There are many types of fleas, most of which are brought indoors by cats and dogs or humans, but can be found in gardens, outbuildings and roof spaces.
All fleas feed on blood, be it animal or human, and they can carry numerous diseases although this is rare in the UK.
Usually of most concern is the distress flea bites cause to humans and animals.
Adults fleas can be 1-8 mm long with a very compressed body, muscular legs with the hind legs adapted for jumping.
Flea eggs can remain dormant for two years or more, but are stimulated by the vibration of footsteps.
Signs of a flea problem:
Bites (tiny, dark red spots surrounded by a reddened area), which are normally below the knee and above the ankle and are intensely irritating.