It shouldn't really. Your immune system evolved in an environment where it expected to be under constant barrage from foreign organisms, in the absence of those many modern people suffer from diseases of the immune system where it misbehaves because it doesn't have enough to do.
"Most infected cats will shed oocysts only once in their lifetimes, for a period of about one to two weeks."
Your question is best addressed to your physician. If you spend too much time reading about diseases, you'll spend all of your time needlessly worrying about them.
Yeah, I look forward to perfect medical-introspection technology, but I don't think we're ready for what we'll find. I suspect we'll find that we're positively riddled with parasites, subclinical tumours, and all kinds of squick.
That's almost inconceivable. The other studies around this bounce from 10-25% too. I assumed toxoplasmosis was rare - but that kinda scares me.
How do I get a test for me and the family?