The cat flea is a small, sucking, insect of the order Siphonoptera. Adults range from 1–2 mm long and are usually a reddish-brown colour, although this can vary. The cat flea, and all other fleas, are compressed laterally, resulting in an extremely thin insect that can be quite hard to find in an animal's coat. The cat flea's primary host is the domestic cat, but the cat flea is also the primary flea infesting dogs in most of the world. The cat flea can also maintain its life cycle on other carnivores and on omnivores. Humans can be bitten, though a long-term population of cat fleas cannot be sustained and infest people. However, if the female flea is allowed to feed for twelve consecutive hours on a human, it can lay viable eggs.
Life cycle 
The female cat flea lays her eggs on the host, but the eggs, once dry, have evolved to filter out of the haircoat of the host into the resting and sheltering area of the host.
The eggs hatch into larvae, which are negatively phototaxic, meaning that they hide from light in the substrate. Flea larvae feed on a variety of organic substances, but most importantly subsist on dried blood that is filtered out of the haircoat of the host after it is deposited there as adult flea fecal material. Thus the adult population on the host feeds the larval population in the host's environment.
Flea larvae metamorphose through 4 stages before spinning a cocoon and entering the pupal stage. The pupal stage varies greatly in length; the pre-emergent flea does not normally emerge as a young adult flea until the presence of a potential host is perceived by warmth or vibration. Newly emerged fleas are stimulated to jump to a new host within seconds of emerging from the cocoon. The new flea begins feeding on host blood within minutes.
Effects on the hosts 
A few fleas on adult dogs or cats cause little harm unless the host becomes allergic to substances in saliva. The disease that results is called flea allergy dermatitis. Small animals with large infestations can lose enough bodily fluid to fleas feeding that dehydration may result. Cat fleas also may be responsible for disease transmission through humans, and have been suspected as transmission agents of plague.
Disease transmission 
Cat fleas can transmit other parasites and infections to dogs and cats and also to humans. The most prominent of these are Bartonella, murine typhus, and apedermatitis. The tapeworm Dipylidium caninum can be transmitted when an immature flea is swallowed by pets or humans. In addition, cat fleas have been found to carry Borrelia burgdorferi, the etiologic agent of Lyme disease, but their ability to transmit the disease is unclear.
See also 
- Pulicosis (Flea bites)
- European wildcat species account IUCN Species Survival Commission. Cat Specialist Group
- "Cat flea". Connecticut Agricultural Experiment Station. Retrieved 2008-10-17.
- "Fleas". University of Florida. Retrieved 2009-03-13.
- "Insects and Ticks: Fleas". Entomology Department at Purdue University. Retrieved 2008-09-08.
- "The Biology, Ecology and Management of the Cat Flea". University of California, Riverside. Retrieved 2008-09-08.
- Am J Trop Med Hyg. 1991 May;44(5):469-74
- Integrated Flea Control from University of Nebraska-Lincoln Extension in Lancaster County
- cat flea on the UF / IFAS Featured Creatures Web site
- About Ctenocephalides felis (cat flea): taxonomy, life cycle, transmitted diseases, eradication at MetaPathogen
Flea treatment 
- Dog flea treatments
- How to Rid Your Pet of Fleas from Wikihow
- Finding and Eliminating Fleas on Your Cat from the BBC
- Safe Use of Flea and Tick Products in Pets