Most people understand that much of the genocide perpetuated by Caucasian settlers in the New World was unintentional — it occurred because of illnesses and disease that they brought over on their ships. Native Americans had no resistance to these illnesses. Even simple influenza — the deadliest virus in the history of the world — wiped out entire Native American tribes alongside diseases like cholera, measles, scarlet fever and even the bubonic plague that wiped out a third of the world’s population in the Middle Ages.
Most of the illnesses that wiped out the Native Americans might be considered technically pandemic. The flu, for example, spread across the globe each year much as it does today. We typically call it an epidemic whenever and wherever it occurs, but the reality is that the virus is much better categorized as a pandemic. It was the same in the centuries when Native Americans and white settlers collided.
Other cases are less obvious and difficult to track. We don’t always have access to accurate information for outbreaks that occurred centuries ago.
For those diseases that were not already considered pandemic, there were epidemics in Native American communities. This outbreaks occurred not only because Native Americans had no antibodies or natural immunities to the illnesses, but also because they treated illness very differently than the people who brought the diseases to them.
That is to say that Native Americans believed a member of society could only become seriously ill when the spirits chose not to protect him. That meant that Native Americans often applied charms meant to mitigate the damage done by illnesses.
Even these beliefs were challenged when Native Americans figured out the real problem: Caucasian settlers. When they finally understood how these diseases were transmitted, they avoided contact wherever and whenever they possibly could. This was made more difficult because settlers also understood the powerful weapon they had at their disposal — and so they used it to push Native Americans off the land they wanted.
A prime example of the use of biological warfare was the Siege of Fort Pitt in 1763. When the Native Americans mounted a failed attack on the fort, they were pushed back. Those who lived in the fort pretended to make peace with the tribe that had attacked them — when in actuality they had gifted the Native Americans items that contained the smallpox virus. This action was hardly an isolated incident.
These epidemics decimated population numbers. Before smallpox and cocoliztli, there were an estimated 22 million Native Americans living in Mexico. That was in the year 1520. By 1550, the population had fallen to about 3 million.