myrkul, you have a horribly infectious disease that will kill all the people around you.
Now I'm guessing that since you've been told, you will not take any action on this. This is because you don't believe me. So now do we need to create a standard for belief? This is what the statist system does: it creates the AMA and the people within it have authority to decide if someone has a serious enough disease that force can be used against them.
However, in a voluntary society, each individual sets the standard by which they go. So when the employer interviews her, they say "Has an insured doctor ever examined you for disease? Did they conclude you were disease free? What is that doctor's name?" There's even more complex things like there could be cooks' insurance companies that will bond a cook for not having infectious disease, and the employer could just ask if they are bonded for it. And then when she is not bonded, they don't hire her. This put it on the employer, not on Mary.
And if an employer wants to take a chance and use her anyway, then they should be allowed, even if it would probably result in their certain death. This is the point of voluntaryism.
But I agree that the end result for her will be that she would be ostracized at some level and she would then only have the option to self sustain as a hermit or voluntarily check herself into a charitable quarantine.