Heartworm Prevention in Alberta: Is Your Pet at Risk?

Many pet owners in Edmonton assume their dogs are safe from heartworm disease.

After all, our province is known for long, frosty winters and a short mosquito season. It's logical to think that fewer mosquitoes mean your furry family member is out of harm's way.

However, you might feel a bit of tension when you hear different advice.

Some sources suggest heartworm prevention in Alberta isn't a big deal, while your veterinarian insists on annual testing. It is tough to know who to trust when your neighbour’s dog seems perfectly fine without it.

You deserve an honest conversation about what we know, what is changing, and how we can work together to keep your pet healthy.

What Heartworm Disease Does to Your Pet

Before we look at the risks, it is important to understand what we are protecting.

Heartworm disease is caused by a parasite called Dirofilaria immitis. These worms live in the heart and lungs of infected pets and can grow up to 30 centimetres long.

The damage often starts silently. By the time you notice a cough or fatigue, the disease has usually progressed.

While treatment is possible, it is very hard on your pet and requires strict rest for months. This is why our veterinary team focuses on prevention as the foundation of a healthy life.

How Heartworm Spreads in Our Climate

Your pet cannot catch heartworms from another dog at the park. Infection only happens through the bite of an infected mosquito.

For the larvae to develop inside a mosquito, temperatures must stay above 14°C (57°F) for about two weeks.

Historically, Alberta’s cooler summers limited this window. This is why heartworm dogs in Alberta were once quite rare compared to those in Ontario or the United States.

However, our environment is shifting.

The Alberta Question: Why Low Risk Isn't No Risk

While Alberta isn't a "hot spot" for heartworm, uncommon doesn't mean impossible. Here are a few reasons why we recommend heartworm prevention in Edmonton:

• Travel: Many families take their pets to warmer areas like British Columbia or the U.S. A single bite during a road trip is all it takes. 
• Imported Pets: Many wonderful rescue dogs come to Alberta from regions where heartworm is very common. These pets can act as a source for local mosquitoes. 
• Changing Weather: Our summers are getting warmer and longer. We can't say for sure how this affects transmission, but the risk is certainly not decreasing. 
• Microclimates: Your specific neighbourhood might stay warmer than the city average, creating a perfect window for mosquitoes to spread the parasite.

Heartworm Prevention in Edmonton: Your Options

If you decide to protect your pet, you have several reliable options. Most heartworm prevention in Alberta is given monthly during the warmer months, typically from June through November.

These medications kill larvae before they can grow into adult worms. Common options our staff might suggest include:

• Oral Tablets: These often protect against other parasites, such as roundworms. 
• Topical Treatments: These are applied to the skin and can also guard against fleas and ticks. 
• Injectable Protection: Some options provide long-lasting coverage so you don't have to remember a monthly dose.

Please remember that your pet must have a negative blood test before starting any medication. Giving prevention to a pet that already has heartworms can lead to a dangerous reaction.

When Heartworm Becomes an Emergency

• Caval Syndrome: This is a severe, life-threatening emergency in which a large number of adult heartworms physically block blood flow through the heart. Symptoms include sudden-onset extreme lethargy, pale gums, laboured breathing, or dark/coffee-colored urine. 
• Reaction to Prevention: If a dog with an existing adult heartworm infection is given preventive medication without first being tested, it can trigger a severe, potentially fatal systemic reaction as the microfilariae (larvae) die suddenly. 
• Treatment Complications: During treatment to kill adult worms, fragments of dying parasites can cause blockages in the lungs (pulmonary embolism). This is why strict exercise restriction is vital during recovery.

Our Emergency Services

If your pet is showing signs of respiratory distress, sudden collapse, or severe lethargy, they need immediate medical attention.

We provide Emergency & Urgent Care during our regular business hours to help your furry family member through a crisis.

For most pets in Edmonton, heartworm is something we manage through Wellness & Vaccination Exams and proactive heartworm prevention in Alberta, so it never becomes an emergency.

Why Testing is the First Step

Whether or not you choose year-round prevention, testing is vital. A simple blood test at our hospital detects proteins from adult worms.

We include this in our Wellness & Vaccination Exams because early detection leads to much better outcomes for your furry family member.

Testing confirms your pet is safe to start medication and acts as a safety net if a dose is ever missed. It is especially important for pets adopted from rescues or those with a history of travel.

Frequently Asked Questions

How Does My Pet Get Heartworm if They Never Leave Edmonton?

While rare, local transmission can happen during a warm spell if an infected mosquito bites your pet.

The risk is low, but the disease is severe enough that we prefer to be proactive.

Does My Cat Need Heartworm Prevention, Too?

Yes, cats can also get heartworm disease.

While they aren't the primary host, the disease is often more difficult to diagnose and treat in cats, making prevention even more important.

Why Do I Need a Test Every Year if I Don't Miss Doses?

No medication is 100% effective, and sometimes a pet might spit out a pill when you aren't looking.

Annual testing ensures your pet remains healthy and that the prevention is working exactly as it should.

Are There Side Effects to Heartworm Medication?

Most pets tolerate these treatments very well.

Our experienced veterinarians will review your pet's breed and health history to determine the safest and most effective option for your pet.

When Is the Best Time to Start Prevention in Alberta?

We generally recommend starting in early June.

However, if you plan to travel with your pet earlier in the spring, let's discuss a customized plan for your trip.

Deciding on Heartworm Prevention for Your Pet’s Lifestyle

Choosing heartworm prevention in Alberta is about balancing a low-probability risk against a very high-consequence disease.

Because prevention is safer and more affordable than treatment, it is a smart choice for most Edmonton families.

If your pet travels, protection is a must. If you stay local, we are happy to chat about your pet's lifestyle and help you make an informed decision.

Our veterinary team is here to support you. You can visit our website to learn more about our Parasite Prevention services or to book your next visit.

Have a Question Specific to Your Pet?

While our articles provide great guidance, nothing replaces a one-on-one conversation. We’re here to help.