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Heartworm Disease in Dogs



In initial treatment, most patients are hospitalized as they receive administration of an adulticide designed to kill the adult heartworms. The microfilariae in the body can be eliminated with a monthly prophylaxis, which can be administered at home. For more severe cases, such as dogs experiencing thromboembolic complications (in which a blood clot that has formed breaks loose and travels through the blood stream to clot another vessel), hospitalization may be necessary for a longer period of time.


In some cases, a surgical procedure may be necessary to remove adult worms from the right heart and pulmonary artery by way of the jugular vein. This procedure is recommended if the infestation consists of a high number of adult worms.


Living and Management


Upon initial heartworm treatment, activity should be severely restricted for at least four to six weeks after administration of the adulticide. Severely affected dogs may need to be kept in a cage to limit activity. For dogs recovering from congestive heart failure, a moderately restrictive sodium diet is recommended.


An antigen test should be done four months after adulticide treatment to check for continued presence of the adult Dirofilaria immitis. If the test is positive, the adulticide treatment can be repeated, or a surgical procedure performed instead. Some dogs with persistent infestation may not require retreatment, depending on the patient’s age and severity of the disease. Older dogs, for example, may not be overly affected by mild recurrent worm infestations.




Routine heartworm prophylaxis (preventative) should be given to any at-risk dogs, for example those living in endemic regions, as directed by your veterinarian. This is essential to preventing heartworm infestation. There are a number of medical preventatives that are highly effective and commonly used. It is possible for reinfestation to occur if a prophylaxis is not regularly administered.