After Buddha died, his shadow was still shown for centuries in a cave—a tremendous, gruesome shadow. God is dead; but given the way of man, there may still be caves for thousands of years in which his shadow will be shown. And we—we still have to vanquish his shadow, too.
Pick up a pathology/microbiology book, and add the diseases/syndroms to your game. Your players will freak out.
Coughed at? Diphteria. or tuberculosis?
Drunk from a muddy stream? Or just walked through? Well, let us introduce you to schistosomiasis...
Hit by a stream of energy? Too moch mana is ust like too much radioactivity - perhaps all mages could develop cancer early if too powerful...