A guy I work with took his girlfriend down to Costa Rica. They had a great time, but she came back with some kind of parasite. She had worms between her skull and scalp.
After several doctors, they figured out how to get them out. Shave her head. Lay raw bacon over the entrance wounds (yes, the worms would stick their little heads out when it was dark in her hospital room) and when they bit onto the bacon, the docs pulled them out. I don't know how many, but there were several. I will never go to Costa Rica.