All pets that are not on year-around heartworm preventive medicine are at risk because the disease is spread by infected mosquitoes.
Pets diagnosed with heartworms cannot thrive without immediate treatment. Heartworms are parasites found in the heart and the main blood vessels of the lungs of infected dogs. They can and do live in the hearts of cats, but a cat’s heart is not the most ideal organ for a heartworm, so heartworms will typically find another place to live inside of your cat, including his or her brain. Infected dogs and cats may die unless heartworm infection is diagnosed and judiciously treated.

Heartworm infection can be easily prevented with routine medications such as chewable pills or topical treatments.

Symptoms & Testing

A heartworm test can be conducted in ten minutes on a dog simply by taking a few drops of blood and using a quick in-hospital test. If a pet tests positive for heartworms, a few clinical signs may or may not be present. Symptoms most commonly include coughing, trouble breathing, or evidence of heart problems. These can be symptoms of other disease as well. Many animals infected with the early stages of heartworm disease don’t show any symptoms. It is imperative to diagnose heartworm disease as early as possible. At Thrive, we recommend yearly screening for heartworm disease based on guidelines from the American Heartworm Society. To test for exposure to the worms in cats, a more conclusive diagnosis relies on analyzing both blood work and the cat’s symptoms. Many cats will have difficulty breathing or asthma-like symptoms, and chest x-rays can be taken as well to help evaluate cardiac conditions.


Dogs can be treated if a blood test shows a positive result, although treatment can take several months and can be extremely uncomfortable for the pet. At present, there is no approved treatment for heartworm positive cats.

Prevention Is Easy

Heartworm medications are readily available and there are a variety of quality brands in the market. Dosing is very easy and takes the form of either a monthly chewable pill, a topical treatment, or even an injection that we can give every six months. Some medications are dual purpose–preventing heartworms and serving as flea prevention. A few even control internal parasites.