Fleas

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Fleas

Adult fleas are wingless, reddish-brown, tiny insects (1/8"), which are flattened from side to side. They have well-developed hind legs that help them to jump from host to host. Adults have piercing-sucking mouthparts through which they feed on the blood of their vertebrate hosts. The cat flea, Ctenocephalides felis (Bouche) is most common in the USA and occurs on both cats and dogs. The dog flea, C. canis (Curtis), the human flea, Pulex irritans (L), and the Oriental rat flea Xenopsylla cheopis (Rothschild) are other common fleas in North America. There are a few other species that can be encountered by hikers or campers, but are uncommon inside homes.

Where do you find fleas?

Unlike many ectoparsites (parasites that are found on the skin of mammals), fleas do not spend all their time on hosts. While the adults do spend the majority of their time on hosts they can also be found away from the host in carpets on furniture, etc. or in areas where pets frequent. All immature stages including eggs, larvae, and pupae are found in pet bedding, in crevices on the floor, and in the nests of their hosts.

What do fleas feed on?

Adult fleas feed on the blood of their host animals (cat, dog, human, rat, mouse, squirrel, etc.). Larvae feed on the dried blood that is expelled in the feces of adult fleas and occasionally on molts from other larvae.

Do fleas transmit disease?

Some fleas such as the northern rat flea, the ground squirrel flea, and fleas found on prairie dogs are vectors of sylvatic plague, bubonic plague, murine typhus and tularemia. Most infections occur in hikers, or people frequenting the habitats where hosts of these fleas occur. House cats that hunt outdoors sometimes bring the host animals (rat, chipmunk, or ground squirrel) inside. Fleas from the host animal can sometimes transmit diseases to healthy people. In plague transmission, cats become infected and then they transmit the pneumonic (air-borne) form of the plague by sneezing on or around their owners.

Pets that are heavily infested with fleas may experience secondary bacterial infection of the bite sites due to intense scratching. People and pets that are allergic to flea bites can develop dermatitis or hair loss and intense itching may result. Cat fleas may also serve as intermediate hosts for the development of dog tapeworms. Adult fleas contain cysts with the tapeworms inside of them. Ingesting adult fleas during grooming can infest healthy cats and dogs.

What is a flea's life cycle?

The life cycle of all fleas consists of the following: egg, three stages of larvae, pupae, and adult. The only variation between life cycles is the time spent in development of each stage by various species. First, females take a blood meal and egg development begins. The duration of egg development is dependent on environmental factors, such as temperature. There is also variation in the number of eggs laid by different species. Cat fleas lay about 25 eggs after each blood meal and may lay more than 1000 eggs during their lifetime. Eggs are white, oval in shape and 1/32" in length. Although the eggs are laid in the fur of the host, they can drop into nesting material, crevices on the floor and/or into host bedding.

Eggs hatch within 2-21 days of deposition. The newly hatched young, or larvae, are white and worm-like, with a well-developed head but no eyes. The larvae molt three times, increasing in size each time. The development takes from one week to several months. After the final molt, pupae or cocoons are formed. Pupae are covered with silk secreted by the larvae. An adult flea develops inside the pupal skin where it will remain dormant in the absence of a host. Adult fleas jump out of the pupal skin as soon as they detect vibration in the environment, which indicates the arrival of
a host.

Adults can survive for several years and can withstand long periods of starvation. Fleas can breed from two weeks to three years depending on availability of hosts and environmental factors.

What can I do in my home to control fleas?

To reduce the overall number of fleas, regularly bathe your pet and comb its hair to remove fleas. Thoroughly wash and vacuum all pet bedding regularly. Vacuum all upholstered furniture and carpets. One treatment option is to treat furniture or carpets with insecticide containing an insect growth regulator. Pet collars containing flea deterrents and many insecticides are also available. Always consult a veterinarian before using any insecticide, shampoo, and/or growth regulator on
your pet.

Please visit the web sites below for further information about fleas and their control in and around your homes.

More Resources

University of Florida Cooperative Extension Services

The Ohio State University Extension