Did Europeans deliberately give smallpox-infected blankets to Native Americans? Absolutely. There is one proven case and many other suspicious ones. But the largest smallpox outbreak, the one that killed possibly hundreds of thousands of Natives, started during the Revolutionary War. While the war naturally brought people – and the virus – together and then re-distributed them, the virus was also spread when the British army, most of whom had already been exposed to the disease, deliberately tried to infect American colonists with smallpox.

Inoculation and Biological Warfare

They didn’t use blankets; they used each other. Enter Onesimus, an African slave of the Puritan minister Cotton Mather, who taught the colonists sixty years earlier how to inoculate people against smallpox. This practice emanated from Africa and was unknown to Europeans. Inoculation, or variolation, is not quite the same as a vaccination. The skin of a healthy person is deliberately slit and infected with a scab from a smallpox victim. The result is a mild form of the illness, usually not fatal, resulting in lifelong immunity. But the infected person is temporarily contagious, able to pass on the full-fledged form of the disease. This made inoculation controversial; it was banned in some colonies and Mather’s house was burned by an angry crowd when he promoted the practice.

During the Revolutionary War, when under siege in Boston in 1775, the British weaponized their prisoners, inoculating and releasing them. This, along with the comings and goings of the war, led to the largest single smallpox outbreak in North America.

Smallpox and war often went together, either thru deliberate or accidental contamination.

At first, American colonists were skeptical that the British would do this to other white people. But General George Washington became suspicious. He wrote to John Hancock, “The information I received that the enemy intended Spreading the Small pox amongst us, I could not Suppose them Capable of – I now must give Some Credit to it, as it has made its appearance in Severall of those who Last Came out of Boston.”

The Great Smallpox Epidemic of 1775-82

This interactive map documents every likely case of smallpox during the 1775-82 epidemic.

The virus spread with the war. It killed 500 American troops outside Quebec, thus preserving Canada as British territory. After that, George Washington secretly inoculated and quarantined his own troops; he viewed this as a critical strategy to win the war. In Virginia, where the British offered freedom to 30,000 escaped African slaves, 90% of the so-called Ethiopian Regiment was wiped out by smallpox. It then spread thru trade and war to the Creek in Pensacola, to the Cherokee on the Holston River, and to the Ojibwe in the Great Lakes.

In August 1779, smallpox appeared in Mexico City, possibly arriving from Spanish-controlled New Orleans. From there, the virus raced up the El Camino Real to Santa Fe, infecting the Pueblo and Hopi. After that, it outpaced European colonists, spreading thru Native trade networks to regions never before exposed to the virus. It passed from the Comanche up the east slope of the Rockies to the Shoshone. On the Great Plains, it especially struck the sedentary farming villages of the Arikara, Mandan, and Osage. Where there were thirty villages before the plague, there are two afterwards. The nomadic Sioux fared better.

A depiction from a Sioux winter count blanket for 1780-81.

From the Shoshone, the virus spread north to the Blackfeet and Cree all the way to Hudson Bay. It also jumped the Continental Divide, struck the Nez Perce, and spread down the Columbia River to the Pacific Northwest. Ten years later, when Captain George Vancouver arrived in Puget Sound, he encountered as many abandoned villages as occupied and described an apparent depopulation. Former villages were overrun with weeds; survivors were pockmarked and sometimes blind in one eye.

Most accounts describe an infection rate exceeding 50%, and a mortality rate, for those infected, approaching 90%. This was largely due to poor care for victims. In regions where no one had immunity from prior exposure, care-givers either became sick or fled. Total population loss for the hardest hit areas often exceeded 60%.

Viruses and indigenous peoples

But that wasn’t the only smallpox epidemic; there were many smaller outbreaks—some before, some after. The common refrain that imported viruses wiped out 90% of the indigenous people of the Americas is probably an exaggeration. At the very least, it did not happen all at once. It did happen in isolated instances—such as at Pawtuxet in 1620, allowing the Pilgrims to establish Plymouth. But most epidemics hopped and skipped thru the land at intervals since the 1500s, missing some areas while conferring immunity to survivors. Additionally, sometimes Native populations rebounded between epidemics. Nevertheless, a massive depopulation of North America did occur at the same time that Native tribes in the US lost their British, French, and Spanish allies. Tribes after the Revolutionary War were left alone, short-handed, to face the new and aggressively expanding United States of America.

Smallpox blankets

The only well-documented instance of Europeans deliberately attempting to infect Native Americans with smallpox occurred in 1763 at Fort Pitt, Pennsylvania. English General Jeffrey Amherst recommended it: “Could it not be contrived to send the smallpox among the disaffected tribes of Indians? We must on this occasion use every stratagem in our power to reduce them.” (He now has a town and a prestigious college named after him.)

Colonel Henry Bouquet agreed to implement the plan: “I will try to inoculate the bastards with some blankets that may fall into their hands.”

But, unbeknownst to them, the garrison at Fort Pitt had already done it on their own. A diary written the same day as Amherst’s letter (and well before it would have been received) said: “We gave them two Blankets and an Handkerchief out of the Small Pox Hospital. I hope it will have the desired effect.” Ecuyer later submitted an invoice stating, “taken from people in the Hospital to Convey Smallpox to the Indians viz; 2 Blankets, 1 Silk Handkerchief.” He wanted to be reimbursed!

The fact that both Amherst and the men at Fort Pitt thought of it independently, and that Bouquet quickly agreed to the plan, suggests that it was a practice all were familiar and comfortable with; it was “a thing”.

In addition to this incident, there are many more stories from tribes who have similar suspicions. By the 1800s, the smallpox vaccination had been created and supplied to many white people in the East. However, Natives were largely unvaccinated and vulnerable.

In 1865, a newspaper in the Sacramento Valley asserted that “the [white] people are enraged against them, and are ready to knife them, shoot them, or inoculate them with smallpox – all of which have been done.”

Recommended reading: Fenn, EA. 2001. Pox Americana: The great smallpox epidemic of 1775-82.