Bayou Fever Trophy in Assassin's Creed III: Liberation
Complete every Bayou Fever mission
How to unlock Bayou Fever
You'll have to start the De Bayou Fever sidequest, which the 'witch doctor' near the middle of the map will give you. (skull icon) After doing his small tutorial mission, you'll have to find mushrooms in De Bayou and help random strangers who have fever. Mushrooms are hidden all over the zone and can be seen by the white glow, the same glow as the statuettes, diary pages etc. To apply the mushroom, first knockout the patient and then press
The collectibles guide has every mission and each mushroom listed.