Parasites in all sizes are the Cause of leaky gut and such chronic conditions at FM/CFS, Crohns, IBS, etc...
Probiotics help, but you have to kill the dragons first. We have spent years taking expensive supplements and probiotics only to discover that we had illegal aliens taking everything from us, leaving only leftovers. Helminths love multi-B vitamins, especially B-12.
Go to www.humaworm.com and read the testimonials there with regard to FM/CFS.
We worm our dogs, cats, horses, goats....but do we ever stop to consider that we, who are at the top fo the food chain, never consider that periodic parasite maintenance might be in order?
Extensive research has yet to confirm any parasites as the cause of ME/CFS as far as I have seen. If you have any links to the contrary, please provide.