During the 1830s, diseases brought to the Great Plains region, chiefly smallpox, devastated many Plains Indian groups. This was nothing new in the cultural mingling and cultural conflicts between Native Americans and European traders/settlers. But it was one of the earliest documented pandemics in what we now call the Old West.
According to historian Paul H. Carlson in his excellent book “The Plains Indians,” this smallpox outbreak was started when deckhands in an American Fur Company steamboat moving up the Missouri River came in contact with members of several tribal groups living along the Missouri. By 1837, Carlson says, thousands of Arikara, Mandan, and Hidatsa people had died. He suggests that probably half of the Arikara and Hidatsa population of 4,500 died in this 1837 outbreak. In addition, he estimates this smallpox outbreak killed “virtually all” of the 1,600 Mandans living in the Upper Missouri region.
Diseases that came from Europeans and wiped out villages and large numbers of Native Americans were nothing new even as early as the 1830s. Historians suspect, in fact, that some of the Puritan accounts of mysteriously empty villages with full food stores which they encountered upon first landings in New England were probably empty because the inhabitants had picked up various diseases — or fled the risk of such diseases — from Portuguese explorers/fishermen who came to the area. (Some of the Puritan writers, however, credited such “miraculous” provisioning to Divine Providence making the way for their survival in the New England. But that another story for another time.)
Later history of the Old West, during what we call the Indian Wars, reveals some of the more horrible, dark side of European contact with American Indians — cases when white people intentionally infected Indian villages with smallpox and other diseases by means of abandoned blankets and clothing. But one of the earliest traceable outbreaks of smallpox among Plains Indians came from the American Fur Company boat venturing up the Missouri River in the 1830s.