It is amazing how many people worm their dogs and cats, but they don't worm themselves. They say " parasites are normal, everybody has them. And besides, we need them because they are beneficial."
Horse manure!
If a microbe is beneficial the relationship is symbiotic, not parasitical. It is the entities that are living in the body and feeding off the body to the detriment of the body that are parasites.
It is disheartening how many of my friends and relatives think I am nuts for wanting to live parasite free. I just tell them it's a phase I'm going through. Acquaintances tend to distance themselves at the mention of parasites, but I don't really care. As hard as I've worked to get rid of these things, I don't want to rub up against anybody who isn't deworming regularly.