Probably roundworm or toxocara. I would probably treat with additional protocols and if I didn't get help I would test thru Metametrix (GI Effects - use panel #2105).
There are multiple products that can work to get these out, Black-Walnut products are just one. I got roundworm using boswellia, myrrh, neem and enteric coated oil of oregano from NOW. I would add a product called VER from Deseret Biologicals. Another option is a product from Banyan Botanicals called ParaCleanse. If these do not work then test, you may have to look at pharma products such as Vermox or Albendazole.