Puppies are not born with fleas. If a puppy has fleas, it is because fleas are already present in the home, in the birthing area or on the mother herself. To prevent fleas on newborn pups, any flea infestation must be eliminated before the puppies arrive.
Fleas are widespread and common throughout the world. When dogs come into contact with other dogs or animals, fleas can transfer between them. Fleas often infest yards, and a few can turn into a full infestation in a short time. Dogs that play outside often bring fleas into the home unless prevention measures are taken.
A female flea can live for several weeks and lay 20 to 30 eggs a day.