(its an all-female profession babey, I'll explain in depth the lore posts after fleshing out the designs of the different branches)
The plague doctors were founded during a war because of a lack of medical care on all home fronts. The women on all sides eventually teamed up to create a new branch of medicine to save themselves from all sorts of epidemics, magical or otherwise. Over time it has evolved into something more than a career, but you'll have to wait and see what kind of mutations theyre subject to ;)