Fleas are small insects that survive by feeding on animal or human blood. Their bites can cause discomfort, itchiness, and irritation. Sometimes, fleas can infect people or pets with the germs that cause flea-borne typhus, plague, or cat scratch disease.
Transmission
Fleas transmit germs that cause disease primarily through the processes of feeding on hosts or through fecal contamination, when infected flea feces (poop; also called “flea dirt") are scratched into an open wound.
Fleas prefer animal hosts but will resort to biting people when animals are unavailable. Adult fleas find hosts by detecting body heat, movement, the vibrations caused by movement, and breathing.
Preventing Flea Bites
The best way to prevent fleas on people is to keep pets free of fleas. Most fleas in the United States prefer to feed on animals, however, people are sometimes bitten out of convenience when they share space or come into contact with a flea-infested animal.
To protect yourself from flea bites:
- Use an EPA approved insect repellent that has DEET, picaridin, or oil of lemon eucalyptus.
- Wear long sleeve shirts and pants
- Treat clothing and gear with products containing 0.5% permethrin.
- Do not feed or pet stray or wild animals.
- Always wear gloves if you are handling sick or dead animals
Fleaborne Diseases of the United States
In the United States, some fleas carry pathogens that can cause human disease, including:
- Plague — most commonly transmitted to humans in the United States by infected ground squirrel fleas, Oropsylla montana, and globally by infected Oriental rat fleas, Xenopsylla cheopis. Also, may be transmitted by improperly handling an animal infected with plague bacteria. Most U.S. cases occur in rural areas of the western United States.
- Flea-borne (murine) typhus — transmitted to people by infected cat fleas, Ctenocephalides felis, infected Oriental rat fleas, Xenospylla cheopis, or their feces (poop; also called “flea dirt"). Most cases in the United States are reported from California, Texas, and Hawaii.
- Cat scratch disease (CSD) — transmitted to humans most often after a scratch from a domestic or feral cat that has been infected by a Ctenocephalides felis flea, or through flea feces (poop; also called “flea dirt") being inoculated through a cat scratch. CSD occurs wherever cats and fleas are found.
- Fleaborne parasites, such as tapeworms can spread to people and animals if they accidentally swallow an infected flea. Small children are at a higher risk than adults, as they may spend more time close to the floor and carpeted areas where fleas are found. Most infected people will not show symptoms and will not know they are carrying tapeworms.