StrategyPage has a review of a recent book about non combat deaths in the US Civil war....
Willis opens by pointing out that for both sides taken together, combat deaths amounted to perhaps a third of all deaths. He then sets out to explain how the other two-thirds perished.
Naturally disease was by far the biggest killer, causing most of the non-combat deaths, particularly early in the war as volunteers flocked to improvised training camps.
Mostly men of rural origins – even most Northerners – the recruits usually lacked immunity to many commonplace diseases, and died in droves. Dysentery was apparently the biggest killer, acquired from bad food or water, but malaria and pneumonia were up there as well.
Wills also looks at other causes, which seem to have accounted for about a tenth of all deaths. Accidents ranged from drowning to weapons malfunction or misuse, lightning strikes, sun stroke, falls, even snake bites. And there were also some murders, suicides, deaths in duels, executions, and others.CSPAN has a discussion here. (R rated)
The Swamp Doctor's adventures in the southwest ebook
Reminiscences of a Southern Hospital, by Its Matron