I takes years for some parasites to get to a point where the infection is noticeable, so it would make sense that it would take awhile to get rid of them.
I'll be fighting my threadworms the rest of my life, because they are resistant to everything, even pharmaceutical drugs. As near as I can figure it, I've had them for over 20 years, from when I lived on a farm for 5 years. It took a long time to find out that was what it was. I have been diagnosed with everything from lupus to thyroid disease.
I'll be on my second dose soon, and saw real improvement from the first one. I'm hoping that with continued rounds of Humaworm, I can get them back down to a manageable level.