1775 – 82 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 this virus to America and led to its spread across most of the continent of North America . The epidemic occurred during the years of the American Revolutionary War ( 1775 – 1782 ) . At the time limited medicinal options existed to help stop the transmission , and therefore the fatalities from the smallpox epidemic were as common as those from the battles of the Revolutionary War . The article , “ A Deadly Scourge : Smallpox During the Revolutionary War ” states “ During the Revolutionary War , one of the greatest threats to the Army came not from enemy bullets , but from [ the smallpox ] disease ” ( armyheritage . org ) . 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 Plain , 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 . One of the worst tragedies of the pandemic was the massive toll it took on the indigenous population of the Americas . “ The spread of smallpox also affected civilians and Native American Indians . The tragic results of smallpox … continued into the 19th century . ” ( Savas and Dameron ) . The disease was likely spread via the travels of the Shoshone Indian tribes . Beginning in 1780 it had reached the Pueblos of the territory comprising present day New Mexico . It also showed up in the interior trading posts of the Hudson ' s Bay Company in 1782 . It affected nearly every tribe on the continent , including the northwestern coast . It is estimated to have killed nearly 11 , 000 Native Americans in the Western area of present - day Washington , reducing the population from 37 , 000 to 26 , 000 in just seven years . Smallpox is a highly contagious disease that is caused by a virus that can be fatal to young children and young adults . There are two stages of the smallpox virus , the Variola Major and the Variola Minor . The article “ Smallpox ” , states that “ [ the ] Variola major is a serious illness that can be life threatening in people who have not been vaccinated . [ The ] Variola minor is a milder infection that rarely causes death ” ( Damon ) . The disease has been found all over the world . Smallpox can be spread by saliva , but it can also remain virile on bed sheets , or even clothing . This quality allows smallpox to very easily spread to relatives , especially in the close - knit communities of the American - Indians . In the Americas , efforts were made to control smallpox during the Revolutionary War . George Washington , at the time the leader of the Continental Army , chose to take some calculated risks . One method he used was to avoid the disease through quarantine . If any of his soldiers caught the disease , the exposed soldiers were removed from duty and sent to an isolated hospital designated for those with small pox . The other method , which was many times more dangerous yet more effective , was to use the process of inoculation . The process of inoculation involves exposing people to the disease , hoping that the exposed do not die . If the exposed lived , which many of them did , they would most likely be immune to the virus . It was a very effective way to slow down the disease , however , it still caused problems for the army that are best stated in the web article , “ A Deadly Scourge : Smallpox During the Revolutionary War . ” “ The inoculated would be unfit for weeks , and if the British attacked , the army could be destroyed ” ( armyheritage . org ) . It turned out to be the right choice . Washington also suspected that the British were using the smallpox disease as a form of " biological warfare " by placing disease infested people into the American encampment . Smallpox was considered more of threat to the Americans . The British admitted that their commanders ordered the smallpox operations . ( Savas and Dameron ) .