• Long-Term Chronic, Majorly Debilitating: These diseases cause constant irritation and exhaustion and eventually end in death. Leprosy, untreated tuberculosis, and similar fatal diseases fall into this category. Victims have frequent spasms and coughing fits and so are always Exhausted. If they suffer an additional Fatigue level, they are Incapacitated but do not die. At the start of every game session, the character must make a Vigor roll. If his total is ever a 1 or less, he’s going to pass away before the end of that session. The Game Master is encouraged to let the hero go out with style if possible, but he will perish before the game ends this time.
• Long-Term Chronic, Minorly Debilitating: This works exactly as above except the unfortunate hero is constantly Fatigued rather than Exhausted. Examples of this kind of disease include malaria, fantasy diseases such as the touch of certain undead, or living in a foreign and slightly toxic environment.
• Short Term, Debilitating: These are extremely rare in the real world but are very appropriate for fantasy or science-fiction settings. They are typically acquired from the scratch of a creature or breathing air laden with toxins (see Airborne and Induction, above). A victim who fails his Vigor roll and contracts the disease suffers Fatigue and is Shaken as he begins to cough and wretch uncontrollably. Once he recovers from being Shaken he may act normally but the Fatigue level (and thus the disease) remains for 2d6 days while the sickness works itself out.
• Short Term, Lethal: Even more rare are diseases that can kill in seconds. Treat this exactly as Lethal Poison (see Poison). If a character survives but suffers Fatigue from the poison, it lasts 2d6 hours.

Savage Worlds Deluxe Edition p. 100