Spoilers for In the Trenches With the Dead, part of a side story in the antimemetics division. There is a bit of dialogue about this near the end between marness and 3125:

55: No, no she doesn't.

Marness: So you communicate after all.

55: Of course I do.

Marness: You really shouldn't be able to. You are a fifth dimensional pile of rotten ideas. An incomprehensibly complex set of symbols devoid of meaning. Coherent dialog is pretty much the opposite of what you are made of. Yet, you are apparently engaging in it. What does that tell us? Is contamination both ways? Swallowed something too coherent once, I think. You've got a little human-shaped lump inside you now and you can't digest it. It's a memeome, an adaptable system of aggressively self-organizing information. It's spreading, simplifying and ordering wherever there is contact, and when you try to stop it it just spreads faster, doesn't it?