Flea and tick control in the 21st century: challenges and opportunities.

Historically, veterinarians have told their clients that one flea is all that is necessary to produce and maintain the clinical signs of flea allergy dermatitis (FAD). Newer adulticides, such as fipronil, imidacloprid, nitenpyram and selamectin, have had a positive clinical effect on dogs and cats with FAD. However, data on flea feeding and the effect of these products on flea feeding bring into question the once perceived dogma of the single flea bite concept. Current data would indicate that the primary role of these insecticides in managing FAD is in rapidly reducing flea numbers and reducing flea feeding rather than preventing flea bites. Controlling tick infestations is important not only because ticks are nuisance parasites of dogs and cats, but also because they are vectors of a variety of bacterial and protozoal diseases. Achieving satisfactory tick control is often difficult due to unrealistic expectations of pet owners, to residual acaricidal properties of products that are often less than 100% and because of constant re-infestation pressure. Some of the most important factors veterinarians must be aware of are regional changes in tick distributions, our inability to control wildlife tick hosts and expectation differences between flea and tick control. These factors probably cause most real and perceived product failures.