Heartworm Disease in Cats

By: Talin Seta Shahinian

You may have heard more about dogs having heartworm, but cats can suffer from it too. Also, the medication used to kill heartworm in dogs is toxic to cats, so they can’t be treated with it. Therefore, prevention is the best defense against heartworm disease. Here’s some more information about heartworm disease and what you can do to protect your cat.

What is Heartworm Disease?

Heartworm disease is a serious pet illness that can result in severe lung disease, heart failure, other organ damage and can even cause death in cats. Mosquitoes cause heartworm disease in cats. The parasitic worm Dirofilaria immitis gets transmitted to your cat by a mosquito bite. Keeping your cat indoors only lowers the risk, not eliminates it, as mosquitoes are certainly pesky little creatures that often find their way indoors.

What Are the Symptoms of Heartworm Disease?

The most common symptoms include:

  • Coughing.
  • Labored breathing.
  • Rapid breathing.
  • Lethargy.
  • Decreased appetite.
  • Weight loss.

These symptoms are due to heartworm disease’s effect on the cat’s lungs. Typically, cats only have one or two heartworms, but that’s enough to make their immune systems go into overdrive in an attempt to protect themselves. The immune response is a reaction to the presence of immature worms in the cat’s lungs or fragments of adult, dying heartworms present in the blood vessels that flow into the cat’s lungs. This process leads to inflammation within the cat’s lungs. The feline lung disease HARD (heartworm-associated respiratory distress) can develop due to heartworms.

How Is Heartworm Disease Diagnosed?

If your cat shows symptoms, he will be given an antigen test. However, that’s not foolproof, as cats can have false-negative test results. The American Heartworm Society recommends an additional blood antibody test for symptomatic cats. If those results indicate the high probability of heartworms, further tests are performed to ensure the diagnosis. Chest X-rays to examine the lungs and an ultrasound of the heart are recommended. This is because a positive antibody level can also remain present after heartworms have died, indicating that the cat had a past heartworm infection.

How Is Heartworm Disease Treated?

Feline heartworm infection is not directly treatable. It can only be managed. An anti-inflammatory medication, such as the Corticosteroid Prednisone, is usually prescribed. The treatment must be continued for two to three years until the adult worms have died and the cat’s lungs are clear.

Can Heartworm Disease be Prevented?

Preventive medication for heartworm is highly recommended, as it can protect your cat from ever getting heartworm in the first place. Please keep all your routine veterinary visits, and make sure to keep all your kitty’s shots and vaccines up to date to ensure that your cat won’t have to suffer through a bout of heartworm. While most cases aren’t fatal, this disease can progress and could end up in the loss of your beloved fur baby. It’s best to give her the best defense you can, for both your sakes.

If you live in NW Wisconsin, Purple Cat Mobile Vet Clinic is here to help you keep your cat healthy and happy. We’re a high-quality, high-volume, low-cost spay/neuter clinic. We see cats exclusively. Scheduling information is available on our www.purplecatvet.com website. You can also check out our Facebook page for more helpful information on all things feline!


All cat spay/neuter appointments are made on this website. We post new clinic dates 6 weeks ahead of time. Check back often if you do not see a date that works for you.

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