Bryan covered the topic pretty well, but I wanted to see sure you understood that the wounded would have all been sent to an 'interior' hospital or furloughed home within a month or so of the battle. Due to the conditions Bryan mentioned, diseases took an even heavier toll of men who survived the battle or who entered camp at Corinth afterwards. Based on contemporary accounts, Confederate medical resources couldn't handle the situation and were simply overwhelmed by the sheer number of soldiers needing treatment. Records-keeping for thousands of the sick and wounded suffered as a result.