The most realistic descriptions I have seen of live parasite-aware, say that de-workming is a yearly thing, a cycle, sometimes every 6 months if symptoms are bad. The reoccurance might be related to diet and what you're exposed to though? Much raw food is grown on soil with manure sprayed on for fertalizer.

I think this may also be the reason for the adamancy of folk who use Iodine heavily, and ionic therapies. Iodine is the most potent parasite killer in nature, and may act at a most basic level, like a daily herbal dewormer to a family dog.

What sort of cleanses have you been doing over these 18 months? I can't help feeling the biggest reason why they are coming back is that you never got rid of all of them to begin with. You need to do a sustained treatment that gets rid of them all and then continues for a while longer to catch any of the stragglers left behind that were in other parts of the body for a time. Their lifecycles often involve them only being in the intestines for part of the time. Ascaris spends a significant amount of time in the lungs for instance where it is very difficult to treat. You have to wait until you cough it up and swallow it and then you can get it in the intestines.

After you’ve got rid of them all then you should stay on a maintenance program as well using the Hulda Clark herbs perhaps.

Edit: forgot to mention importance of hygiene as well. Make sure you’re not reinfecting yourself