You mention the immune system a lot . Just my 2 cents worth and my millions of dead worm thoughts . As the worms thrive on bacteria farmed from boring tunnels in your intestines bringing bacteria in places it shouldn't be also drains your immune system . When battling a nematode infection , you are also battling bacterial and fungal infections . When worm load suddenly drops from meds fungal infections and kidney and bladder infections (bacteria) were common in my recovery . Fenben kept my fungal infections under control along with worms and the doxy always eliminated my bacterial infections (back pain ) . Bacterial infections are usually the cause of death in strongyloides disseminated hyperinfection so taking tetracycline(doxy ) in my case was wise .