North American smallpox epidemic

The New World of the Western Hemisphere was devastated by the 1775–1782 North American smallpox epidemic. Columbus' first voyage to America can be attributed for bringing the smallpox virus to America and led to its spread across most of the continent of North America.

Smallpox is a dangerous disease caused by the variola major virus. The most common type of smallpox, ordinary, historically has devastated populations with a 30% death rate. The smallpox virus is transmittable through bodily fluids and materials contaminated with infected materials. Generally, face-to-face contact is required for an individual to contract smallpox as a result of an interaction with another human. Unlike some viruses, humans are the only carriers of variola major. This limits the chances of the virus being unknowingly spread through contact with insect or other animal populations. Persons infected with smallpox are infectious to others for about 24 days of their infection time. However, there is a period of time in which individuals are contagious but have only begun to experience minor symptoms such as fever, headaches, body aches and sometimes vomiting.

This epidemic occurred during the years of the American Revolutionary War. During this time, there was no medical technology widely available to protect soldiers from outbreaks in crowded and unhygienic troop camps. Thus, this virus posed a major threat to the success of the Continental Army, led by George Washington.

It is not known where the outbreak began, but the epidemic was not limited to the colonies on the Eastern seaboard, nor to the areas ravaged by hostilities. The outbreak spread throughout the North American continent. In 1775 it was already raging through British-occupied Boston and among the Continental Army's invasion of Canada. During Washington's siege of Boston the disease broke out among both Continental and British camps. Many escaped slaves who had fled to the British lines in the South likewise contracted smallpox and died. In the South, it reached Texas, and from 1778–1779, New Orleans was especially hard hit due to its densely populated urban area. By 1779 the disease had spread to Mexico and would cause the deaths of tens of thousands. At its end the epidemic had crossed the Great Plains, reaching as far west as the pacific coast, as far north as Alaska and as far south as Mexico, infecting virtually every part of the continent.

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