Some of the information in the first link is wrong the highest death rate amoung northern prisons was Elmira,N.Y..I don't believe that can be argued. Camp Douglas is second.I might ask before anyone judges that you study civil war prisons as a whole.Both sides.Read Portals of Hell,Military Prisons of the Civil War,Speers. While pure hell was inflicted some of the reasons for the condition have to do with the logistics of the situation.Captured prisoners were dressed as they had been taken from the field(some after days of fighting) and spent days in transet wet and bloody without shoes,coats or blankets with little food. Poor planning,sanitation issues concerning large concentrations of people,diaria, including diseases such as smallpox,etc.,lack of medical knowledge/ability in general.Sure dishonest people siezed oppertunatey and preyed on the prisoners.We have that today in general society. I will admit that after Nov. of 1864 it was federal policy to extract revenge on prisoners held and Camp Sumpter(Andersonville)Sept.64 was formed to help allieviate conditions in Richmond.Bad and good neither policy turned out any good.
I was born in IL. just west of Chicago. My GGUncles were gaurds(127IL.Inf.) at Camp Douglas for a period fall 1862,spring 1863.Camp Douglas was first a muster, training camp.Several of my relatives went through Camp Douglas for training. Many of the gaurds were new regiments not yet sent to the field.While a parole camp(Federal soldiers awaiting exchange)they burned the camp.I say that because condition for their own men were not much better.There is a politics of the situation for sure.The weather played a large part, I have seen thirty below for daysas a child, but, then again the extreme heat and humidity( I now live in Texas where sometimes it doesn't even drop past eighty at night then 100's and 98%humidity day after day) caused suffering to northern prisoners in southern camps both are extreme hardships.
My maternal GGGrandfather was held at Elmira from May of 1864 to April 1865 captured three times served over 18months in various Federal prisons.A devote catholic claimed he only survived because of the grace of God and the power of prayer.Not bitter he took the oath of alligiance in Apr.65 was released and never returned south.An Irishman he became a citizen in 1866.Death Camp of the North(I'm sorry I can't remember the author)
As well my paternal GGGrandfather served in southern prison captured at Murfreesboro,TN.Dec.31,1862.He spoke of the condition at the time but,wasn't bitter.It was war...
Read O.R.Series II Corespondence concerning Prisoners of War and State.
http://cdl.library.cornell.edu/moa/browse.monographs/waro.html
I would be glad to recommend books on the subject if interested.Post on Prisons site Hugh Simmons is not only a southern gentlemen but, a scholar on the subject.