Casting Tainted Flesh on someone who is already diseased will cure them of it.
In PvE scenarios, this skill can be incredibly useful since the enemy groups you meet will often be of the same species. Attract the aggro of enemy warriors so that they may catch the condition and pass it on to the rest.
As disease is spread among a type of foe disregarding its party, the "tainted caster" has to rapidly cast it all over his team when fighting human enemies. Otherwise, targets infected by your melee attacker will spread the disease among untainted team mates.
A party of eight can be enchanted in 14 seconds, due to aftercast, and with the use of an upgraded weapon of enchanting, Tainted Flesh can last 55s with 16 ranks in Death Magic.
Be careful when using Tainted Flesh against human foes, as disease is a double-edged sword, and an incomplete casting or other anomaly like Diversion will often result in negatively affecting your team.
A Hero equipped with this spell will attempt to maintain it on all party members at all times, even out of battle.