I experienced also this fleas problem with my dog and my friend advice me to do a natural remedy. I always give my dog a bath and I use a gentle shampoo, I was first the part where fleas can find. After that, I make my own herbal flea dip and then when my dog is dry I use a flea comb. For the last, before I put the collar of my pet I put on drops of eucalyptus oil, tea tree oil, citronella, lavender, or geranium and do it weekly.