SureAI

What a lovely name!
So, it looks like it's only restricted to the Undercity?
I doubt that we'll get anything more about it, but I wanted to make some theories about its implications. We see the afflicted suffering in the Undercity's streets and corners, in varying states of health, until you push deeper underground and find the area where their bodies are dumped. No safe zone, no quarantine, no biohazard signs. As far as I'm aware it hasn't spread to the surface, but how does it spread, anyway? Is it opportunistic? Or is it like the Red Madness? With like, three guards around the main underground entrance and another unguarded entrance out into the Noble's quarter... there should be at least some victims up top if it were really virulent.
It seems more the former since the citizens of the Undercity are very vulnerable. For the most part, they're already in worse health than surfacers. Would the Apothecarii currently treating the sick fall ill too, or would they be protected by their stronger immune systems?

The cure itself is a little depressing (not in the sense that it's ill thought out; more out of sympathy for those that have to take it). Really, both red and green Vynroots are poison; you're giving it to the sick hoping that the fleshmaggots will all die before their bodies give out. The Vynroot is definitely prepared differently by alchemists than assassins; but I doubt the Apothecarii managed to isolate a compound in the red Vynroot that's specific to fleshmaggots. There might be a higher survival rate if the person undergoing treatment was healthier, but if they were, they probably wouldn't have the plague in the first place.

Surface people could get fleshmaggot too, there is a quest from the Ironford family (foreign quarter) where their daughter died of fleshmaggot.

That's how chemotherapy works too, buddy.

Fleshmaggot analogy with real life cancer? There's one thing missing which is the good, the rich, and the noble get cancer too.

iirc, there was a fleshmaggot plague not too long before the story takes place. killed lot of folks, rich ones too. that "other" novice you meet during your keeper rite thingy (the annoying angry guy), lost his whole family to it. so it doesn't just kill the poor.

You made a good point.