Fleas thrive in damp, grassy areas, including the areas underneath porch steps, along nearby ponds or even in the shade of bushes or trees; raccoons, squirrels, rodents and feral cats carry fleas into the yard. Once fleas are inside, they can live virtually anywhere, including on pets, in carpet and on furniture.
According to PetMD, it only takes a few fleas to cause a massive infestation of the yard, pet and home. Even human visitors can bring fleas into a home, including people who live in the home who may have been exposed to fleas that cling to shoes, socks or the legs of pants.
When a pet is taken outside for a short walk or play date at the dog park, the pet can be exposed to fleas. Visits to the vet, staying in a boarding kennel, riding in a car and even trips to the groomer can expose a pet to fleas. For this reason, checking for fleas after a trip to the lake, a hike in the woods or other excursions is a first line of defense against fleas. Treating any infestation of fleas immediately and being diligent in watching for fleas to hatch after treating an initial infestation is important to controlling fleas.