The most common flea species that humans come into contact with is the cat flea, which despite its name is commonly found on dogs. Even if you no longer have a cat or dog in your house fleas can remain dormant for up to 18 months.
The adult fleas live exclusively as parasites of warm-blooded animals, with wall to wall carpeting and soft furnishings providing a relatively undisturbed environment for them to develop. They can also live in cracks and crevices in bare floors.
Fleas are not thought to transmit any serious illnesses to humans though the bites produce inflamed dark red spots and can cause severe irritation in some people.
Dealing with the problem yourself
We would always advise that you seek professional help when dealing with fleas as they are difficult to eradicate.