How to prevent and treat heartworms in cats

Millions of Americans share their homes with pets and enjoy their affection and unfettered zest for life. However, pet ownership also comes with challenges when a pet becomes sick and one of the most frustrating ailments is heartworm disease.

Heartworm disease is a serious and potentially fatal illness in pets. Its name comes from foot-long worms that live in the heart, lungs and associated blood vessels. The worms are terrifically damaging, causing severe lung disease, heart failure and organ damage. The disease affects common household pets like dogs and cats, and other mammal species in the wild such as wolves, coyotes, and foxes.

Heartworm disease in cats

Heartworm disease in cats is an interesting scenario. Cats are not typical hosts for heartworms, and in fact most worms in cats do not even survive to the adult stage. Cats with adult heartworms present usually have only a few worms, and many cats have no adult worms at all.

This means heartworm disease is difficult to diagnose and is often missed. Keep in mind that even immature worms can cause significant damage, and traditional medicine used to treat heartworm infections in dogs cannot be used in cats. Prevention is the only means of protecting cats from heartworm disease.

How are heartworms transmitted in cats?

Mosquitoes are the most prolific heartworm transmitters. They ingest immature heartworm larvae by feeding on an infected cat or dog. The larvae then develop for 10 to 30 days inside the mosquito. The next time the infected mosquito bites a cat, it injects the heartworm larvae, which then matures over a period of several months, eventually settling near the right side of the heart. It is here that adult heartworms form and in less than a year, most cats will show symptoms of the disease and it often becomes fatal very quickly.

Diagnosing heartworm disease

It is extremely difficult to diagnose heartworm disease in cats, as there are no definitive clinical signs verifying its existence. But that does not mean the disease isn’t present. You can stay aware by looking for symptoms including:

  • Difficult or labored breathing
  • Vomiting and coughing
  • Convulsions
  • Blindness
  • Lethargy
  • Anorexia or other weight loss
  • Fluid in the lungs
  • Sudden death


Treatment of heartworm disease

While heartworm disease cannot be cured, it can easily be prevented long before serious medical issues develop. Veterinarians strongly recommend that all cats receive monthly heartworm preventive medications in areas where mosquitoes are active.