It seems to me that you can't isolate yourself from everyone. Just be careful what you put in your mouth - wash your hands and don't eat foods that are suspect. We're around parasites ALL THE TIME - in my opinion the best you can do is get your body healthy and fight off what you can. There isn't an office on the planet that doesn't have a ton of people with parasites in it, and just about everyone has pets.
I think I got parasites bad because my body was already very depleted, and I wasn't careful. I think many others in my same physical circumstances would have been just fine.