Many cat owners are surprised to learn that cats get heartworm disease too. Even a small number of worms — or immature larvae that never reach adulthood — can cause serious respiratory disease in cats, and unlike dogs, there is no approved treatment to eliminate adult heartworms in felines.
Because mosquitoes carry heartworm and readily come indoors, indoor-only cats are also at risk. We recommend year-round monthly prevention for every cat in Southern California's mild, mosquito-friendly climate, and we'll help you choose a product your cat will actually tolerate.
Our heartworm program
- Risk assessment for indoor and outdoor cats
- Testing when respiratory signs raise suspicion
- Monthly topical or oral prevention options
- Combination products that also cover fleas and intestinal parasites
What to expect
For most cats this is a prevention conversation during a routine visit: we assess risk, choose a monthly product your cat will tolerate, and set up refills and reminders. For cats with suspicious respiratory signs, testing involves bloodwork and often chest X-rays to look for the airway inflammation heartworm causes in cats.
Frequently asked questions
My cat never goes outside. Does she really need heartworm prevention?
Yes. Studies consistently find a meaningful share of feline heartworm cases in indoor-only cats, because infected mosquitoes come indoors. One monthly topical dose covers this risk — small insurance against an untreatable disease.
What does heartworm do to cats?
In cats, even immature worms trigger intense airway inflammation — coughing, wheezing, and vomiting that's frequently misdiagnosed as asthma. A small number of adult worms can cause sudden collapse. Cats aren't small dogs here; the disease behaves differently and worse.
Why can't feline heartworm be treated like canine heartworm?
The drug used to kill adult heartworms in dogs is not safe in cats, so there is no approved feline treatment — care is limited to managing inflammation and hoping worms die naturally without a crisis. That's why prevention is the entire strategy for cats.
Ready to schedule?
Request an appointment at our Glendale clinic or call our team — we serve pets and their people across the surrounding communities.