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  • Writer's pictureNAH Admin-Coordinator

What Are Heartworms, Actually?

You hear it every time you bring your pet for any visit: “What heartworm prevention is your pet on?”

You know that question is a very important one, since heartworm disease can be deadly for your pet. But do you know why it is so dangerous? In honor of Heartworm Awareness Month this April, we are here to break down all the details of heartworm disease and why you need to keep your pet on their prevention for it.

Heartworms are large parasites that live within the heart and lungs of affected pets. Once these parasites start to multiply in the pet’s system, symptoms such as a cough, decreased appetite, weight loss, and fatigue after minimal activity can develop. These symptoms are more prevalent in dogs than cats, but are still dangerous for both as they can lead to lung disease, heart failure, and other organ damage if left untreated. In some cases, pets can even go into cardiovascular collapse due to an extreme number of worms blocking blood flow to the heart.

So now that we know how dangerous heartworms can be, how are they actually transmitted?

Lifespan of a Heartworm courtesy of the American Heartworm Society

The answer: mosquito bites. To put it into perspective, offspring of a heartworm parasite are microscopic. Once these baby worms are born, they are implanted into the bloodstream of the affected pet. This makes them easily transmittable by way of mosquitos biting the affected animal and subsequently spreading the microscopic offspring to all the animals it bites afterwards. Once transmitted to a healthy pet, those larvae take 6 months to mature into adult heartworms. Each adult heartworm can then live in the pet’s body for up to 5-7 years in dogs and 2-3 years in cats according to the American Heartworm Society.

Both the longevity of these parasites and the ease of transmission for their offspring are why keeping your pet on prevention for them is so important. Yearly testing as well as monthly preventatives such as Sentinel Spectrum and Simparica Trio will ensure that your pet never experiences this disease.

If your pet needs a heartworm test and/or heartworm prevention, give any of our locations a call to get an appointment scheduled! In fact, you even have a chance to win a Mini Pet Photo Session with Tanya Consaul Photography when you refill 6 months or more of your pet’s heartworm prevention with us! For more information on this raffle, please visit

For more information on heartworm disease and the threat it poses to your pet, visit


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