Part 2 - Cats get Heartworms too!

Yes, Cats DO get heartworm disease.  Here's what you need to know: Part 2


Now that you understand that heartworm disease is a potentially life-threatening condition to your indoor cat from Part 1 of this series (, let’s cover the symptoms to watch for as well as preventative measures that you can take.

Signs of heartworm disease in cats can be very subtle or very dramatic. Symptoms may include coughing, asthma-like attacks, periodic vomiting, lack of appetite, or weight loss. Occasionally an affected cat may have difficulty walking, experience fainting or seizures, or suffer from fluid accumulation in the abdomen. Unfortunately, the first sign in some cases is sudden collapse of the cat, or sudden death. In many cases, the inflammation from the adult worms or the immature larvae leads to a respiratory disease called heartworm associated respiratory disease (HARD). Unfortunately, HARD can be difficult to diagnose because many cats do not show symptoms and because the symptoms may be confused with feline asthma or some other bronchial disease. And, in some cats, a heartworm infection may disappear spontaneously, possibly because a sufficiently strong immune response which can kill the parasite has developed. In most cases, the infection will progress steadily displaying clinical signs that may mimic the indications of many other feline diseases.


The initial testing for heartworm in cats includes an antigen and antibody test.  This is different than testing in dogs, because cats are much less likely than dogs to have adult heartworms.  If these tests are positive, a complete work up typically involves a complete blood count and blood chemistry profile, chest X-rays, a test to determine whether the patient’s blood contains antibodies to the parasite and a test to see whether adult heartworm proteins are present in the blood. Ultrasound imaging may also may be able to detect the presence of heartworms in the heart or pulmonary vessels. Dr. Dwight Bowman, DVM, PhD, a professor of parasitology at Cornell University’s College of Veterinary Medicine warns that unfortunately, heartworm disease in cats—unlike the condition in dogs—is untreatable. In an acute case of the disease, a cat may die suddenly.


Cats with signs of heartworm disease may require additional supportive treatment in the form of intravenous fluids, oxygen therapy, bronchodilators (which expand the air passages of the lungs), cardiovascular drugs or antibiotics. Surgery may be required to remove the worms if heartworms are detected via ultrasound or X-ray.


Heartworm preventative therapy is safe, easy and inexpensive and when administered properly can be extremely effective. Whew! Finally some good news! There are a variety of options for preventing feline heartworm disease including medications such as selamectin, milbemycin and ivermectin (administered monthly). It is recommended that heartworm preventatives be started before kittens reach 9 weeks of age. Cats over 6 months old should be tested for heartworms prior to starting prevention each year. The key to remember here is that you, the pet owner, can provide year-round protection to make sure your cat is guarded against this dangerous disease, especially in the warm, muggy sections of the US where mosquitoes proliferate. By keeping as many cats free of heartworm disease, we will take them out of the host population and reduce the risk of disease in the overall population. Preventatives are extremely cost-effective especially when you consider what it would cost you to treat your cat if they were to be infected or far worse, you could ultimately lose your pet.

Be sure to discuss prevention with your veterinarian at your cat’s annual check-up. Know the truths about heartworm and protect your cat 12 months a year!