One of the most dangerous diseases for the camps prisoners was depression. Many suffered from this because of the mental toll that being contained in the camps had on them. Starvation and poor sanitation inflamed outbreaks of diseases such as smallpox, malaria and cholera. If sores were left untreated they would have to be amputated...clearly causing more mental anxiety. The horrible conditions of the camps are thought to be worse then those on the battlefield.
Overcrowding was common and there was a major lack of sewer and sanitation. These factors caused disease-ridden camps that spread filth. The meager provisions that the prisoners were given, lacked vegetables and fruit and often lead to outbreaks of scurvy and other diseases. Sometimes, they got so hungry, inmates were forced to hunt rats to find something to eat. The hundreds of thousands of men imprisoned were too much for the camps to handle and lead to oppressive conditons.
Sources:
1) http://news.nationalgeographic.com/news/2003/07/0701_030701_civilwarprisons.html
2) http://www.spingola.com/CivilWarCamps.html
3)http://www.civilwar.org/education/history/warfare-and-logistics/warfare/andersonville.html