How Would Magic Change The Economics Of A Medieval Society If Those Who Had Magic Had A 40% Disease Rate?

Some general magic rules. Magic requires believing in it. Most people can only do 3 things with it: changing the color of objects, levitating objects, telekinetic blasts. A small minority can do more, and an even smaller minority can do things that aren't on the above list. Magic costs calories to do, and the more you do the more calories it costs. For instance, levitating a pea is 1 calorie, but telekinetically blasting someone into next week could be 50-100 calories or more.<br><br>Magic also has a few restrictions. Magic cannot effect non organic material like steel or plastic, although it could be used to levitate it, and magic cannot levitate living objects. For instance, you could turn a man's shirt blue, but you cannot levitate a man himself.<br><br>People with magic develop diseases that are highly lethal to non magic users. These diseases are referred to as "The Curses". The Curses come in many forms- boils, rotting flesh, falling Hair, sickness, itching rashes, coughing, etc. People without magic who contract a Curse almost always die, although there are exceptions. On the other hand, people with magic are largely immune to the curses. At most they will contract a minor Curse, although a small minority will develop severe Curses instead.<br><br>The final important aspect of magic is something referred to as a "Taint". People with magic give off an aura that non magic users cannot see, but they can feel. People with magic feel repulsed by this aura, while people without magic are drawn to it. People with magic are drawn to other people with magic because of the Taint.<br><br>Now, let's pretend we are talking about a medieval society with magic like this. How would magic change the economics of this place if 40% of all people had magic?