When dealing with Fleas you have to understand that they have a life cycle. The fleas infesting your dog are small and don’t fly and the only source of nourishment is from the blood of your dog. They are small but not too small that you cannot find them by just looking for them, having said that if your dog had dark fur it is much harder to spot them. A flea goes through four distinct stages in its lifetime: egg, larvae, pupae and adult. Female fleas lay eggs in batches of 18 to 22 eggs per gestation. They will lay their eggs on your do however a majority of those eggs fall off your dog and go elsewhere in your home and this is by design. In comparison to the mature lea which is visible to the naked eye – the flea eggs are very small greyish white in color and an oval shape not unlike a chicken egg just much much smaller. Once the flea eggs hatch the larvae feed on feces or rotting vegetable matter. Following the larvae stage they will quickly spin cocoons and hang tight for about two weeks while they mature. When they leave the cocoon they must quickly find a host, usually your dog or you and then begin the cycle of feeding off of the blood of the host.
The best way to treat your dog when he/she is infested with them is to consult with your veterinarian and kill the adult fleas and stop the cycle. This does involve that all bedding material and surround area be disinfected and treated as well. Fleas on your dog is not something you can cure in a day or two it takes weeks to kill the life cycle of the flea. Best of luck!