Ripped from my personal headlines…
You have been cursed to constantly suffer sickness with no explanation. This curse scales in danger based on the CR of the encounter that afflicted you. Any effort to identify this as a curse must first overcome a caster level check equal to the curse’s save DC.
Type curse; Save Fortitude (DC 10 + CR)
Onset 2d10 days; Frequency 1/day when not already ill.
Effect Any day when you are not ill (or undergoing the onset time of a disease), you must make a successful DC 10 Fortitude save against a random disease. There is a 50% chance this is a disease you have already suffered as a result of this illness, otherwise the disease is entirely random (but among those diseases you could have theoretically been exposed to). The disease always has the longest onset time and does minimum damage for a disease of its type. The disease otherwise operates normally.