Disease could kill them
The U.S. National Park Service estimates that “of the 350,000 who started the journey, disease may have claimed as many as 30,000 victims.” This made disease the number one killer on the Oregon Trail. Medical aid on the trail was limited to what could be carried in wagons and whether the party had a doctor among their numbers. Parties could lose members from cholera, a disease that could kill its victim within twelve hours of its first symptom. Measles was particularly bad among children in wagon trains. Some parties suffered scurvy, smallpox, pneumonia, typhoid fever, colds, and food poisoning thanks to the less than sanitary conditions they endured. And, of course, there was always the threat of dysentery, which wasn’t always fatal, but common and very uncomfortable.