Heartworm in cats is a mosquito-borne parasitic infection that can have life-threatening complications. Although cats are NOT a natural host for heartworm and are less likely to get infected than dogs, heartworm prevention for cats is still generally recommended since they still have a chance of getting infected and sustaining systemic complications from heartworms.
Furthermore, there is NO FDA-approved heartworm treatment for cats. In this Sploot Vets guide, we talk about heartworm prevention for cats and when surgery may be considered as heartworm treatment for cats, depending on the case.
Quick Facts About Heartworm in Cats
Similar to dogs, cats can get heartworm from infected mosquitoes, which carry the heartworm larvae or microfilaria. Once the larvae are deposited into the cat’s bloodstream, around 25% of larvae make it to adulthood. Cats are relatively more resistant to heartworm than dogs.
The heartworm larvae that do survive in a cat’s system will take around 6 - 7 months before maturing into adult heartworms, residing in the heart, lungs, and blood vessels.
Some of the most notable symptoms of heartworm in cats include:
- Shortness of breath
- Persistent dry coughing
- Lack of energy & unwillingness to exercise
- Reduced appetite & weight loss
- Vomiting (however, the vomit won’t contain heartworms, as these parasites live in the bloodstream and heart—not the digestive tract)
→ Learn more - Heartworm in Dogs & Cats: Symptoms, Diagnosis & More
A. Heartworm Prevention for Cats
Do Cats Really Need Heartworm Prevention?
Yes, the American Heartworm Society recommends that pet parents provide their cats with year-round heartworm preventatives. Even though cats can resist heartworm better than dogs, they are still at risk of getting infected.
In addition, while the worm burden in cats is typically lower than in dogs, cats tend to have smaller bodies and narrower blood vessels, which can sustain significant complications from heartworm larvae or a few adult heartworms. A few examples of heartworm complications that are common in cats include:
- Heartworm-associated respiratory disease – significant lung inflammation and respiratory issues from immature worms (even if the worms don’t reach adulthood)
- Sudden death from an intense immune response – a small number of heartworms can trigger a severe immune reaction in cats, sometimes leading to sudden collapse and death without prior symptoms.
Heartworm prevention in cats involves the use of heartworm preventatives that are formulated for cats and heartworm testing:
- Heartworm preventatives for cats – These are oral or topical medications that are given every 30 to 60 days, depending on the brand, to eliminate heartworm larvae that can come from infected mosquitos.
- Yearly heartworm screening – This is generally recommended by The American Heartworm Society annually to help detect heartworms promptly.
- Heartworm screening before starting preventatives – This may be recommended for cats that have NOT been on preventatives before and are 7 months or older. Vets may also recommend heartworm testing if a cat misses their preventatives.
Kinds of Heartworm Preventatives for Cats
There are two main kinds of heartworm preventatives for cats. These include:
- Topical Heartworm Preventatives – these are prescribed liquid medications, applied between the shoulder blades every 30 to 60 days, depending on the brand. The medication is then absorbed through the cat’s skin. Depending on the brand, these can provide additional protection from fleas, ticks, and cat intestinal worms.
- Oral Heartworm Preventatives – these are prescribed oral medications (usually chewable) given every month. These can provide additional protection from fleas, ticks, and cat intestinal worms, depending on the brand.
What Is The Best Heartworm Prevention Medication For Cats?
The best heartworm prevention for cats is the one recommended by a trusted veterinarian. Vets take into account each cat’s individual needs.
In general, however, most cats best tolerate spot-on topical heartworm preventatives for cats because oral preventatives can cause stress or gut reactions in some cats.
Note: When using topical preventatives, make sure to follow instructions precisely, including the time needed for the formula to dry. Cats in multi-cat households must be separated while the topical heartworm preventative is drying so they cannot groom the formula off each other.
Is There A Heartworm Prevention Shot For Cats?
As of now, a heartworm prevention shot or injection is NOT available for cats. This is, however, available for dogs.
B. Heartworm Treatment for Cats
Can Cats Be Treated For Heartworm Disease?
As of now, there is NO FDA-approved drug therapy available to kill adult heartworms in cats. However, heartworm treatment for cats can take the form of symptom management. Vets may prescribe medication to manage inflammation caused by heartworms and treat Wolbachia, a symbiotic bacterium that heartworms carry.
Can Heartworms Be Removed From Cats?
In rare cases, surgery may be considered if there is a large number of heartworms that are causing severe symptoms and can be located using imaging techniques.
Heartworm removal surgery for cats, however, has its risks, which will be weighed carefully by an experienced veterinarian.
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If you have any questions about heartworm prevention or treatment for cats, we're here to help! Sploot Veterinary Care provides all-in-one vet care, with primary care, urgent care, and emergency vet services, all under one roof.
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Visit one of our vet clinics in Chicago, Denver, & Colorado Springs! Our clinic doors are open 365 days a year, for extended hours.
Easily book an appointment online or through the Sploot Vets app. You can also call our team to arrange an urgent-intake appointment if needed.
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