You are deathly afraid of infection, or just of dirt and filth. Make a self-control roll when you must do something that might get you dirty. Roll at -5 to eat any unaccustomed food. You should act as “finicky” as possible.
Make a self-control roll at the end of any battle. If you fail, roll 3d, add the amount by which you failed your self-control roll, and look up the result on the Fright Check Table.