[13lackGu4rd]

undeads get diseased but it actually does nothing to them, as undeads are already dead to begin with... so don't worry about the lose 1hp/turn until death from disease. however other afflictions do affect your undeads just like normal troops, which is why Gift of Health(enchantment6 nature global) and The Chalice(artifact) are very sought after, as most nations use Tartarians(from the conjuration9 D7 spell Tartarian Gate) and these have a tendency to arrive with afflictions, most annoying ones being feeblemind, blind and mute.