Lack of sewage treatment systems, lack of hygiene, poor sanitation.
Explanation:
Cholera was prevalent in the U.S. in the 1800s, before modern water and sewage treatment systems eliminated its spread by contaminated water.
Typhoid fever was prevalent during the war and was caused by poor sanitation and lack of cleanliness, eg not washing hands and clothes. It developed more slowly than cholera, but could also be fatal.
