Myths and Facts About Heartworms in Dogs

You've probably heard a lot about heartworms. You may even be reluctantly feeding your dog those monthly medicated “treats" from your veterinarian (good job!). But you still may not be sure about what's fact and what's fiction when it comes to heartworm disease in dogs.

How do dogs get heartworm?

Much like the name implies, heartworm disease is caused by small worms (parasites) that enter your dog's bloodstream through the bite of a mosquito. Once inside, the tiny baby worm makes its way to the lungs and heart, slowly growing (up to a foot long) and causing blockages, breathing challenges, and even heart failure.¹

The good news is that heartworm disease is preventable, and in certain cases even treatable.² Below, we'll help clarify why heartworm prevention and testing are essential to keeping your pup's heart healthy and happy.

1. Myth: I don't need to worry about heartworm disease if my dog doesn't spend time outside.

Fact: Infected mosquitos can find ways to get inside your home. In addition, even if your dog only goes outside to use the bathroom, he or she can become exposed to an infected mosquito.³

2. Myth: Heartworm disease is not that serious.

Fact: Heartworm disease is a potentially fatal condition that can cause permanent damage or heart failure if left untreated.

3. Myth: Heartworm prevention isn't necessary.

Fact: The American Heartworm Society recommends year-round heartworm prevention, since leaving a dog unprotected at any time can put your pet at risk for the disease. Pills, topical treatments and even injectables can help prevent heartworms.² Be sure to also schedule routine visits with your veterinarian, keep mosquitos out of your house, and minimize mosquitos in your outdoor spaces.⁴

4. Myth: Heartworms are only an issue in the summertime.

Fact: While mosquitos may be more prevalent during warm weather months, they can appear during any season. Heartworm disease has also been confirmed in all 50 states.⁵

5. Myth: Heartworms are contagious.

Fact: Pets (and humans) can't catch heartworm disease from other pets. Heartworms can only be transmitted by mosquitos.⁵

6. Myth: My dog doesn't need a heartworm test if he or she is on heartworm prevention medication.

Fact: While heartworm disease is easy to prevent, it's easy to miss a dose. Annual heartworm testing, which can be part of your dog's annual checkup, can also ensure that your heartworm prevention medicine is working.²

7. Myth: Heartworm prevention is too expensive.

Fact: Heartworm prevention is much less costly than treating the disease. A year-round supply of preventives can cost about $60 - $180, depending on your dog's weight.¹

8. Myth: If my dog is diagnosed with heartworm disease, there's nothing I can do.

Fact: There are a few actions you can take to help your pup if they have heartworms, starting with taking them to the veterinarian to confirm the diagnosis. You can also:⁶

• Continue administering monthly prevention medication (learn more about how to give your dog medication)
• Limit their activity/exercise
• With your vet’s help, get your dog in a stable condition
• Follow your vet's treatment recommendations, which could include injections, hospitalization, pain medication, and/or lab work

9. Myth: Heartworm disease is untreatable.

Fact: Vets often treat heartworms with medication, though it can take weeks to months for the medications to fully work. In the meantime, however, your vet may be able to lessen some of your pup's symptoms and help them start feeling better. Successful treatment will depend on many factors,³ including:

• Severity of the disease
• Length of time heartworms have been present in your dog's body
• Your dog's age, breed, and weight
• Whether your dog has any additional conditions

10. Myth: Treating heartworm costs less than preventing it.

Fact: Preventing heartworm disease costs about $120 per year, whereas treating heartworms costs around $1,000.¹