What causes parasites to damage the health of people?

Anecdotal personal experience: About four years ago, I started to experience sarcopenia (muscle weakness in legs). I forced myself to be more active - thinking my aging muscles were getting flacid and weak. Last June 2022, I read here on AU that all diseases are caused by parasites. My intuition told me that was true and I ordered ivermectin-12mg. I took one pill a day for 100 days and my legs are as strong as they were in my 30s. No hint of sarcopenia. Looking back on what happened - I think I had an infection of parasites throughout my leg muscle tissue. I think the "home base" for the parasites was in my right calf in a benign cyst that I had had since a teenager. After the IVM treatment, the cyst was gone and my calf muscle was flat again. I have also read that parasites are very hard to remove completely from your body - so right now I am in the middle of a fenbendazole (222mg) treatment plan - focusing on my abdomen and intestines. I am very pleased with fenben.... 💞