From Lost Fables Wiki
A natural bacteria part of fae gut fauna.
Consuming contaminated water or meat. Wash your hands!
Most fae creatures carry it as part of their stomach fauna
About eight hours after consuming contaminated food, this disease causes the symptoms of food poisoning, typically with uncontrollable vomiting and diarrhea for between twelve and forty-eight hours after symptoms appear. This can be deadly, if the patient doesn’t drink plenty of water, but the true, more insidious effect of the illness starts only a good deal after this initial, very obvious sickness. Generally speaking, between two weeks and a month after the bout with food poisoning, hallucinations will begin inside the mind of the Il’ha, starting as auditory hallucinations, usually like an odd chiming in the distance, but progressing rapidly after a few days into fleeting visual hallucinations. Generally, these hallucinations begin as taking the form of something rather innocuous, many report seeing bell fairies for this portion of the sickness. After a week or so of these rather innocuous hallucinations, they generally take a turn for the sinister, with the Il’ha’s perception of distance starting to shift, their perception of the lines in an object beginning to blur and meld, and the visual and auditory hallucinations slowly spiral downwards into a waking nightmare, which follows the unfortunate Il’ha into their sleep. At this stage, the Il’ha typically act extremely erratically, frequently becoming aggressive and violent towards a world around them that they cannot possibly make sense of, and it is during this stage when the disease is most deadly, as an Il’ha can neglect to eat or drink in this stage, usually out of pure horror. Generally, only Il’ha with strong family or support structures survive the disease for this reason. This final stage usually lasts for between one and two months, after which the Il’ha will generally defeat it. Most find themselves somewhat traumatized by the experience.
It won’t kill on its own, but without a support system, you’ll die.
Magical Panaceas are the only cure, other than letting it run its course.