Many medics go into the profession of
worm parasitologist voluntarily. They have to face such foes as the Ascaris lumbricoides whose
eggs hatch in the small intestine. The worms travel to the lungs, are coughed up, and then swallowed into the gut where they will each grow to a length of sixteen inches, and where the females will lay billions of eggs. Another such enemy is Wuchereria bancrofti, a worm that settles in the scrotum and blocks the flow of lymph. This blockage can result in emmensely swollen testicles combined with the smell of death. There are many other parasites, and most people don't know about them. The world is just not ready for some of the disgusting stuff that exists out there.
More abstracts about the Worst Science Jobs: Worm Parasitologist