Developing integrated flea control for cats
Flea species associated with catsand their medical implications While several flea species have been found on cats in North America, only Ctenocephalides felis felis, the cat flea, occurs with enough regularity to be of considerable importance. The cat flea is the cause of severe irritation in cats, being responsible for the production of allergic dermatitis. The cat flea can also serve as the vector of typhus like rickettsia and is the intermediate host for filarid and cestode parasites.
Flea allergy dermatitis is an immunologic disease in which a hypersensitive state is produced in a host as a result of the injection of antigenic material from the salivary glands of fleas. The condition is found worldwide and is a major cause of feline miliary dermatitis. Since fleas feed exclusively on the blood of their host they can cause iron deficiency anemia or even death in heavy infestations. Murine typhus, caused by the organisms Rickettsia typhi and R. felis, is a febrile disease characterized by development of headaches, chills and skin rashes, with infrequent involvement of the kidneys and central nervous system. The cat flea is now a recognized vector of this disease in the United States. Dipylidium caninum, the common intestinal tapeworm of cats, develops as a cysticercoid in the cat flea. The cat flea is now considered the vector of Bartonella henselae among cats. Bartonella henselae is the causative agent of cat scratch disease in humans.Flea migration Once cat fleas acquire a host they feed rapidly, mate and begin egg production within 24 to 48 hours. Cat fleas remain on the host, laying 40 to 50 eggs per day within the pelage. Shortly after deposition eggs fall out of the hair coat and are distributed into the premises anyplace the flea-infested cat has access. Adult cat fleas are considered permanently host-associated ectoparasites. Since reproduction occurs on the cat, interruption of reproduction can be accomplished on the cat.
Most insecticides do an excellent job of eliminating existing fleas from the cat during the initial application. The problem is that reinfestation is a common occurrence. Historically, flea control was achieved through repeated application of short-acting, on-animal products and application of insecticides and insect growth regulators into the premises (IGRs). These programs were designed to kill existing fleas on the cat and reduce populations of developing and emerging adult fleas in the surrounding environment. The difficulty with this approach was getting cat owners to consistently follow treatment protocols. Because cat owner compliance was often poor, cats repeatedly acquired new fleas from the premises and infestations became a recurring problem.
The recent development of easily administered insecticides and IGRs with prolonged residual activity, have improved dramatically cat owner compliance and have helped to eliminate recurrent infestations.
These products work effectively at eliminating infestations because they either kill fleas prior to initiation of reproduction or reproduction is directly inhibited. While providing the cat immediate relief from fleas is one aspect of treatment, the other goal should be eliminating fleas before they can lay eggs. If flea products containing fipronil, imidacloprid or selamectin are be applied to cats at the prescribed dose and treatment interval there should be adequate residual activity for the next 30 days to kill most if not all newly acquired fleas within 24 to 48 hours before egg production begins. However, flea survival and reproduction do occasionally occur between applications. Infrequent product application occasionally occurs because of simple lack of compliance with label or veterinary instructions. While the inability of many cat owners to adequately apply traditional formulations has in large part been overcome with these new products, misapplication and therefore under-dosing does still occur. In addition, genetic variability of different flea populations means that none of these residual flea products are 100 percent effective against all cat flea strains between labeled reapplication periods.