From Lost Fables Wiki
Living in cold climates for extended periods of time allows this natural gut bacteria to prosper far beyond its normal limits.
It is non-infectious.
All Oe Il’ha carry some of the bacteria in their stomach fauna.
After consistently (more than 8 hours a day) spending several weeks in temperatures below 23 degrees celsius (75 degrees fahrenheit,) Oe are likely to contract this illness, an imbalance of stomach bacteria, and grow more likely each day. Once contracted, the patient will begin to experience cold chills along with a degree or more of core temperature cooling. After only a day or two of this, they will begin to suffer from fatigue, only minor at first, though if left untreated, it can grow quite bad, leaving the subject with little to no energy to even move out of bed after almost a full month. At some point during this time, the patient develops agoraphobia as well, causing them to strongly fear the outdoors.
Though non-deadly, the agoraphobia one develops can last the remainder of an Oe’s life, while the cold chills (and their accompanying shivers,) can make it impossible to get anything done, especially when taken in concert with the extreme fatigue it causes.
Though merely staying in a place at least 75 degrees for a full three days will cure it, eating very spicy foods can cut this time down to only a day, and the capsaicin within will put off the time it takes for the disease to set in by a day. For this reason, many Oe enjoy drinking spiced coffee or bloody marys with their breakfast, a delicacy in their eyes, though most other species find both of these to be somewhat distasteful.