Purple Fever

The Purple Fever is viewed by most of the population as a death sentence. An infection isn't recognized as the purple fever as first, because it's symptoms line up with a regular fever for the first few days wich makes it immensely more dangerous because it is already contagious at that point. 
After 3-4 day purple boils and lumps start to form around the neck and start to spreading all over the body at that point.  Blood and pus seeps out of these strange swellings, which are followed by a host of other unpleasant symptoms, vomiting, diarrhea, terrible aches and pains and then, in short order, death.
Currently there is no know treatment for the Purple Fever and the survival rate is almost zero, nor is the origin of it known or how to treat it. The only mutuality of it's victims is that they seem to have some sort of magical abilities.

Type

Magical