Flea Infestation (Feline)

Flea infestation is a common condition of cats, especially those that live in multi-pet households with outdoor exposure or in households with dogs.

Serious health consequences may result from a flea infestation. Many safe and effective flea treatment and preventive products designed for cats with a flea infestation are available.

Common name: Flea infestation, Fleas. Scientific name: Flea infestation

Diagnosis

Signalment All cats are susceptible to flea infestation, but risk is directly associated with exposure. Therefore, cats with exposure to the outdoors or living in multi-pet households, pet stores, catteries, or shelters are at highest risk. Cats that visit boarding or grooming facilities may also be at increased risk for flea infestation.

Incidence/prevalence Ctenocephalides felis accounts for 97 percent of flea infestations in cats, but the overall incidence is unknown. Flea infestations are a common reason why cats present to a veterinarian.

Geographic distribution Relative humidity is the most important factor for flea survival. Temperatures between 68 and 86 degrees Fahrenheit with a relative humidity of less than 70 percent are ideal for flea infestation. Low temperatures (below 32 degrees Fahrenheit), as well as very hot or dry climates, are less favorable for flea development.

Clinical signs (primary, most to least frequent, scientific term, synonyms) Pruritus (itch) manifested by licking, biting and scratching (often associated with flea allergy or fleabite hypersensitivity), Alopecia (hair loss), Erythema (red skin), Miliary dermatitis (small red bumps in the skin caused by inflammation).

Clinical signs (secondary, most to least frequent, scientific term, synonyms) Presence of tapeworm segments (“rice grains” or “sesame seeds”) under tail, around anus or in feces due to Dipylidium caninum, Anemia (blood loss), fleabites on humans sharing household with heavily infested pets, other clinical signs less common but related to the diseases that fleas may transmit.

Causes (scientific, common term) Ctenocephalides felis (cat flea), Ctenocephalides canis (dog flea), Echidnophaga gallinacea (sticktight poultry flea), Pulex irritans (human flea).

Organ systems affected (most to least affected) Skin, Feces (due to tapeworm), Blood (due to flea anemia).

Diagnostic tests Visualize fleas on skin and within hair coat with flea combing or within environment. Visualize flea or black specks of digested blood shed by adult fleas to nourish larva, with flea combing. Visualize tapeworm segments in stool.

Differential Diagnosis Allergic dermatitis, Other external parasites, Ringworm (fungal infection), Bacterial infection.

Overview

Flea infestation is a common, but preventable condition affecting cats.

Most cases of flea infestation involve the cat flea, Ctenocephalides felis. Cats in multi-pet households, and especially cats that have outdoor exposure, or animals that visit boarding or grooming facilities are at increased risk for flea infestation.

Flea infestations may also be present in shelter or breeding facilities, where the density of cats is high. Fleas are more prevalent in warm, humid climates but are found worldwide.

Adult fleas survive only briefly off the cat (host) but may survive and reproduce for over 100 days if they remain on the animal. Scratching and self-grooming, as well as the application of insecticides, limit the longevity of adult fleas. The major portion of the life cycle occurs within the environment.

Eggs are laid in the hair coat but are easily dislodged. Larvae are released into the environment, feed on adult flea feces (blood), and move deep into carpets and cracks in wood floors. Pupae develop from larvae and are encased in cocoons, often within carpet fibers. Pupae may lie dormant for many months before adult fleas emerge and are very resistant to freezing, drying and insecticides. The entire life cycle may be completed in as little as 16 days, with an adult female producing as many as 40 to 50 eggs per day.

Fleas may be seen in the environment or on the pet. A flea comb may be utilized to trap fleas and flea “dirt” or flea feces (dried blood) on the pet. If a heavy infestation is present, humans may also receive fleabites during a feal infestation.

The flea's saliva may be irritating, and a single bite may trigger an allergic response in sensitive cats. This results in intense scratching, licking, chewing and loss of fur. Heavy flea infestations, especially in young or debilitated cats, may result in significant blood loss, or flea anemia, which may be life-threatening.

Fleas also serve as intermediate hosts for the tapeworm Dipylidium caninum, and segments (resembling rice grains) of the intestinal worm may be seen around the anus or in the feces. Other infectious diseases may also be transmitted by fleas.

Treatment

Home Care If a flea infestation is diagnosed or suspected, the environment should be thoroughly vacuumed, followed by disposal of the vacuum bag. Pet bedding should be washed or replaced. Area sprays containing pesticides are generally more effective than flea “bombs,” as the latter do not penetrate into cracks and crevices.

It is important to read the labels on all products carefully and consult with a veterinarian, as some products may be harmful to cats. Spot-ons, sprays and powders are available topically to kill adults and eggs.

Environmental products are designed to kill eggs, larvae and emerging adults. Depending on the environment and climate, repeating indoor treatment, as well as outdoor treatment, may be necessary.

Professional Care A veterinarian can prescribe a safe and effective treatment for on-pet use. All in-contact animals in the household should be treated.

Action Diagnosis and development of a treatment plan should be made by a veterinarian. Products should be used under the direction of a veterinarian when young, old, sick or debilitated cats are involved.

Outcome With appropriate treatment, cats are likely to have full resolution of their signs. The routine, prophylactic use of feline-labeled flea-control products will help prevent re-infestation.

References/Additional Readings

Scott, D.W., Miller ,W.H., Griffin C.E. Parasitic Skin Diseases. In: Kersey, R., DiBeradino, C., eds. Muller and Kirk's Small Animal Dermatology. Philadelphia: W.B. Saunders, 2001; 490-500.

Dryden, M.W. The Cat Flea: Applied Biology. In: Guaguere, E, Prelaud P, eds. A Practical Guide to Feline Dermatology. Merial USA, 1999; 8.1-8.6.

Author

Jeanne B. Budgin, DVM

DACVD

Editor

Steven Hansen, DVM, MS, MBA

DABVT, DABT

© 2007. The American Society for the Prevention of Cruelty to Animals (ASPCA)