Hmm... The wiki page says that about the antibodies, i.e., that many people have at some point been infected... but my understanding may be off

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.