My fiancé has a parasite

We just found out my fiancé apparently has "rare blastocystis hominis" which apparently is a parasite. I'm freaking out. This is my worst fear come true. Some people have extreme fears of spiders or snakes and mine are parasites (fleas, ticks, bed bugs, worms, lice) idk what to do. His doctor was not helpful in explaining anything AT ALL. I'm so frustrated with them both. I've tried googling information about this stuff and everything I read says something different. Is there any off chance that anyone on this app at all actually knows ANYTHING about "rare  blastocystis hominis" such as, how contagious it is, what kind of problems if can lead to, how he could have gotten it, if I could have it, if our dogs could have it (they've been dewormed recently and nothing was found), if this means he actually has worms..? I just don't get it. They prescribed him an antibiotic and then I read some stuff that said they don't even work. Any factual information anyone may know from working in the medical field or actually from experience would be greatly appreciated. 😩😩😩😩😩