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How Common Is Heartworm in Dogs?

“And how can I prevent my dog from getting heartworms?”


Most dog owners don’t fully realize how common heartworm is in dogs.

In fact, according to the American Heartworm Society (AHS), heartworm has been found in dogs across all 50 states…yikes! As a responsible pet parent, naturally you want to take preventative steps to ensure your dog is safe from this serious and potentially life-threatening disease.

Luckily, that’s where the veterinarians at Westmonte Animal Clinic come in! In this blog post, we’ll cover everything you need to know about preventing heartworm in dogs.


What Causes Heartworm Disease?

To begin let’s start by defining what exactly heartworm is.

Also known as “dirofilariasis,” heartworm is a disease caused by…yes, you guessed it…a worm. Scientifically, these worms are called “Dirofilaria immitis.”

Dogs get heartworms from mosquitos. When an infected mosquito bites a dog, the bloodborne parasite is transferred to the dog as microscopic larvae. Before long, they grow to be 5-12 inch-long adult worms that wiggle their way into your pup’s blood vessels in their heart and lungs.

Heartworms can live up to five years using a canine’s body as a host. They can also multiply into the hundreds.

Gross, right?



Where is Heartworm Disease Found in the World?

So, how common is heartworm in dogs really?

Unfortunately, nowhere in the United States is entirely heartworm-free. Data published in 2019 found that there are approximately 1.1 million infected dogs in the United States. However, this is almost certainly an undercount, as many cases go unreported and untreated by veterinarians.

Fellow Florida pet owners should be especially cautious since mosquitos thrive in our hot, humid climate and swampy areas. Over 16 species of mosquitoes call Florida home.

But the truth is heartworm in dogs is a global problem.

Anywhere mosquitos are present, heartworm is a health risk!


5 Symptoms of Heartworm in Dogs

Now that we understand how worryingly common heartworm in dogs is, the next smart thing to do is learn about the symptoms. By educating ourselves regarding what red flags to watch out for, we can be proactive in keeping our dogs safe.

Here are 5 signs a dog may have heartworm disease.

1. Dry and Persistent Cough

Remember, heartworms settle in around the heart and lungs. Once these horrid parasites begin reproducing in the blood vessels, a dog will often get a soft and dry cough that never seems to go away.

2. Lethargy

Secondly, a dog diagnosed with heartworms will act lazier than normal. A dog who suddenly refuses to go on walks, doesn’t want to play, and has low energy levels could be suffering from heartworms.

3. Loss of Appetite

Another red flag is weight loss. An advanced heartworm infestation attacks the heart, lungs, liver, and kidneys. This can make a dog feel ill and turn their nose up at food.

4. Swollen Belly

A swollen belly is another indication that your dog might be suffering from heartworm. Because the dog’s heart is struggling to pump blood fast enough, fluid builds in their abdomen.

5. Trouble Breathing

Lastly, pay attention to breathing. If your dog has difficulty breathing, always treat this as an emergency. Shallow and rapid breaths (in addition is dry coughing) could be a sign of respiratory problems caused by heartworms disrupting the flow of oxygen in a dog’s lungs and body.

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Easy Ways to Protect Your Dog From Heartworms

As you can see, heartworm in dogs is a serious issue!

It can lead to heart failure, organ damage, lung disease, and, sadly, even death.

To protect your four-legged best friend, you can:

  • Talk to a veterinarian about heartworm prevention medication
  • Monitor their behavior/body for signs of heartworms
  • Undergo regular testing



Although heartworm disease is found all over the world and throughout the United States, the US Food and Drug Administration shares that it “is most common along the Atlantic and Gulf coasts from the Gulf of Mexico to New Jersey and along the Mississippi River and its major tributaries.”

Therefore, for anyone wondering, “How common is heartworm in dogs?” the answer is…common enough to talk to your veterinarian about protecting your dog!

Heartworm should be treated like the dangerous disease it is. Here at Westmonte Animal Clinic, we believe the best treatment is prevention. Regular pet wellness exams help us stay on top of your pet’s health, identifying changes as they occur and hopefully catching diseases or other health issues in their early stages.

If there are any red flags or causes for concern, our in-house diagnostics will check for heartworm disease, tick-borne illnesses, and more

Give us a call at 407-862-6892 to let our friendly staff help schedule an appointment for you today.