Epidemics
Several smallpox epidemics have swept into, and through, the Pacific Northwest,causing devastating effects on Indigenous communities.

Populations dropped by as much as 90% in the course of just three weeks. Malnutrition and dehydration compounded mortality rates; survivors were left physically and emotionally scarred; the sudden loss of knowledge keepers left survivors confused and vulnerable.
We are still in the process of determining the exact origin/cause of each of these epidemics, as well as their full geographic extent.
Endemic Smallpox
By the late nineteenth century, a combination of steamboat and railroad transportation associated with increased settler populations, tempered by systematic vaccination efforts, transformed smallpox from a disease that arrived as periodic epidemics among virgin (unvaccinated) populations into a disease that was endemic with sporadic outbreaks that tended to be locally isolated.
“News reached [us] from the east that a great sickness was travelling over the land, a sickness that no medicine could cure, and no person could escape. Terrified, [we] held council with one another and decided to send [our] wives, with half the children, to their parents’ homes, so that every adult might die in the place where he or she was raised…Then the wind carried the smallpox sickness among [us]. Some crawled away into the woods to die; many died in their homes. Altogether about three-quarters of the [Stó:lō] perished...”