From Lost Fables Wiki
Contracted through fluid transfer, whether ingested or injected, from an infected host.
It is infectious typically through eating the meat of a Feral or being bitten by one.
The illness naturally crops up in boars, bears, and rats at times.
About a week after infection, the subject will suddenly become ravenously hungry, seeking to near-constantly eat typically high-protein foods. Consequently, most infected will put on plenty of weight in the first four months of carrying the illness, generally between forty and one hundred kilograms, depending on how much food they can get their hands on, and how much they control themselves during the time. After about four months, they begin to develop light sensitivity, and are instinctually driven to find somewhere cool and damp to lie down at the same time that they begin to develop severe flu-like symptoms, minus the vomiting and diarrheal effects. Generally speaking the place they are driven to find must also be near a source of freshwater. Having found a place like this, the patient will enter a near-hibernation state, collapsing within the cool, dark shelter, and beginning to experience bodily changes as the virus begins to do work on the majority of the body’s cells. Generally speaking, they only rise once every several days to slake their intense thirst, before the pain of sunlight drives them back to their cave. After a solid two months in this state, their brain will have been thoroughly and permanently addled by fever, leaving only a beast driven by hunger. The body, on the other hand, will have changed to be stronger, converting the gained weight into extra muscle, denser bones, garish, cruel looking horns which extend from knees, elbows, and the crown of the skull, and a secondary row of sharper, larger teeth, or even tusks. The hunger will not have abated in this time, however, leading the beastly creature, a Feral version of whatever it was, to go out and seek ever more meat to eat.
Though it does not kill its target, most find the death of personality to be worrisome indeed.
Only a magical panacea, administered before the hibernation, can cure it.