This Achievement has 3 Parts. A Sidemission and 2 Collectible Parts. (Mushrooms & Victims)
All 3 Parts are located in the Bayou Area. First of all you must complete the Sidemission called "Bayou Fever". The Mission is marked on your Map with a Skullsymbol (On my Maps Below with "M") and available later in the Game.
The Mission is easy and quick to complete. After you finish the Mission, you can now collect Mushrooms to cure the 9 Victims. (The Mission spawns both in the Bayou Area)
There are total of 10 Mushrooms and the all 10 Mushrooms are part of the
Collector Achievement, so you must collect all 10. For this Achievement here, we need only
9 of them.
To cure a Victim, you have to knock him out and then give a Mushroom to him. After the 9th Victim the Achievement pops up.
I have a lot of spoilers used here to provide a better overview, simply fold the spoiler from your currently needed.
The clickable Timeline links will open in a new window and the video will start at the time or at the Item. In the Youtube Description you have the same Timeline too. Directly on Youtube dont open a new Window when you click a Timestamp. (Works only there)
I have created own Maps for each Collectibles. The Maps are cleared of any other Symbol (except Fast Travel).
MushroomsVideo:
Timeline:
Map:
VictimsVideo:
Timeline:
Map:
Regards