Is the Cat Flea a Public Health Risk?

Bites of cat fleas can be very annoying to humans because chemicals in flea saliva stimulate an immune response that causes itching. The same immune response can be much more severe in dogs and cats, possibly producing a serious allergic response known as flea bite allergy in susceptible pets. You should take pets suffering from this condition to a veterinarian for treatment and consultation about approaches to flea control.

How Can I Recognize a Flea?

Adult fleas typically are about 1/8 inch long, oval, and reddish-brown. They are wingless, and their bodies are very thin, so thin that they can move freely through fur or feathers of their host. They possess very large hind legs that are used for jumping and a very slender proboscis (beak) that extends forward when the flea takes a blood meal. At rest, the proboscis projects downward and backwards between the legs, but it cannot be seen without the aid of a microscope. Similarly, recognition of flea larvae and pupae typically requires the use of a microscope. To the unaided eye, the legless larvae resemble tiny whitish “worms.” Flea pupae most likely would not be recognized at all because they are encased within a sticky cocoon covered by incorporated soil particles and small items of debris from the habitat in which the larvae develop.

Where Are Cat Flea Larvae and Pupae Found in Homes and Yards?

Cat flea larvae and pupae are found in and around areas where pets are active and where they sleep. Indoors, common sites include pet sleeping mats, among fibers of thick carpets, in upholstered furniture, and on bed covers, if pets are allowed to sleep there. Outdoors, under warm and humid conditions, cat flea larvae and pupae can develop in certain sites were pets frequently rest. One of the most common is in moist, shaded soil beneath shrubs. Another site is in the small amount of soil found in joints of concrete walks and porches.

How Do Pets Become Infested and Pet Owners Get Bitten

Adult cat fleas usually reside and feed on a single host dog or cat. Pet to pet transfer occurs when pets interact and when they sleep together, but transfer of cat fleas from infested pets to pet owners appears to be uncommon. The usual way in which a human gets bitten by a cat flea is when a “hungry” adult emerges from its pupal cocoon and jumps onto a person walking in their vicinity. The presence of flea bites on a person suggests that the home (or a barn) is supporting the development of flea larvae, which can be a continuous source of adult fleas that then infest your pets. The cat flea also is capable of infesting and feeding on a range of domesticated animals. Common hosts include chickens and livestock, especially calves and pigs. Certain livestock production methods can provide ideal conditions for the development of very large numbers of flea larvae, including those associated with the use of straw that becomes contaminated with livestock urine and feces. Infested barns can be a continual source of adult cat fleas that can infest cats and dogs that sleep in them, and a source of flea bites to people who enter them.

How Do Cat Fleas Survive Winter?

Only adult cat fleas appear to be capable of surviving winter in Indiana. Some adults may continue to infest pets during winter, but the most common hosts appear to be wild mammals such as coyotes, raccoons, and opossums. Cat flea eggs, larvae, and pupae are not known to survive winter outdoors and typically are not found indoors during winter.

How Do Humans Influence Cat Fleas?

Pet owners contribute to the success of cat fleas by failing to monitor their pets for the presence of adult fleas and by failing to practice sanitation methods that reduce the development of flea larvae. Again, cat flea larvae and pupae are found in and around areas where pets are active and where they sleep. Owners should keep these areas clean (see below), and periodically launder pet sleeping mats and bed spreads, if pets sleep on them.