Can Cats Get Heartworm? What Every Pet Parent Should Know

Don’t let hidden risks harm your cat’s comfort and health.

Although not talked about as frequently, cats can and do get heartworm. It’s transmitted when a mosquito bites an infected animal, then bites your cat. Through this bite, heartworm larvae are transferred and find their way into the bloodstream.

Unlike dogs, cats are not natural hosts. While the mature worm burden is significantly less, don’t be fooled immature worms can still cause significant damage as they migrate to the lungs and heart. As they arrive in the pulmonary arteries and die off, they can create a severe inflammatory reaction. This often presents as serious respiratory symptoms.

When the few worms that do mature reach the end of their life cycle, they may trigger an anaphylactic reaction, which can be fatal.

Heartworm in cats is often difficult to diagnose because the symptoms mimic other common feline health issues. Signs are usually subtle at first, but can quickly progress. Pet parents may notice what looks like feline asthma attacks, upper respiratory issues, open-mouth breathing, vomiting, loss of appetite, and lethargy.

Cats can become very ill before a heartworm diagnosis is discovered. Blood testing, radiographs, and ultrasound are some of the tools veterinarians use to investigate.

Unlike in dogs, there is no treatment for feline heartworm. Sadly, the prognosis for cats diagnosed with heartworm is poor.

Just like with dogs, a blood test can screen for heartworm. Your veterinarian may recommend annual testing, even if your cat is on prevention year-round. While today’s products are highly effective, human error or rare product failure can cause a lapse in protection, creating a window for infection.

With Michigan’s milder winters extending mosquito season, the risk of heartworm in cats has increased. Year-round prevention is now the standard. Mosquitoes can also get into our homes, putting indoor cats at risk too.

Using a monthly topical preventative helps protect your cat from heartworm and offers added protection against fleas and ticks.