Flea is the common name for any of small wingless insects of the order Siphonaptera. Fleas are external parasites, living by hematophagy off the blood of mammals.
Cat Fleas (Ctenocephalides felis) and Dog Fleas (Ctenocephalides canis) are usually found together and are very similar in appearance. They are small, wingless insects about 1/8-inch long. They are dark-colored and have very narrow bodies with well-developed legs which allow them to be great jumpers. Their bodies are covered with backward-projecting spines that help them move between the hairs on the host animal. Adult Flea emerges from cocoon full-sized and ready to go. Cat and dog Fleas prefer these two animals, but will readily feed on man. The adult Fleas feed on blood with their pierce-sucking mouthparts.
Fleas can be a very difficult pest to get rid of as they can be brought in to your property from outside sources, even though you may not have a pet. Fleas can enter buildings that do not have pets as they can jump up about 6 in (15 cm) and enter on peoples’ shoes and clothes.
In most cases, Fleas are just a nuisance to their hosts, but some people and some animals suffer allergic reactions to flea saliva resulting in rashes. Fleas can also lead to hair loss as a result of frequent scratching and biting by the animal, and can cause anemia in extreme cases. Fleas can also act as a vector for disease. One possible example of this was the bubonic plague. Murine typhus (endemic typhus) fever, and in some cases tapeworms, Hymenolepis, can also be transmitted by Fleas