Diseased Undead?

[Illuminated One]

So I noticed that undead could get diseased. Does this apply to sites only?
Also what is the effect? I suppose they don't die, but do they get afflictions?

[rdonj]

Disease does nothing to the undead. They regain health as normal, are not afflicted with additional afflictions, etc.

[Quitti]

Also, items can disease undead, but like rdonj said, it doesn't have any effect on them.

[Thanatus del Dragos]

Undead that spread disease can give themselves disease. But, like what is said above, I don't think they suffer any effects from it.