I think some parasites can hide, and would take hunting to find. I guess TBP had plenty, so easier to find. :)Oh, here's an indelicate question. You didn't have to dig around in the toilet looking for those things did you? I mean, could you just see them without stirring the pot, so to speak? Seems like another poster said they had to dig to find them, couldn't find them by just looking...
I couldn't be bothered when I did my anti-parasite treatment, so I don't know if I got anything.
I found worms in my kids when we were out in a forest - that i did not spot in normal toileting. Potty might be easier. I think some people sling a sieve under the dunny seat.