Infectious disease
In addition to the physical dangers of the world, characters are often accosted by the sniffles and other common ailments. When it comes to sickness and plague, running out of tissues is the least of your worries.
Creatures exposed to an invading pathogen must make a Vitality check to avoid infection. The DL for this check depends on the virulence of the infectious agent. A creature who fails the Vitality check contracts an Illness.
An infected creature is allowed to make an additional Vitality check each time it awakes from a night of rest. A successful check removes one stage of the Knockout Track penalties imposed by the Illness. A Critical Failure worsens the Knockout Track penalties by one stage. Once all Knockout Track penalties are removed, the creature makes a full recovery.
Rare diseases might only be curable with medicine, if a cure is even possible.