Walking through their new home should have been an exciting experience for my parents. However, they unknowingly bought a house with a flea infestation, even though it had been vacant for quite a while. Apparently, fleas can live in a home, even without pets.

We spoke with pest control experts to learn how an infestation can happen in a pet-free home, and how long these parasites can live there.

How Do Fleas Get Into Homes Without Pets?

Fleas can infest your house in several ways. Here are the most common scenarios:

• Carried in by other animals: Frank Meek, a board-certified entomologist and technical services manager for Orkin, says a mouse, rat or squirrel can bring them in. Even if the animal is trapped and removed, the fleas can stay behind. “The fleas that previously fed on it are forced to focus their feeding activity on other hosts that reside in the home,” he says.

• Attaching themselves to various materials: “[Fleas] have the ability to jump as high as six inches,” Meek says. “They can easily hitch a ride from place to place, and they’re able to attach themselves to clothing, bedding or furniture.”

• Dormant flea larvae: “Developing fleas in the larval stage can stay dormant for months, emerging when they detect a food source,” says Nancy Troyano, Ph.D., director of operations, education and training and a board certified entomologist with Rentokil. “Therefore, if a rental unit has an untreated flea infestation but is then emptied of people and pets, the flea larvae in cocoons can remain dormant for six to 12 months, waiting until they detect a host.”

How Can You Tell if Fleas Are in Your Home?

Here are the most common signs Meek says to watch for:

• Bug bites on your body: Bites on the legs and ankles of human victims are usually a common indicator. Flea bites result in red spots surrounded by reddened halos. They’re extremely itchy and cause great discomfort.

• Adult flea feces: Sometimes called flea dirt, you’ll find it on carpets and rugs. It looks like course ground black pepper.

• You’ll actually see them: Adult fleas are relatively easy to see. In more extreme cases, when occupants of the home return after a long vacation or other absence, they’re often greeted by fleas jumping around and trying to land on them.

• You find eggs: Larvae and pupae may appear in out-of-the-way places, like under baseboards, inside cracks and grooves in the floors, or around the edge of the carpet.

How Long Will Fleas Live in a Home Without Pets?

Meek told us adult fleas could live for up to 12 months in the right conditions.

“As long as there is a host to feed on, untreated flea infestations will continue to thrive,” Troyano says. “The most common flea that we see infesting homes in the U.S. is the cat flea, Ctenocephalides felis, with cats, dogs and other mammals such as raccoons as their preferred host. These fleas will readily bite humans to feed but cannot proliferate on humans alone.”

Besides bites and allergic reactions, fleas pose other risks. “Fleas are also an intermediate host for tapeworms and are commonly associated with tapeworm infections in pets and, occasionally, people,” Trovano says. “Fleas can also transmit diseases such as plague in places where these diseases are endemic.”

How To Get Rid of Fleas

Meek says getting rid of fleas means targeting the root of the problem.

“Upon identifying an infestation, it’s important to clean your home thoroughly,” he says. “Linens, floors and carpets should all be cleaned and vacuumed.

“Flea management may require the use of both conventional insecticide products as well as flea repellents. It’s important to contact your local pest control expert to discuss customized solutions for your home and extermination options.”

Troyano also warns eliminating flea infestations is a complex process.

“There are over-the-counter products that can potentially be effective in lighter infestations,” she says. “However, products such as `flea bombs’ may wind up dispersing fleas to a wider area rather than killing them. Insecticides used to treat fleas should include ones that are effective at killing adults as well as larvae.”

Trovano recommends hiring a pro for treatment. “Pest control professionals are trained to apply the right combination of insecticides to the right places,” she says. “However, they do need the help of the homeowner to vacuum several times a day after treatment in order to stimulate the fleas to emerge from their cocoons to contact the insecticide.”

Also, Trovano says, seal up any foundation-level cracks or access points, whether you have a crawl space or a full basement. Check under decks as well. Simple exclusion techniques like screening can go a long way.