April 23

Did you know that heartworm disease can lead to your beloved furry family member’s death?


National Heartworm Awareness Month, observed in April, aims to bring awareness to all pet owners about the deadly heartworm disease and how they can prevent and cure it.

Heartworm disease, which can occur in cats and dogs, is caused by a parasitic worm living in the heart, lungs and associated blood vessels, causing severe lung disease, heart failure and damage to other organs in the body of cats and dogs.

Dogs are a host of heartworms, meaning they can grow and reproduce in the animal, while cats are a dead-end host, meaning the worms cannot reproduce in the animal. Most cats are infected with only a few worms and may not be fully mature, though the disease can be just as deadly for cats as it is for dogs.

How is heartworm spread to cats and dogs?

Mosquitoes spread heartworm disease – heartworm larvae are found in the bloodstream of infected dogs. Mosquitoes pick up the larvae of the heartworms when feeding and then transfer them to other animals. The larvae then grow and mature into adult worms.

What types of heartworm prevention are available?

It is essential to consult your veterinarian before starting any preventative treatments. Several types of prevention are available for dogs and cats, including monthly oral prevention, which kills immature worms. Heartworm preventives must be administered strictly on schedule as, unfortunately, in as little as 51 days, heartworm larvae can mature to the point where prevention is no longer effective. Those worms then grow into adults, which causes heartworm disease.

What are the symptoms of heartworm disease in pets?

The most common signs in dogs are coughing, tiring quickly, collapse or fainting episodes, decreased appetite and weight loss. Many dogs, however, show no signs at all early on. Later in the infection process, heart failure can occur, and this is often displayed as a distended abdomen full of fluid. If a dog has large numbers of worms late in the disease, it can cause complete blockage of main arteries, which is fatal unless emergency surgery is performed to remove the worms physically. Cat heartworm disease is less obvious, with one common sign being a cough.

What’s involved in testing for heartworm disease?

Early detection is critical to treating heartworm disease successfully. However, because many dogs show no signs during early infection, a blood test is required to indicate whether an animal is infected. Therefore, all dogs should be tested annually for heartworm infection, and this can usually be done during a routine visit.

Because most cats are infected with only a few worms and may not be fully mature, heartworm infection in cats is more complicated to detect than in dogs. The preferred method for testing is an antigen and an antibody test; your veterinarian may also use x-rays or ultrasounds to look for heartworm infection.

How is heartworm disease treated, and with what medications?

If your dog tests positive for heartworm disease, there are several steps to treatment:

  • Your dog’s normal physical activities must be restricted as soon as the diagnosis is confirmed because physical exertion increases the rate at which the heartworms cause damage to the heart and lungs.
  • Before heartworm treatment can begin, your dog’s condition may need to be stabilised with appropriate therapy. This is more common if your dog has pre-existing conditions.
  • Once your veterinarian has determined that your dog is stable and ready for heartworm treatment, they will recommend a treatment plan involving several steps.
  • After treatment, your veterinarian will perform a heartworm test to confirm that all heartworms have been eliminated.

Cats have no treatment to eliminate heartworms, so prevention is essential for felines. The only option for cats is to provide treatment for their symptoms.

What’s the prognosis for heartworm disease?

With treatment, dogs with mild or no clinical signs of the disease have an excellent prognosis; even dogs with severe illness or heart failure do well in most cases. The main factor in how dogs fare during treatment is whether their activity is adequately restricted. If heartworm disease is untreated, the dog will continue to experience damage to his heart and lungs, and ultimately it will be fatal.


It’s everywhere!
Heartworm disease has been diagnosed in Australian states.
They look like spaghetti.
Mature heartworms look like long strands of spaghetti.
Dogs are more susceptible.
Dogs can have hundreds of heartworms in their bodies.
We need to act fast.
In most cases, the treatment often comes too late to cure the animal fully.
Decreased appetite might be a sign.
If your cat or dog is not eating well, it might indicate heartworm disease.