Yeah but the biggest thing it affects is birds, and even then it only gives them stomach ache. If you want neat parasites, look out for Tapeworm. It's usually harmless to humans because the dangerous part of its life cycle occurs in pigs, but if you eat the half-egg...
So basically, when you eat a tapeworm egg, it latches onto your intestine and begins to grow like a weird tube - it grows sections or segments. When it's mature, the end segment breaks off and is excreted. This excrement is usually ingested by pigs. If it is, the segment burrows out of the digestive tract and into the bloodstream, where it makes its way to the muscles of the pig and grows into a cyst filled with eggs ready to be eaten by a human (always check your pork for lumps). If a human eats a segment, the same thing happens but instead of happening in the human's muscle, it happens in the human's brain... where we have no immune system and it just keeps on growing and gives you a bunch of mental issues and then you die.