Fleas are parasites, feeding directly on humans or other warm blooded animals. Usually you or your pet serve as these hosts.
A flea can jump 7 to 8 inches vertically and 14 to 16 inches horizontally.
A skin reaction to a flea bite appears as a slightly raised and red itchy spot.
Sometimes these sores bleed. Fleas usually require warm and humid conditions to develop.
Due to the flea cycle and weather conditions, many people don't realize they have
a flea problem until they return home from vacation or after a move to new premises
and are confronted by hungry fleas. There are several types of fleas,
but the most common is the cat flea, even on dogs.
Fleas are attracted to body heat, movement, and exhaled carbon dioxide.

The average flea ranges in size from 1/12 to 1/6 inch long.
Fleas are very small and have no wings.
Their bodies are narrow if viewed from the sides.
Slender fleas can get into and move around in narrow areas.
Because their bodies are covered with spines projecting backward, they are difficult to remove
by shaking or scratching.

Adult fleas feed on blood; the larvae eat "flea diet" consisting of dried blood.

Fleas go through a complete metamorphosis. There are four distinct stages:
eggs, larvae, pupae, and adult.
Flea eggs are laid on the host or are deposited on the floor or ground.
They also are often found in upholstery or pet's bedding.
A female flea will continue to lay a few eggs every day until she has yielded up to 200 to 400 eggs.
These eggs will develop into flea larvae within 2 days to several weeks, depending on the temperature and humidity.
Flea larvae are active and look like maggots.
The larvae will feed on organic debris, but particularly like to feed on feces of the adult fleas.
This "flea diet" contains undigested blood.
The flea larvae are hard to spot and are found deep in the carpets or the cracks and crevices of floors and upholstery.
They are very difficult to vacuum, because the get entwined in the carpet fibers.
The next stage, called the pupae look like a cocoon, also hard to spot.
Under warm conditions many adult fleas will emerge
from this protective cocoon within 7 to 14 days, longer under less favorable conditions.

Whenever you see adult fleas crawling on your pet,
it is only a symptom of a much larger problem.
Current studies indicate that adult fleas account for only 5%
of the total flea population in any given situation.
Eggs account for 50%, larvae account for about 35%,
and the remaining 10% are the pupa cocoons. That means that for every single adult flea
living on your dog or cat, there are 10 eggs, 7 larvae, and 2 cocoons

These various life cycle stages will be found anywhere in the pet's environment,
but will be most concentrated in the areas that the pet spends most of its
time, like the pet's bed area. Remember, when the adult flea lays an egg on the pet,
it will fall off the hairs in just a few minutes, similar to sowing seeds.
If the pet usually walks through certain paths (either indoors or outdoors),
there will also be a substantial amount of eggs scattered in those areas.

What this means is that environmental flea control must be spread over the pet's entire environment,
focusing on the areas the pet spends the majority of his or her
time: the sleeping areas and the walking paths.

The best time to start a flea control program is in the late spring,
prior to an infestation,
since adult fleas comprise only 5% of the total flea population.
To contain an infestation, fleas must be controlled in every way:

Frequently dust, sweep, vacuum, and mop all surfaces where pets or you
have been. Eggs are laid on the pet and drop off as it moves.
All affected pets should be treated at this time and removed from the premises for 4 to 6 hours.
Remove birds from the home if you are using liquid insecticides.
Cover or remove fish, and turn off the pump.
You should keep covered shoes on until all treated areas have dried (4-6 hours) if you are using liquid insecticides.