I believe the CNN news story was of a child who survived rabies
after showing symptoms of the disease, but with extremely intensive treatment after she showed symptoms (she was bitten by a bat, but her parents didn't think that was a problem). It made the news because it's the second time in recorded history that a person who's shown symptoms of rabies has survived: in the first case, the afflicted child never arose from a coma.
Give the disease an incubation period of 1d3 weeks (there are cases that happen faster or slower, but these are outliers; most cases happen fairly quickly). A DC 20 initial fort save is appropriate, but if you want to model it appropriately, there should be no later saves: in a human population, rabies is 100% fatal without treatment, and 99.9% fatal with treatment.
You might allow a DC50 heal check (or higher) to cure the disease; otherwise, I would allow only a magical cure to work.
In addition to the slow wisdom and con damage (the wisdom damage should be faster, since it's a neurological disorder, and patients usually lapse into a coma before death), consider applying something similar to the effects of a Confusion spell once the patient's wisdom drops to 3 or less: at random times, the patient has a 50% chance to become very fearful, a 25% chance to become very aggressive and attack living creatures with bites and claws, and a 25% chance to fall down (rabies often diminishes the ability to balance).
Daniel
Humane Educator in real life