[Alneyan]

The Priestesses should be able to heal diseases, though it may take a little while as Diseased units can get all sorts of additional afflictions. On the other hand, I think Heal happens before further afflictions are created, so it should work all right.

Heal can remove all afflictions besides starvation and the ones created by wielded items, although some afflictions may be harder to cure than others (the Never Healing Wound for example).