During the American Civil War, it is estimated that over 600,000 soldiers were killed in battle. While many factors played a role in these deaths, disease was responsible for more casualties than any other factor combined. From 1861 to 1865, more soldiers died from sicknesses such as dysentery, typhoid fever, and malaria than from bullets or bayonets. The unsanitary conditions of camp life as well as a general lack of medical knowledge at the time exacerbated the spread of such diseases. Ultimately, disease was the greatest killer of the Civil War.
The primary cause of disease-related fatalities during the Civil War was the lack of knowledge about hygiene and sanitation. Many soldiers, especially those from rural areas, had limited understanding of proper hygiene under such conditions. The close living quarters combined with poor waste management and standing water made it easy for diseases such as dysentery to spread quickly through an entire encampment.
Additionally, the medical tools and treatments available at the time were limited and often ineffective in preventing further spread of infection. There were also shortages in basic medical supplies due to the difficulties of resupplying armies in battle. This all led to a high rate of illness among both Union and Confederate soldiers, resulting in thousands upon thousands of avoidable deaths.