When people think of heartworm disease, they almost always think of dogs. But here’s something many pet owners don’t realize: cats can get heartworms too—and in some ways, the disease can be even more dangerous for them.
How Do Cats Get Heartworms?
Heartworms are transmitted through the bite of an infected mosquito. When a mosquito carrying heartworm larvae bites a cat, those larvae can enter the bloodstream and migrate to the heart and lungs.
Even indoor cats are at risk—mosquitoes can easily enter homes through doors, windows, or screens.
Why Heartworm Disease Is Different in Cats
Cats are not the natural host for heartworms, which makes the disease behave differently:
- Cats typically have fewer worms, but even 1–2 can cause severe illness
- The disease often affects the lungs more than the heart
- There is no approved treatment to eliminate adult heartworms in cats
This makes prevention absolutely critical.
What Is HARD?
Cats can develop a condition called Heartworm-Associated Respiratory Disease (HARD), which can mimic asthma or other lung conditions.
Symptoms may include:
- Coughing or wheezing
- Difficulty breathing
- Vomiting
- Lethargy
In some cases, the first sign may be sudden collapse or death.
Diagnosis Challenges
Heartworm disease in cats is not always easy to diagnose. Standard tests used in dogs may not detect infections in cats as reliably, making prevention even more important.
Prevention Is the Best Protection
Because treatment options are limited, prevention is the safest and most effective approach:
- Use monthly heartworm preventatives
- Maintain year-round protection, even indoors
- Talk to your veterinarian about the best product for your cat
Heartworm disease in cats is often underestimated—but it shouldn’t be. With no reliable treatment available, prevention is the best defense. A simple monthly preventative can protect your cat from a potentially life-threatening condition.