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September 28, 2022 |0 min read

Cat Heartworm: Causes, Prevention & Treatment

Written by

Sharilyn Vera

Heartworm disease is a serious and potentially fatal illness that affects pets worldwide. Generally, it is caused by mosquitoes that are infected with the worm parasite Dirofilaria immitis, which causes severe lung disease, heart failure, and damage to most body organs.

So, can cats get heartworm? Yes, but since it's a lot simpler to shield cats from the infection than treating the condition, we recommend you partner with a professional veterinarian to choose the best preventative care for your feline friend.

While the condition is less common in cats than in dogs – with only 5-20% infected, cats have fewer treatment options and may experience severe effects. Moreover, the medication used to cure dogs with heartworm infections don't apply to cats, making prevention the primary option to protect your cat from heartworm infections.

You can also ensure your feline friend is safe from this fatal disease by understanding and being mindful of the causes and signs of heartworm disease. To provide insight, we will discuss the causes and transmission of heartworm disease in cats, as well as prevention measures and means of treatment.

Is It Common for Cats to Get Heartworm?

Studies have shown that around 15% of cats, whether they live indoors or outdoors, have been infected with heartworm disease. However, cats are more resistant to infections; therefore, a small percentage of infected cats develop adult heartworm infections, where only 1 to 3 worms can be present.

Most cat infections, like those caused by the feline immunodeficiency virus, don't seem to increase the chances of feline heartworm infections. The major cause of heartworm infection is through a mosquito bite which carries heartworm larvae. Even though the development of heartworm disease in cats follows the same pattern as that of dogs, cats have smaller hearts and blood vessels, allowing the  infection more opportunity to cause greater damage to the cat's health.

What's more, cats are more reactive to heartworms than dogs, which causes lung inflammation – leading to poor blood oxygenation.

Can Cats Survive Heartworms?

Despite the name, heartworm infection in cats doesn't primarily attack the heart but the lungs. In some instances, cats can survive heartworm infections for a long time before it becomes fatal or succumbs to a second feline disorder. In very severe cases, there is potential it may become fatal. 

Most cats have a strong immune response that can eliminate the parasites, but even if your cat can clear the parasite, signs commonly associated with the disease might still be present. In most cats infected by mosquitoes, the heartworm larvae may mature and move – leading to numerous overt signs. So, heartworm prevention for cats is as important as treatment.

Do Cats Need Heartworm Treatment?

As mentioned earlier, cats are less likely to be infected by heartworms, and some infections might resolve on their own. But if your cat has developed heartworm disease, it means that their health is at risk, so it's important to seek monthly heartworm prevention to avoid new infections from developing if your cat gets infected by a mosquito again.

Heartworm in cats can be severe in some cases and damage the respiratory system. The infections can also affect your cat's immune system, leading to symptoms like: 

  • Coughing 
  • Wheezing reathing problems 

In severe cases, the worms can migrate to other areas in the body, like the brain, eyes, and spinal cord.

How Can I Prevent Heartworms from Infecting My Cat?

The good news is that it's pretty simple to prevent heartworm in cats. You can administer plenty of safe, efficient, and simple heartworm preventives to keep your cat safe and free from heartworms. These medications are generally affordable and available in either oral or topical form. It's recommended to administer these heartworm preventive medications year-round, whether your cat stays indoors or outdoors, especially if they live outdoors or in areas where the disease is more common, like in places where mosquitoes are highly present.

As one tip, consult your veterinarian to determine the best heartworm medication available for your cat. While the most ideal and effective way to protect your cat from an infected mosquito and other health-threatening parasites and elements is to keep them indoors, this alone is not enough to protect them from heartworms.

Heartworms are one of the most serious diseases affecting pet health, so you should arm them with heartworm preventative medication and constantly check for any tell-tale signs. Just taking a proactive approach can keep your cat safe from heartworms and other diseases.

Is There Any Treatment for Cat Heartworm?

Unfortunately, no drug is yet to be approved for treating cats with heartworms. Once the diagnosis is made, your veterinarian will guide you on the best action to monitor your cat's health and the ideal medications. If the case is severe, like cases where the worms are excess in the heart and blood vessels, you might have to attempt surgery to remove them.

Also, one of the most effective drugs vets use to treat cats is similar to the one used in dogs, but it has some significant side effects. To worsen things, if the adult heartworms die during the treatment, they will move through the pulmonary arteries to the lungs, where they can cause sudden death to the cat. Hence, the dilemma when cats are infected with heartworms.

One of three choices will be made:

  • Treat the cat with a drug made for dogs. Although this drug is effective, it can present significant side effects in cats, like lung failure or death. As a result, this approach isn't recommended.
  • Treat the symptoms and hope the cat can outlive the infection. Heartworms in cats can live for around two or three years, so several months of treatment are recommended. If the cat's health is serious, it will be treated with oxygen and cortisone to minimize the lung reaction. If necessary, drugs can be administered to eliminate fluid from the lungs (diuretics). But if the cat is stable, it will be treated with corticosteroids regularly or periodically. In most cats, this treatment minimizes the signs and improves their health. However, the chance of an acute crisis and death is always there.
  • Surgically remove the heartworms. This is usually the most recommended treatment for cats with serious heartworm infections. A specialist must conduct the surgery to avoid complications.  Studies show that around 40% of cats can die during or after this surgery, so surgical treatment is basically reserved for cats that suffer from severe heartworm disease.

What Are Some of the Symptoms of Heartworm Disease in Cats?

Heartworm symptoms in cats are challenging to spot because many cats infected with heartworms are asymptomatic. In addition, cats with heartworm disease are often misdiagnosed because the signs are similar to those in cats with asthma- like coughing and labored breathing. Some cats might even lack clinical signs at first, which is why tell-tale signs of heartworm disease significantly vary in severity.

Most noticeable signs become visible after the adult heartworm suddenly dies and causes acute issues within the cat or when worms migrate abnormally, leading to tissue damage. Still, there are some tell-tale signs you should keep an eye out for to stay on the safe side:

  • Coughing
  • Weight loss
  • Labored breathing
  • Reduced appetite
  • Wheezing
  • Vomiting

Considering the lack of present signs, it can seem impossible to tell whether your cat suffers from heartworm disease or not – which is why we recommend you take preventative measures.

Wrapping Up

Every cat is different, so you should work with your veterinarian to choose the best heartworm preventative care or treatment. Similarly, all preventative medications will differ, so you'll need to understand and follow the instructions to ensure you administer the medications correctly and protect your feline friend from further harm. Closely following the instructions is not only safe for your cat but you as well, especially if you're administering a topical product that can be spilt before, during or after administering the medicine.

Now that you know the risks and preventative measures, you can keep your feline friend safe and increase your cat's lifespan. So, if you witness any signs and symptoms that might indicate heartworm infection in your cat, consult your vet immediately to advise you on the best action to take. The American Heartworm Society is also an ideal resource for extra information on cat heartworm disease – so check it out for further insight.

For more information, feel free to call us anytime!


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Sources:
  1. Heart Worm Society. Heartworms in Cats. https://www.heartwormsociety.org/heartworms-in-cats
  2. MSD Vet Manual. Heartworm Disease in Cats -MSD Veterinary Manual. https://www.msdvetmanual.com/cat-owners/heart-and-blood-vessel-disorders-of-cats/heartworm-disease-in-cats
  3. Pet MD. Heartworm Disease in Cats | PetMD. https://www.petmd.com/cat/conditions/infectious-parasitic/c_ct_heartworm_disease
  4. VCA Hospitals. Heartworm Disease in Cats – Treatment. https://vcahospitals.com/know-your-pet/heartworm-disease-in-cats---treatment
  5. Vet.Cornell. Heartworm in Cats. https://www.vet.cornell.edu/departments-centers-and-institutes/cornell-feline-health-center/health-information/feline-health-topics/heartworm-cats
  6. Daily Paws. How to Spot, Treat & prevent Heartworms in Cats. https://www.dailypaws.com/cats-kittens/health-care/feline-parasites/treat-prevent-heartworm-cats
  7. Hills Pet. What is Heartworm in Cats? Symptoms, Diagnosis and Prevention. https://www.hillspet.com/cat-care/healthcare/heartworm-in-cats

Written by

Sharilyn Vera

Sharilyn is a proud cat owner, long time storyteller and researcher. Her work spans beloved podcasts, television shows, media outlets, and independent documentaries. She likes to strike a balance between education and comedy, which you can hopefully tell when you read her articles!

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