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The Truth About Heartworms

You may have noticed that each time you visit our hospital, we ask you if your pet is in need of a refill of its heartworm preventative. We wanted to take a little time to shed some light on why asking this question is one of our top priorities.

What is heartworm? Are there actual worms involved? Yes, heartworm is caused by actual worms! These parasitic worms can reside in the heart, lungs, and vascular system of dogs, cats, and ferrets, and may grow to be up to a foot in length.

What are the signs and symptoms of heartworm?

Since heartworms cause severe damage to the heart, lungs, and vascular system, common symptoms include coughing, exercise intolerance, lowered appetite, and weight loss. As the disease progresses, some pets may go into heart failure, resulting in collapse and even death. The more advanced heartworm disease becomes, the less likely it is that a pet will recover fully after treatment.

How is it spread?

Believe it or not, heartworm is spread by the bite of a mosquito! When a dog is harboring adult heartworms, microscopic baby worms called “microfilaria” are produced and float around the blood stream. So, when a mosquito bites an infected dog it picks up some of those tiny baby worms, which grow and mature into infective larvae inside of the mosquito. Once the mosquito is infected, the larvae can enter into a dog or cat through the mosquito’s bite.

So, how can we prevent it?

The most important thing we can do is give our pets a monthly heartworm preventative containing ivermectin every 30 days year round. At our clinic, we carry and recommend Heartgard, a beef flavored chewable that can be given just like a treat, though it can only be given to dogs. We also carry Revolution, which is administered topically to the skin between the shoulder blades and is great for dogs that may have food allergies or sensitive stomachs; Revolution also makes a topical preventative that can be administered to cats. Additionally, testing your pet yearly for heartworm is also important, since heartworm is such a progressive disease and there are few early signs. Prevention is especially important for our feline friends as there is no safe treatment for heartworm disease in cats.

Here is a link to a story from the ASPCA on heartworm disease : We hope this answered some of the questions you may have had about heartworm disease and prevention, but as always, don’t hesitate to call and speak with our staff if you have any further questions or concerns!

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