of trade or tribal dynamics, the author is invariably able to bring the story back to the role of smallpox. As an example, the rivalry between the Comanches and Shoshones on one hand and the Blackfeet on the other is explained in some detail: The Comanches and Shoshones are ascribed the upper hand by procuring horses from the Spanish, whereas the Blackfeet gain an advantage by obtaining guns from the French. The relevance of these dynamics finally becomes clear as horses and guns both escalate the frequency of wars (i.e., the frequency of intertribal contact) and thus facilitate the spread of smallpox.

Of all the victims of the smallpox epidemic, the impact on Native Americans is most poignant. Whole tribes died out, and the balance of power between nations was obliterated. Smallpox gave the Sioux a long-sought advantage over the Missouri River tribes, with the result that several of the latter (e.g., the Mandans) disappeared entirely. The native peoples of the Pacific Northwest were particularly hard-hit. The author carefully considers all possible sources for the spread of the smallpox among the Native Americans, and comes to the conclusion that, ironically, intertribal factors were more decisive than European-versus-native tensions per se. Ultimately, she concludes, the Shoshones transmitted the smallpox plague from their Comanche allies to the Canadian plains tribes, across the Columbia River to the Pacific Northwest tribes, and to the Eastern Plains tribes, either by warfare or by trade.

This book is not a light read—the end notes alone comprise eighty pages—but it is full of fascinating history. Elizabeth A. Fenn teaches history at George Washington University.

• © American Society for Pharmacology and Experimental Theraputics 2003

Christie Carrico, PhD, is Executive Officer of ASPET.