The hygiene of the camps was poor, especially at the beginning of the war when men who had seldom been far from home were brought together for training with thousands of strangers. First came epidemics of the childhood diseases of chicken pox, mumps, whooping cough, and, especially, measles. Operations in the South meant a dangerous and new disease environment, bringing diarrhea, dysentery, typhoid fever, and malaria. There were no antibiotics, so the surgeons prescribed coffee, whiskey, and quinine. Harsh weather; bad water; inadequate shelter in winter quarters; poor policing of camps; and dirty camp hospitals took their toll.[4] This was a common scenario in wars from time immemorial, and conditions faced by the Confederate army were even worse.
http://en.wikipedia.org/wiki/Medicine_in_the_American_Civil_War

What is suprising to this medical layman is the fact that good old country boys, raised outdoors in a healthy climiate, sucumbed to camp diseases much more readily than those raised in cities, exposed all their lifes to disease and subsequently immune.

Thomas Covington died in Leesburg, not Lynchburg. His brother, cousin, kin, James died there also, and is buried in the Union Cemetery there. I would assume that Thomas rests there also, his marker long destroyed before record keeping.

There is also, an outside chance, that this early in the war, he may have been among those who died at Manassas reburied in the Hollywood Cemetery at Richmond. Also, the Stonewall cemetry, Winchester.

Coviington, James W., Private, 13th Inf., Co. C, enlisted 5/14/1861 at Corinth, born c1833, died 10/14/1861 in a Leesburg Hospital of "remitten fever"
Mississippi Soldiers Buried in Union Cemetery, Leesburg, VA
http://www.rootsweb.ancestry.com/~mscivilw/unioncemetery.htm

James W. Covington, Private, Capt. Wm. J. Eckford's Company (Wayne Rifles), 13th Regiment Mississippi Volunteers,* enlisted May 14, 1861 at Corinth for 12 months, present at the Battle of Manassas, July 21, 1861, died October 14, 1861, General Hospital (also known as the 7th Brigade Hospital), Leesburg, Va., Remitten Fever (Maleria), description on enlistment: 21 year old Farmer, born Wayne County, Miss., 5' 11", fair complexion, blue eyes, red hair

* (Old) Company C

M269: Compiled Service Records of Confederate Soldiers Who Served in Organizations from the State of Mississippi