Lola had Heartworm Disease… here in Unionville!

By September 20, 2018 January 2nd, 2019 Uncategorized

Heartworm is a serious disease that infects the heart of dogs. It is transmitted by mosquitoes! We and many of our dog owners have done a great job fighting this infection over the past 30 years. But every now and then, a dog comes in that carries the parasite. This should not happen!

This year, we saw a super friendly and calm Golden Retriever girl called Lola. She is a most wonderful dog, but she had heartworm disease.

Heartworm disease is one issue we’ve seen that all veterinarians in Markham wish didn’t exist. It causes stress and pain for everyone involved. If left untreated, it usually causes early death. Treatment is possible, but not without risk. And it is costly.

We need to spread awareness about heartworm disease existing here in Markham as much as possible. Though it doesn’t happen that often for us (we haven’t seen a dog infected with heartworm for several years), when it does, it really hits home.

 Imagine a 14 inch worm living in your heart

Let’s start with what this disease is and what it involves.

A heartworm (Dirofilaria immitis) is a large worm that can grow up to 14 inches long. As the name implies, it makes its home in the hearts of canines and similar species like foxes, wolves, coyotes, and cats. In very rare cases, humans have been infected.


How does a dog end up with heartworm disease?

Mosquitoes transmit the disease. Mosquitoes? That’s right. Their bites can place nasty larval heartworms (the microfilariae) on your unsuspecting dog’s body.

“But how is that possible?” you ask. “What do mosquitoes have to do with worms?”

Let’s put it this way: mosquitoes get the heartworms from infected dogs, coyotes, foxes, your neighbor’s dog, etc. and transfer them to vulnerable ones. The worms aren’t injected directly into the bloodstream like you might think. Actually, the larva is placed next to the bite in a tiny drop of mosquito spit.


What could happen if a heartworm problem isn’t dealt with quickly, if at all?

Many pet owners don’t realize what’s happening to their dog, and the results can be devastating.


For instance:

Fido’s heart has to work harder than normal. This is because heartworms keep blood from flowing the way it should.

Blood clots could form, and that means possible heart failure.

What are the signs of heartworm disease?

We don’t want to scare you, but it’s not always obvious. If Fido has only a few worms in his system, chances are you won’t notice anything for several years. He’ll be his goofy, energetic self. When the disease gets worse, then you could see:

Weight loss

Lack of energy


Loss of appetite

Swollen belly/pot belly

Difficulty breathing



Some of these can be signs of other diseases, but talk to your veterinarian in Markham no matter what.

Once you know what you’re dealing with, your helpful vet clinic staff can tell you how advanced the disease is (usually through chest x-rays and further tests). Is it in the second stage? The fourth? The answer will be clear. Is it treatable?


What should or shouldn’t I do to keep my pet from getting heartworms?

Prevention is easy. All it takes is giving a medciation (there are some that get applied on the skin, others are like cookies) once per month in the warm season of the year here in Ontario. If you are traveling south in the winter you vet in Markham will recommend that you give the mediation all year round. Heartworm disease is more common in Florida etc.


Lola did not get this preventive medication. This is so sad. Her story should be an inspiration for everyone to give their dog the monthly prevention medication.


What do you do if your dog has the disease?

In mild or moderate cases of heartworm disease, patients usually start out with an oral antibiotic before adulticide injections begin. This helps weaken the worms and ups the chances of success.

Worms typically die off completely within a few weeks. It’s a slow process, so you have to be careful. If too many worms die off too fast, the arteries get clogged with worm carcasses.


Please see next month’s blog at to find out how Lola is doing.


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Dr. Ernst Marsig, veterinarian in Markham

Fear Free Certified Practitioner

Practicing Veterinary Medicine in Markham for a Long and Happy Life of ALL Your Pets.

Animal Hospital of Unionville, a veterinary clinic on the north side of  Hwy 7, serving all pets in Markham, Richmond Hill, Scarborough, Stouffville, and North York since 1966. We are your family vets for dogs, cats, pocket pets (rabbits, chinchillas, gerbils, mice, rats, hamsters, guinea pigs, skinny pigs, etc.), ferrets, and birds (budgies, cockatiel, parrots, amazon, cockatoo, love birds, conures, African greys, finches, canaries, etc.). We pride ourselves to provide cost effective veterinary medicine and give you options for treatments. Some may think our services as cheap, but our goal is to give good value.

Disclaimer: No part of this website constitutes medical advice. Readers are advised to consult with their veterinarian.

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