they can be dead, though more often they are corrupted. the Wyrm (the primary antagonist force), is the manifestation of chaos/destruction. normally it's just doing it's thing in balance with everything else in creation, basically just being Entropy, not evil or good, just a fact of creation. But the Weaver, the manifestation of order/stability, went mad, growing tired of seeing all her systems eventually breaking down. So she bound the Wyrm in webs (the Weaver is a spider), and trapped him. Trapping him, drove him insane, so now he lashes out, intent to destroy all of creation, to try and break free. So his influence, is now more like mutations, corruption, etc. Think Dark Side influence on people/creatures from Star Wars, but way more body horror and grotesque, because World of Darkness.
Spiritually dead zones do exist, but they are sort of just, a byproduct of all the crazy shit. I don't recall those being directly due to Wyrm influence, and were more of a side thing in the various books. Areas that the Wyrm has had influence in, either directly or via his servants, is basically a corrupted hellscape. Horrific reflections of the normal spirits that would naturally be there. Hollow eyed humans, looking like drug addicts (even if they aren't), shuffling in fear from building to building, in neighborhoods filled with corruption. If it's a wilderness area, it will be corrupted animal/nature spirits, pollution, decay, etc.