When I saw the subject line of your posting, I checked the roster of the 28th Texas Cavalry and found no Wade Hampton Walters listed. I thought I should write and make sure that you realize that he served in the 17th Texas Cavalry rather than the 28th Texas Cavalry. I agree with Gary Bray that your ancestor probably died of measles or one of the other common "camp diseases" of the time. In the 28th Texas, 78 men died during the fall of 1862, most at Camp Nelson. The 17th Texas Cavalry may have had a similar death rate.