Someone please correct me if I'm wrong b/c this is just from what I've read...but I've read that Ivermectin can work well for worms that have scattered. I've also read good things about Albendazole too. Consistency seems to be the key. Hit them hard so they have no chance to build up a resistance to it. If you can't find the meds in the U.S. you can order from mymexicandrugs or farmaciadelnino online. They carry most medicines at low cost.