A review of the disease rules in JTAS #13 (pp.33-36):
These rules begin by suggesting that a character should roll once per month to see if he got infected by anything (with DMs for TL, innoculation, atmosphere and low END). I don't really like the idea that characters are going to be infected randomly by visiting worlds (unless they're visiting an infected area, or come in touch with contaminated people). I don't like this for the same reason I don't require task throws for ship takeoff or landing under normal conditions - only under hazardous conditions. getting sick by random is realistic, but not that fun from a gameplay perspective - risking infection to sell supplies to a quarantined plagued world is, on the othr hand, quite fun (or atleast heroic).
Next, the rules allow for the detaild generation of diseases. Each disease has a body part it effects (mostly for flavor) and a level of severity. Disease causes damage to all physical characteristics - mild illnesses cause 1D damage to each characteristic, moderate causes 2D, severe causes 3D and catastorpic causes 4D. If one characteristic is reduced to zero, the character is disabled. If two characteristics are reduced to zero, the character is in a coma. If all three are reduced to zero, the character dies after 1-6 days.
Treatment under the JTAS rules deals mostly with recovery time; characters with no or one characteristics reduced to zero could recover on their own (though medical care reduces the recovery time); characters with two or more characteristics reduced to zero require medical attention. However, "medical attention" under these rules requires no roll, just the presence and attention of someone with a Medical skill (and, in most cases, a hospital).
The artile ends in the discussion of a few medications (nothing too science-fictionish) and of medical costs.