Canine External Parasites Study Guide

Overview and Clinical Importance

External parasites represent one of the most common reasons for veterinary visits in small animal practice. These ectoparasites cause significant morbidity through direct tissue damage, hypersensitivity reactions, and vector-borne disease transmission. The NAVLE frequently tests knowledge of parasite identification, life cycles, clinical presentations, and treatment protocols.

This study guide covers the three major categories of canine external parasites: fleas (Siphonaptera), ticks (Acari: Ixodidae), and mites (Acari: various families). Understanding the pathophysiology, diagnosis, and treatment of these parasites is essential for board examinations and clinical practice.

Section 1: Fleas (Order Siphonaptera)

Biology and Life Cycle

Ctenocephalides felis (the cat flea) is the most common flea species affecting both dogs and cats, accounting for greater than 90% of flea infestations. Despite its name, it is the predominant flea on canines in North America.