Squirrels, like most wild mammals, host a variety of external parasites, including fleas. These small, blood-feeding insects live primarily within the squirrel’s dense fur. While squirrels are not a primary source of household flea infestations, their presence near homes can increase the risk of exposure to flea-borne diseases. Understanding the specific species of fleas involved is key to minimizing potential transmission risks on your property.
Identifying Squirrel Parasites
The most common flea found specifically on tree squirrels across North America is Orchopeas howardi. This species is host-specific, preferring to live and reproduce only on squirrels. However, squirrels can also host generalist fleas, such as the common cat flea (Ctenocephalides felis), which infests a broad range of animals including raccoons and opossums.
Fleas and their eggs accumulate not only on the squirrel’s body but also in its nest or drey. This distinction between host-specific and generalist fleas is important because generalist species are more likely to successfully infest a dog or cat if they jump from the squirrel host.
Transmission Risk to Pets and Humans
The risk of flea transfer is generally low when squirrels are alive, as fleas prefer to remain on their host. Fleas typically seek a new host only when the squirrel dies, abandons its nest, or when the nest area is disturbed. If a squirrel dies in an attic or wall void, its fleas will quickly leave to find a new source of blood, potentially a nearby pet or human.
Pets that spend time outdoors, especially near squirrel nests or frequent areas like under decks, face the highest risk of picking up these parasites. Humans are typically bitten opportunistically when walking through heavily infested areas or handling dead wildlife. While a squirrel flea may take a blood meal from a pet or human, it usually cannot establish a sustained population away from its natural host.
Zoonotic Disease Potential
Squirrel fleas can act as vectors for infectious diseases transferable to humans. The most serious concern is the transmission of plague, caused by the bacterium Yersinia pestis. Although this disease is maintained in wild rodent populations, most human cases in the United States are linked to ground squirrel fleas and occur in rural areas of the Western U.S.
Another potential flea-borne illness is typhus fever, sometimes associated with flying squirrel fleas. Murine typhus, caused by Rickettsia typhi, is primarily linked to rat and cat fleas. The disease-causing bacteria are often transmitted when infected flea feces are scratched into the bite wound, rather than through the bite itself. While the potential for transmission exists, these diseases are uncommon.
Homeowner Prevention Strategies
Homeowners can reduce the risk of flea exposure stemming from local squirrel populations by discouraging them from nesting near the house. The most effective strategy involves removing accessible food sources. Secure all garbage cans with tight-fitting lids and avoid leaving pet food bowls outside, as these attract squirrels and other flea-carrying wildlife. Trimming tree branches that overhang the roof can also prevent squirrels from gaining easy access to attics or eaves, which are common nesting sites.
Preventative flea treatment for domestic pets is highly recommended, especially for animals that spend time outdoors. Year-round use of veterinary-approved flea and tick products creates a barrier, ensuring that any squirrel flea that jumps onto a pet is quickly eliminated. For the yard, keeping grass short and reducing moisture helps limit the overall flea population.
If a dead squirrel is found, handle it with caution to prevent contact with abandoning fleas. Use gloves and avoid direct skin contact when removing the animal, or hire a professional wildlife control service for safe disposal.