What is Heartworm?

Heartworms are an Internal Parasite That Cats and Dogs Contract via Mosquitoes

Mosquitoes transmit heartworm larvae between animals through their saliva. If the cat or dog takes their heartworm preventative within 30 days, the larvae will be eliminated.

If the pet is not protected, they will develop stage I heartworm disease.

The larvae travels through the bloodstream to the heart, where it spends about six months growing into an adult - which can reach 12 inches in length.

Left untreated, heartworm disease progresses to more advanced stages. Once the larvae have fully grown, the heartworms will start to breed, producing hundreds of offspring that start to take over the heart and blood vessels.

Just one bite can lead to serious disease. Thankfully, it's easy to protect pets with a heartworm preventative.

Keep cats and dogs protected against mosquito-borne heartworms.

Why Should Pet Parents Worry About Heartworm Disease?

Parasites are a health risk to all cats and dogs. Whether your pet likes to be at one with nature - or at one with the couch - they're likely to pick up parasites at some point.

But heartworms are their own horror story. These circulatory system scavengers are especially brutal. Pets can develop heartworm disease after just one skipped dose of their preventative.

There are over 1 million cases of heartworm disease in dogs across all fifty states. Cats are less susceptible to heartworm, but cannot be treated once infected.

With heartworm preventative, you can greatly reduce your pet's risk of...

  • Months of painful, expensive injections and hospitalization.
  • Severe lung disease and heart failure, which could leave permanent damage even after treatment.
  • Death, even with treatment in severe cases.

Heartworm disease is difficult to treat, and treatment is not always successful. But prevention is easy and affordable, and it's available as a tasty chewable tablet for cats and dogs.

What's the harm in one little bite?

Protect Your Pets Against Heartworm Disease

Keep cats and dogs protected with a heartworm preventative, available via prescription from your veterinarian. Save time and money when you get your pet's medication delivered to your doorstep with PetMeds®.

Heartgard Plus Chewables Heartgard® Plus Chewables
Simparica TRIO Simparica TRIO
Revolution Plus Revolution Plus
Interceptor Interceptor
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Frequently Asked Questions About Heartworm in Pets
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Do indoor cats need a heartworm preventative?
Heartworm larvae enter the bloodstream when your pet is bitten by a mosquito. Mosquitoes are usually outdoors in warm weather, but they can also be found indoors at any time of year in all fifty states.
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Can I skip doses in the winter?
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Is heartworm preventative safe for pets?
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Why does heartworm prevention require a prescription?

What if I have another question about heartworm disease? Learn all about heartworm disease and other pet health topics with our free Pet Health Advice center, or talk to your veterinarian if you have questions specific to your cat or dog.