Has anyone experienced dog lice before? My puppy came home with them in April and we have had an ongoing battle since. I thought I had killed them all but before long all the dogs were scratching. I did a weekly flea bath, as vet ordered for all dogs for 6 weeks. I normally bathe dogs once a month. Anyway, dogs are starting to scratch again and I wonder if it is the dog lice again. Should I break down and get frontline? I just don't know what more I can do. Dogs are inside dog and I can't throw out the carpet. How long does the eggs stay viable, because I know I am killing the adults with the flea bath?