Veterinary Medicine - November 2007 - (Page L13)

FLEA BITE FACTS Q&A treatment, including the following characteristics? I RAPIDITY OF FLEA KILL Dryden: While it appears that topical flea products should be able to kill fleas before they have the chance to bite or feed, this does not appear to be the case.4-6 This may be due to the decreasing activity of the residual insecticides over time after treatment. In fact, with most residual topical insecticides, residual activity often declines sufficiently before the next application for some fleas to live long enough (at least 24 hours) to produce eggs. That is why some manufacturers have added insect growth regulators to the formulations to kill the eggs that are produced. Blagburn: As mentioned previously, preventing fleas from biting and feeding serves two very useful purposes: it helps prevent the introduction of flea salivary antigens that can lead to flea bite hypersensitivity, and it prevents female fleas from consuming enough blood to commence egg production. The first is important in skin disease prevention, and the second helps break the life cycle and prevents the accumulation of environmental flea eggs, larvae, and pupae. Both topical and systemic flea treatments interfere with feeding and can, therefore, help achieve these goals if applied properly and regularly. Ihrke: Personally, I do not see this as an issue because the killing speed is a characteristic of each different insecticide. We need both topical and systemic flea control products that work rapidly enough to limit flea biting (and, thus, diminish the antigen load) and also prevent mating and egg production. However, a systemically administered product may offer better total body dispersal of the active agent. Griffin: Kill time depends on the product because each one varies in how fast it works and its efficacy over the labeled time to reapplication. Also, focal topical products take time to diffuse over the whole body, so they have a window before providing complete body protection. I WATER RESISTANCE Dryden: In my opinion, the residual activity of most topical insecticides can be compromised to some degree by bathing or repeated water exposure. Most of that effect likely occurs during the third or fourth week following application when insecticide residues are naturally at their lowest. The more lipophilic compounds, such as fipronil, appear to be the least affected by such exposure. An assumption could be made that compounds that act almost exclusively by systemic action would be minimally affected by bathing or water exposure. DeManuelle: Monthly topical flea control offers mild to moderate diminished efficacy for patients that require intensive bathing with a strong shampoo. Most of these products do not offer significant flea repellent activity. Griffin: Systemic products that work when fleas bite the pet are unaffected by bathing, rain, or swimming. Topical products raise some concern in how well they withstand frequent shampooing. This may also be true for systemic products that work by excretion Flea Trax I Systemic products may offer better total body dispersal of the active agent. I Stopping fleas from biting prevents the introduction of flea salivary antigens into the pet and it prevents female fleas from consuming enough blood to begin producing eggs. 13

Table of Contents Feed for the Digital Edition of Veterinary Medicine - November 2007

Veterinary Medicine - November 2007 Contents Leading Off The Veterinary Medicine Interview: Dr. Lila Miller Clinical Exposures Idea Exchange A Challenging Case: Uveitis and Secondary Glaucoma in a Cat Is it Immune-Mediated Neutropenia? Pimobendan Treatment in Dogs with Congestive Heart Failure CE Form Product Preview Advertiser Index Marketplace/Classifieds Mind Over Miller Special Supplement by Lilly: Flea Bite Facts Q&A

Veterinary Medicine - November 2007

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