Disease was by far the largest killer of the Civil War, as it is with most wars. One reason disease killed so many in this war was because of the conditions of the men. The only requirements to join the army were to have all of their limbs and most of their organs. Only needed one eye. Only needed a finger and thumb on the same hand and two teeth, one on top of the other. Soldiers did need a physical exam. Clearly those were a joke, it is reported that at least 400 women passed as men. Now, I am not a medical doctor, but I am pretty sure I could at least tell the difference between a woman and a man.
Historically Speaking 