Heartworm Disease: Your Cat Is At Risk Too

Posted on: 10 November 2015


If you thought that heartworm disease affects only dogs, think again. Cats are also at risk for this damaging and potentially deadly disease. The disease progresses and presents itself with some differences between the two species, and there is no approved treatment for feline heartworm disease. Prevention is the only effective course of medicine for protecting your feline friend. 

All Cats Are At Risk

Feline heartworm disease has affected cats in all of 50 states. Every case of heartworm disease begins with a single bite from an infected mosquito. When the mosquito bites a cat, heartworm larvae are deposited into the cat's body, where they enter the bloodstream. Since mosquitoes can enter your home through torn screens, open doors, windows and vents, even your strictly indoor cat is at risk.

Disease Differences In Dogs and Cats

There are differences in how heartworm disease affects dogs and cats. In both species, the heartworm larvae migrate through the bloodstream toward the lungs. In dogs, the heartworms continue to mature to adulthood, and they reproduce and settle in the dog's heart. An infected dog can harbor large numbers of the spaghetti-like worms in its body. Because cats are not ideal hosts for heartworms, most of the heartworms fail to reach adulthood. A cat that is afflicted with heartworm disease typically harbors zero to three adult heartworms in its body. This makes heartworm disease detection through blood antigen testing unreliable in cats since the antigens that produce positive results are generated only by adult female heartworms.

Other key differences between canine heartworm disease and feline heartworm disease include the following:

  • An adult heartworm lives two to three years in a cat's body, whereas the lifespan for an adult heartworm in a dog's body is closer to five years.
  • An adult heartworm in a dog grows to a length of 12 to 14 inches, and an adult heartworm in a cat reaches 5 to 7 inches in length.
  • Due to the smaller size of a cat's blood vessels, the presence of even one heartworm can have devastating consequences.

The Inflammatory Response of Feline Heartworm Disease

Heartworm associated respiratory disease, or HARD, is the term used to describe the effect of feline heartworm disease on the infected cat. When the heartworm larvae enter the cat's lungs, their presence incites an inflammatory response in the lungs. As the immature heartworms die, the inflammation is further exacerbated. Signs and symptoms that present with this inflammation include the following:

  • Coughing
  • Vomiting
  • Difficulty breathing
  • Rapid respiration
  • Lethargy
  • Decreased appetite

The inflammation inflicts damage to the lung's structures, including the arteries, alveoli, and bronchioles. HARD is essentially a lung disease that develops as the result of feline heartworm disease. Some of the presenting signs mimic those of feline asthma or other respiratory diseases, which can further complicate attaining an accurate diagnosis. Severe inflammatory responses that result from a heartworm's death can lead to the affected cat's sudden death.

Protect Your Pets

Fortunately, feline heartworm disease is preventable in the same manner as canine heartworm disease. There are several product alternatives to prevent heartworm disease in your cat. Most of the products are administered orally on a monthly basis, and some of them also provide added protection for your cat against other parasites, such as intestinal parasites, fleas or ear mites. Heartworm disease is no longer a topic of discussion that is exclusive to dog owners. Discuss a heartworm prevention program for you cat with your veterinarian, one like University Pet Hospital.