The problem in treating fleas is that fleas live only part of their life cycle on the host, the rest is usually oon the floor, in the carpet. Adult fleas stay on the cat, get their blood meals there, and lay their eggs there. The eggs fall off onto the floor, hatch into flea larva which live on dander and flea droppings, develop into pupa, and when ready, come out of the cocoons as adults looking for a new host, which is likely your cat. You are removing some of the adults, but missing the eggs, larvae and pupa. There are several approaches you can take; use Frontline on the cats, or wash and comb the cats daily and treat the house for larvae. Frontline will kill the adult fleas, and if you use Frontline plus, it will keep the eggs from hatching. You probably only need to use it one time, as it remains effective against fleas for up to 3 months, which is many flea life cycles. If you would prefer not to use Frontline on the cats, you could bathe the cats, comb them daily to remove the adult fleas, and treat the flea larvae by either bombing the house, or by vacuuming the floors and furniture and then sprinkling borax on all horizontal surfaces, working it in well. and repeating each time you vacuum. I prefer the Frontline as it is much less laborious, but either will work. I do not use Frontline as a flea preventative, rather as a flea treatment.
