Common Fleas of the United States

There are more than 2,500 flea species worldwide, with more than 300 species occurring in the United States. However, of the many different fleas in the world, only a select few can affect people’s health.

Magnified photograph of an adult cat flea
  • Cat Flea (Ctenocephalides felis)
    • Transmits: Flea-borne (murine) typhus and cat scratch disease (CSD)
    • Comments: Despite the name “cat flea”, this flea is the most common flea found on pets (including dogs) and other domestic animals in the United States. It is capable of spreading plague bacteria, but does so inefficiently compared with ground squirrel or rat fleas.
Magnified photograph of 2 adult dog fleas.
  • Dog Flea (Ctenocephalides canis)
    • Transmits: Aids in spreading Dipylidium caninum, a tapeworm commonly found in dogs and cats, but occasionally found in humans.
    • Comments: Despite the name, the dog flea is not a common flea of the domestic dog in the United States.
  • Magnified photograph of an adult ground squirrel flea.

    Ground Squirrel Flea (Oropsylla montana)

    • Transmits: Plague
    • Comments: Frequently associated with ground squirrels, including California ground squirrels and rock squirrels, which are known to aid in the spread of plague bacteria to people in the United States.
  • Magnified photograph of an adult Oriental rat flea.

    Oriental Rat Flea (Xenopsylla cheopis)