The Heart of the Matter

Heartworm is a potentially serious, but preventable condition, caused by the infection of parasitic worms, which live in the heart, and in blood vessels.

Heartworm has been reported in Canada, with the highest concentrations in Southern ON, but with occurrences in Atlantic provinces, including Nova Scotia. It primarily affects dogs in this region, but can live within both wild and domestic animals.


Spread of the disease is dependent upon transmission via the mosquito. When a mosquito takes a blood-meal from an infected animal, the mosquito ingests microfilariae, which are tiny, immature heartworms.  Within the mosquito, the microfilariae develop into an infective larval stage. Once the mosquito bites, for example, a dog, larvae can be passed into the dog’s bloodstream, through the bite wound, thereby causing infection. Over a period of time, ranging from months to years (but usually within six months), the larvae develop into adult worms which live within the vessels surrounding the heart, including the pulmonary artery, which circulates blood around the lungs. These adult worms also continue to mate, and produce another generation of microfilariae.

Signs and Symptoms:

Dogs often don’t display symptoms until later stages of the disease, when the dog may exhibit coughing, exercise intolerance, lethargy, and weight loss.  At this time, the adult heart worms living in and around the heart have caused inflammation to the vessels, and can cause increased blood pressure from the worm burden. Heavy infections can cause congestive heart failure. Unfortunately, once the dog exhibits clinical signs, irreversible damage may have been done to the internal organs.


Testing and screening for heartworm is accomplished by a simple blood test, which is important for detection, early treatment, and reducing the spread of the disease. It can also be detected by ultrasound and x-rays, in advanced cases.  Please contact us at Full Circle to see what we’re doing to focus on early Heartworm detection.


Treatment options include both products to kill adult worms, followed by an antiparasitic, to kill the immature microfilariae.  There can be complications with treatment, as it is a multi-step process, not without risks; once again, prevention is the best route to keep your dog healthy during heartworm season.


Heartworm disease is highly preventable. These measures can be discussed with our vets here at Full Circle. You may want to consider travel plans, and lifestyle, and other factors with the vet when deciding on a preventative product.  Multiple options exist which, when used regularly, throughout mosquito ‘season’ are highly effective. Most preventative products are directed at eliminating microfilariae, which means that the disease can be interrupted, prior to adult worms developing, and before any damage can occur.

By: Patti, R.V.T


halloween puppy

Fun Halloween Safety Tips for Pets

Treats for everyone! Many human treats on Halloween are toxic to pets.

Read More
See All Articles

Last updated: November 24, 2020

Dear Clients,

With recent changes to restrictions on businesses, we can continue providing our full range of services, under certain restrictions. As our province enters the next phase of the reopening plan, we have some updates to share with you about our safety measures.

We are continuing to see all cases by appointment only including Canine Rehabilitation Services, Animal Chiropractic, TCVM Consultations, Bloodwork for Referral Services, Wellness Exams, Vaccines and more!



We are OPEN with the following hours:

- Monday to Friday: 10:00 am - 6:00 pm
- Saturday & Sunday: CLOSED

Thank you for your patience and understanding and we look forward to seeing you and your furry family members again!

- Your dedicated team at Full Circle Veterinary Alternatives Inc.