Side note: If you have an immune disorder of any kind than more precautions are wise, of course. But even so a couple days of antiparasitic meds will wipe that right out so I wouldn’t lose sleep over it.
And yeah, if people were getting parasites from their aquariums I’m pretty sure we’d have heard about it.
The one I have heard about is fish tb which can apparently cause some Issues in people, has been reported rarely. and if you work in the tank with an open wound there is risk of bacterial infection just like if you put an open wound in a pond. As I said, take some basic precautions like not sticking an open wound in your tank, but other than that if you have a normal immune system it’s really not something to worry too much about.
(I do have my PhD in biology, for what it’s worth, so if it makes you feel better a doctor said you’re gunna be fine :P)