Table: Diagnostic Tests, Clinical Signs, and Treatment for Heartworms in Dogs, Cats, and Ferrets

Diagnostic Tests, Clinical Signs, and Treatment for Heartworms in Dogs, Cats, and Ferrets

Host	–-–----------------Diagnosis (Test Utility)---------------------				Clinical Signs	Prevention	------------Treatment------------
	Microfilaria	Ag or Ab Test	Thoracic Radiographs	Echocardiography			Adults	Microfilariae
Dog	****	***** (Ag)	*** MPA, PA, RHE, PTE, PIE	**	Respiratory, weight loss, exercise intolerance, heart failure	Ivermectin, milbemycin, selamectin, moxidectin	Melarsomine, doxycycline, symptomatic treatment	Moxidectin^a, ivermectin + doxycycline, milbemycin
Cat	*	(Ag) ** (Ab)^#	** PA, PIE	****	Respiratory, vomiting, sudden death, heart failure	Ivermectin, milbemycin, selamectin, moxidectin	Symptomatic treatment;, doxycycline + ML, worm extraction	NA
Ferret	*	*** (Ag)	* RH	***	Heart failure, respiratory, sudden death, heart failure	Topical imidacloprid-moxidectin product labeled for cats and ferrets This product should be administered monthly at the recommended minimum dosage of imidacloprid (20 mg/kg), and moxidectin (2 mg/kg), by topical administration, regardless of indoor/outdoor status.	Symptomatic treatment (including corticosteroids) Possibly topical imidacloprid-moxidectin labeled for cats and ferrets	NA
^aImidacloprid-moxidectin is the only approved microfilaricide. * = rarely useful; = somewhat useful; * = moderately useful; ** = often useful; *** = excellent test; Ag = antigen; Ab = antibody; # = Ab-positive does not prove mature infection, only exposure/abbreviated infection; MPA = main pulmonary artery enlargement; PA = pulmonary artery enlargement; PTE = pulmonary thrombus/thromboembolus; PIE = pulmonary infiltrate with eosinophils; ML = macrocyclic lactone (macrolide); RH = right heart enlargement; NA = not applicable Adapted from McCall, JW. Clin Tech Small Anim Pract. 1998;13(2):112.