Heartworm Disease

Heartworms, or Dirofilaria immitis, are filarial parasites that affect primarly canid species but can also affect other species as well. To learn more about heartworms in cats, go to our ‘Cats – Heartworms‘ link by clicking on the link. Heartworms are spread from dog to dog by mosquitoes. A mosquito must first pick up a heartworm larvae from an infected dog. Then the heartworm larvae develops and when the mosquito bites an uninfected dog, the larvae is passed along. This larvae then migrates over the next few months through the skin until it matures completely. It then makes a quick trip to the heart where it sets up shop.

Common symptoms of heartworm infection include coughing, exercise intolerance, weight loss, difficulty breathing, and collapse. Most commonly, however, dogs that have heartworms are asymptomatic, which means that they look and appear normal. Although the name is somewhat misleading as heartworms live in the heart, they commonly cause most of their problems in the lungs and other organs. Heartworm babies (microfilaria) circulate in the blood and end up causing inflammation in the lungs, liver, spleen, kidneys, and just about any other organ in the body. We recommend that ALL heartworm positive dogs have a proper workup (bloodwork and x-rays) to correctly identify their ‘stage’ of the disease and be treated for their heartworms. After staging, we will be able to give a more accurate prognosis and appropriate treatment for the infection. Our veterinarian recommends yearly heartworm testing for all dogs but especially for those who are outside. Before any dog older than 6 months can be placed on heartworm prevention, they must show evidence of a heartworm test within the past year.

Most heartworm preventatives are flavored monthly tablets that also deworm for intestinal parasites. At our hospital, we recommend Interceptor or Sentinel as a heartworm preventative. If you have any questions about heartworm prevention, please don’t hesitate to call!

IMPORTANT NOTICE!!! – Heartworms are fairly common in North Carolina and it is very common for us to see heartworm positive dogs in our hospital. As there is no such thing as an outside only mosquito, we can only make one recommendation for heartworm prevention. KEEP YOUR DOG ON HEARTWORM PREVENTATIVE!!!