Cholera outbreaks and pandemics
That year, cholera was transmitted along the California, Mormon and Oregon Trails as 6,000 to 12,000 are believed to have died on their way to the California Gold Rush, Utah and Oregon in the cholera years of 1849–1855. It is believed more than 150,000 Americans died during the two pandemics between 1832 and 1849.
California Trail
The route West was arduous and filled with many dangers, but the number of deaths on the trail is not known with any precision, and there are only wildly varying estimates. The estimates are made even harder by the common practice then of burying people in unmarked graves that were intentionally disguised to avoid them being dug up by animals or Indians. Graves were often put in the middle of a trail and then run over by their livestock to make them difficult to find. Diseases like cholera were the main killer of trail travelers with up to 3% (or more) of all travelers (6,000 to 12,000+ total) dying of cholera in the cholera years of 1849 to 1855. Indian attacks were probably the second leading cause of death with about 500 to 1,000 being killed from 1841 to 1870. Other common causes of death included: freezing to death (300–500), drowning in river crossings (200–500), getting run over by wagons (200–500), and accidental gun deaths (200–500).