Veterinary Medicine - November 2007 - (Page L5)

FLEA BITE FACTS Q&A topical, prevents feeding. The effect may be by repelling, incapacitating, or killing the fleas. The preferred product is the one that limits flea feeding the most, especially for flea allergic pets. Ihrke: Preventing feeding is crucial for flea allergic animals because flea salivary antigens are deposited into the skin each time a flea feeds. Dryden: The feeding activity of fleas is so rapid that for years I was doubtful that any insecticide could stop flea bites. Studies have now demonstrated that neither topical nor systemic insecticides can stop this initial biting and feeding.4-6 But systemically active insecticides appear to decrease blood feeding more rapidly and more profoundly than topically active insecticides.6 Blagburn: Both topical and systemic flea control products can affect flea feeding quickly and dramatically. However, neither will inhibit feeding altogether. Some systemic products can achieve greater than 90% flea control within three to four hours. Some topicals take a bit longer, achieving 80% to 90% efficacy within six to 12 hours. Studies demonstrate that the size of the blood meal taken by fleas is greatly reduced by both systemic and topical products. A corollary to reduced feeding is the introduction of less flea salivary antigen into the host. This reduces the likelihood of allergic reactions to fleas. “When cat fleas infest a dog or cat, most begin feeding within seconds to minutes, with upwards of 89% being blood fed within five minutes.” —Dr. Michael Dryden does this issue affect your recommendations regarding application frequency? Dryden: This is difficult to answer. There are many possible variables, such as the level of infestation, hair coat length and density, where the pet’s weight falls within the unit dosing range, and exposure to water or bathing. However, given all these variables, it has been my perception that heavy flea infestations can impact the performance of topical flea products. This may be real or perceived, but I often recommend either increasing the frequency of application from four weeks to three weeks or administering short-acting nitenpyram. The orally administered and systemically active nitenpyram does not seem to be affected by flea numbers. Blagburn: I agree that this is a difficult question because efficacy and residual activity of topical products vary. In the laboratory, efficacies of 100% can usually be achieved in 12 to 24 hours and usually maintained above 90% for 28 days. In reality, wetting, bathing, the types of shampoos used in bathing, the weight of the animal, and chemistry of the active ingredient and formulation can all affect Flea Trax I Each time a flea feeds, flea salivary antigens are deposited into the skin. I Preventing feeding is critical for all flea-infested dogs and cats, especially those with flea allergy dermatitis. I Systemic products appear to decrease feeding more rapidly than topical products. I The size of the blood meal taken is greatly reduced by both systemic and topical products. How long do flea products maintain efficacy in heavy flea infestations? How 3 5

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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