Are the worms like a fine silk thread of white , or sometimes red in color . It sounds like they responded to the ivermectin but I need to hear a detailed description of symptoms . Where do you live in general ? I will help if I can, if not I can forward your symptoms to my mom who is a retired farm vet and is quite knowledgeable , and was the one who diagnosed me when specialists failed. She taught me the black rag trick to find threadworms in her field of work. Let me know.