Water in rivers, ponds, lakes, and the like are far from pristine. Animals live, die, drink, bathe, and excrete in and around them all the time. This is on top of the thousands of other settlers traveling along the same route also contaminating water sources.

The Oregon trail usage is mostly 1849-1860. The estimated number of travelers is 296,000 for that period or on average 26,900 per year. If they are equally spread out during the whole year that is 74 people per day. In really travel will happen during the warmer months and most will start during a short period of the year, the journey takes around six months.

The estimation of the death rate because of disease is 2-4%, and the total death rate is 3-6%

So a single point along the trail likely has over 100 people passing per day, They will use wagons that animals pull to. There will be a lot of litrera shit around the trail, there is likely no organized way it was handled at all like in a place where you live for a longer period of time


The germ theory of disease is not the accepted explanation for diseases. The common explanation was particles in the air refed to "miasma"

The 1854 Broad Street cholera outbreak is well-known because the physician John Snow studied it to show that cholera was the result of germ-contaminated water. He created a map of where the 616 people that died lived and come to the conclusion that it was a water pump they used that as was the cause of that cluster.

It is not until 1861 that Louis Pasteur presents experimental evidence for germs. It took a long time before most people learned about it and started to know what it needed to prevent outbreaks. I would say for unorganized events like the Oregon Trail was people still do not do it.


So the people back then on the Oregon Trail and in other locations would not have taken the appropriate precaution because they did not know the source of the disease. One problem was that people were often buried at the site of their death. A lot of deaths is likely in appropriate location to set up camp, that is location with access to water that could be contaminated by the buried bodies.

The Oregon trail was not just setting out alone or with a couple other people and traveling completely alone for thousands of miles till you reached the end. Long stretches of the trail like mountain passes were traversed only in small groups but there were many way-points along the way. Towns and camps for various things like mining were stopped at whenever available and may not have had great sanitation (because *nothing* had great sanitation). Portions of the trail were controlled by people that owned the land the trail was on and would charge tolls to travel along it (some of these tolls were unavoidable, but others were avoidable if you traveled less favorable and harder routes) so there was lots of opportunity for contact with other people and therefore opportunity to pick up diseases. Additionally trips were generally undertaken alongside livestock and livestock and their feces can carry a *lot* of diseases that can spread to humans when in close contact with them or their feces especially with no access to sanitation.

Dysentery is the name for the cluster of symptoms caused by a bacterial infection of the gut, what specific bacteria someone is infected with can vary a lot. Some of these bacteria are carried by cattle, some by dogs, some by wild animals. Many of these bacteria can live for extended times in soil and water contaminated with them. This is why it’s *never* advisable to drink untreated water no matter how remote the area you’re in is. You can still get diseases that will cause you to shit yourself to death even if you’re the first human to ever set foot there.