Worldwide, there are over 2,000 species of fleas. They prefer to live separately and do not interbreed. Fleas are important because of their direct effects on animals (and people) and because of the diseases they can transmit.

Some of the more important fleas include:

  • Pulex irritans is the human flea. This flea also infests swine, and occasionally dogs and cats.
  • Ctenocephalides felis is the domestic cat flea, but it actually prefers dogs. This is the most common flea that affects dogs and cats.
  • Ctenocephalides canis is the common dog flea. Despite its name, it also feeds on humans, cats, and other animals.

All of these fleas have their preferred hosts, but all will feed on dogs and cats. With such a huge range of fleas that can and do feed on dogs and cats, it is easy to understand why their numbers are so difficult to control.

Flea Anatomy

Fleas are insects, 2-8 mm long, and th