Feline dirofilariasis

The cat must be recognized as a different entity than a dog when considering heartworm disease. The cat responds differently than the dog to larval migration, adult development, and therapy. As a result of these differences, the clinical signs shown by the cat and the therapeutic alternatives must be considered as unique to the cat. The diagnosis of heartworm disease in cats usually is more difficult than in the dog; therefore, the veterinarian must be more aware of the strengths and weaknesses of thoracic radiography, microfilaremia tests, and serologic tests than in the dog. Clinical signs in the cat are usually more vague and generalized than in the dog. When a diagnosis of heartworm disease in cats is made, the decision of which therapeutic regimen to use is a challenge. In many instances, the best treatment (except for supportive treatment) may be no treatment. Knowledge of the incidence of heartworm disease in an area may determine whether a veterinarian counsels a client to consider one of the preventive medications.