Veterinary Medicine - October 2007 - (Page S1)

ECTOPARASITOLOGY SYMPOSIUM SUMMIT VetPharm ARTICLE 1 COMPANION ANIMAL TICK CONTROL BYRON L. BLAGBURN, COLLEGE OF ADVANCES IN MS, PhD VETERINARY MEDICINE • AUBURN UNIVERSITY • AUBURN, ALA. Ticks are important blood-feeding ectoparasites of dogs, cats, and people.1,2* Tick infestations can result in anemia, allergic dermal reactions, paralysis, and other forms of toxicosis.They also serve as efficient vectors for numerous disease agents.Ticks and mites (e.g., scabies mites and ear mites) are members of the order Acarina. The two tick families of interest in veterinary medicine are the ixodid, or hard ticks, and the argasid, or soft ticks.2 They differ in structure, ability to expand when feeding, and developmental cycles.The ixodid ticks are of primary interest in companion animal parasitology and are the focus of this article. Common ixodid tick characteristics are summarized in Table 1 (page 2). See pages 3 and 5 for photos of adult and immature ixodid ticks. Although similar in structure to mites, ixodid ticks are larger and possess a leathery shield, or scutum, on their dorsal surface.The scutum covers the entire surface of adult male ticks but only a portion of the dorsal surface of female ticks.The presence or absence of iridescent white or yellow patches on the scutum of adult ticks is useful in identifying the different species. Ticks with these colorful markings are called ornate ticks (e.g., Amblyomma, Dermacentor), and Supported by those without them are called inornate ticks (e.g., Rhipicephalus, Ixodes). Tick life cycles Ixodid ticks develop through four distinct life cycle stages: egg, larva, nymph, and adult.2 Ticks increase in size as they develop from larva to adult. Larvae, nymphs, and adults are similar in appearance but differ in size and the number of legs (larvae possess six legs; nymphs and adults possess eight legs). Larvae and nymphs, unlike adults, do not possess features of sexual dimorphism. Hard ticks that infest pets are referred to as three-host ticks because the larva, nymph, and adult stages use different hosts during their life cycles.The brown dog tick (Rhipicephalus sanguineus) is a notable exception in that all stages of R. sanguineus usually infest dogs. Consequently, it can be difficult to eradicate from kennels and homes. The numbers of hosts used by some ticks can be formidable. For example, the Eastern black-legged tick (Ixodes scapularis) may parasitize in excess of 100 different host species of reptiles, birds, and mammals.2 After each stage feeds to repletion, it drops from the host, molts to the next stage, and seeks a new host.This “on the host, off the host” cycle continues until the adult female tick drops © 2007 Summit VetPharm. All rights reserved. www.summitvetpharm.com 1 http://www.summitvetpharm.com http://www.summitvetpharm.com http://www.summitvetpharm.com

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

Veterinary Medicine - October 2007 Contents Leading Off The Veterinary Medicine Interview: Dr. Kevin Fitzgerald Toxicology Brief Idea Exchange Animal Sheltering in the United States: Yesterday, Today, and Tomorrow The Euthanasia Problem Offer Basic Behavior Counseling for Every Pet at Every Visit Promote and Perform Early Spaying and Neutering Assist Owners in Selecting the Best Pets for their Lifestyles Champion Animal Welfare in Your Community CE Form Product Review Advertiser Index Marketplace/Classifieds Mind Over Miller

Veterinary Medicine - October 2007

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