From Lost Fables Wiki
Typically found in stone, sometimes in worked stone, meaning they can originate both in caves and in the paved stonework of cities.
Can spread from Ue to Ue after sustained close contact, or from stones or stonework if the Ue comes into contact with a large colony of the mites, which look very much like grout and cluster in the grooves between stones.
Only Ue are susceptible, and Ue miners far and above are the most likely to contract it. Drachev sometimes have the mites in their hair or on their clothes without noticing, otherwise the stone itself is a carrier.
Even when an Ue comes into contact with the mites, it is not enough for them to merely come into contact with a few, a whole colony must be disturbed, usually of thousands of the infernal little insects. Generally speaking this presents as a whole cloud of stone dust, which will fling themselves at a creature if one touches a small part of the colony. While for most creatures this is merely an itchy nuisance, able to be taken care of with a clean whole-body shave and a long bath, it is much worse for the Ue, if left to fester. Within the first thirty hours, they are just an itchy nuisance, just like anyone else, however, if they are left to feed on the Ue for much longer than this, the Ue will suddenly find their connection to nature and one another abruptly and painfully severed, leading to the eventual feral madness any Ue suffers when cut off from nature if not dealt with, as well as (generally) extreme mental anguish.
Though the parasites themselves do not kill, the side effect absolutely will.
Shaving all one’s hair and taking a long, hot bath with harsh soap will cure one of the mites themselves, however only a specific set of Truths or a magical panacea will cure the Excommunicatory effect.