Heartworm Disease in Pets

Heartworm disease is responsible for infecting thousands of dogs and cats every year. This disease is potentially fatal yet completely preventable. Heartworm affects both dogs and cats, however, dogs do have an increased risk of developing this disease, especially those that live outdoors.

What causes heartworm disease?

Heartworm disease is caused by a blood parasite that is spread by mosquitoes. These heartworms migrate through the tissue until they enter the vascular system. Once infected, these nasty parasites reside and live on the right side of the lungs and pulmonary arteries where they obstruct the flow of blood to the heart affecting the rest of the body. By the time heartworms reach the lungs, they are mature and can grow to be as long as 14 inches. Hundreds could be living at one time.

Signs of heartworm disease in dogs

  • coughing
  • unwilling to exercise
  • shortness of breath
  • weight loss
  • fever
  • abdominal swelling
  • death

Signs of heartworm disease in cats

  • vomiting
  • lethargy
  • breathing difficulty
  • weight loss convulsions
  • death

How is heartworm disease diagnosed?

Diagnosis of heartworm disease in dogs and cats is commonly done by a blood test. X-rays and ultrasounds may need to be performed.

How is heartworm disease treated?

The treatment for heartworm depends on the seriousness of the disease. Many dogs need to be treated for the heart and lung disease prior to the heartworm treatment itself. To kill the heartworm, a series of injections are required. The side effects can last for up to two months. After the adult worms are killed, additional drugs are used to kill the microfilaria. The patient may need to be hospitalised.


Prevention is always better than cure, especially when it comes to heartworm disease. Heartworm is readily prevented through year-round heartworm preventative medications. Heartworm prevention for dogs and cats should be started from six to eight weeks of age and continued for the rest of their life. There are a variety of products available like

  • tablets,
  • chews
  • syrups
  • top spots
  • injections

Your veterinarian will be able to advise you on the most suitable product for your pet. Discuss heartworm treatment or prevention with your local Greencross Vets today.

Your nearest clinic: Undefined