Dog with Heartworms

Top 9 Heartworm Questions to Ask Your Vet

In News by Pharr Rd. Animal Hospital4 Comments

Heartworms and other parasites are always heavy on pet owners’ minds each spring.

At Pharr Road Animal Hospital, our veterinarians get a lot of questions from people who want to keep their animals safe and healthy.

To help educate pet owners, here are the top 9 questions we get about heartworms—some of the answers may surprise you!

  • How do animals get heartworms?

Short answer: from the bite of a mosquito.

Mosquitoes can pick up heartworm larvae when they bite an infected animal.  Those larvae develop in the mosquito for a couple of weeks before being passed back into other animals in an ‘infective’ form.

  • Can my cat get heartworms?

Yes, it can.

Though dogs are considered the ‘natural host’, heartworms can be found in a variety of different mammals, including foxes, wolves, sea lions, and even humans.

Adult heartworms are rare in cats, though they don’t have to be mature to do irreparable damage.

  • How can I tell if my pet has heartworms?

Actually, you probably can’t yourself.

If your pet’s infection is far along, some of the symptoms may offer a hint.  But heartworm detection requires a blood sample.

Even then, it takes 6 months for a dog to test positive.  For cats, testing still isn’t reliable, largely because it is so rare.

  • What are the symptoms of heartworms?

Heartworms infect the heart, lung, blood vessels, and other body tissues.

However, it can take 2 to 4 years for a dog to show symptoms.  At first, these may include reluctance to exercise, a mild persistent cough, or decreased appetite.  These correspond to an enlarged heart and damaged lungs.

As things progress further, you may notice a bloated belly.  And if you let heartworms grow in your dog unchecked, you can expect heart failure.

For cat’s, things are a bit trickier.  

Heartworms may lead to a range of issues such as coughing, vomiting, weight loss, bloated bellies, even difficulty walking.  However, very often, the first symptom is sudden collapse or death.

  • How can I prevent my pet from getting heartworms?

There are basically two things you can do:

Test for heartworms regularly and give your pet a heartworm preventative medication year round.  These require a prescription or application by a licensed vet and are really the only sure way to keep your pets heartworm-free.

Otherwise, you could find a completely mosquito free location.

  • Are heartworms contagious?

Not directly.  Heartworm transmission requires two ingredients: an infected animal and a host mosquito.  Without both, your pet can’t pick up a heartworm infection.

  • Can my pet get heartworms inside?

Yes.  Mosquitoes can travel inside.

  • Are heartworms limited to any geographical location?

No.  Heartworms can live anywhere both potential hosts and mosquitoes survive.

Cases of heartworms have been reported in all 50 states and many foreign countries.  In the United States, it is most common along the Gulf Coast.

  • Can I treat my pet for heartworms in my home?


Heartworm treatment is pretty intense.  Currently, there are no approved treatments for cats.  

For dogs, you’re looking at a series of injections that require hospitalization and restricted activity for 6 months or more.  As you’d expect, success rates are higher when infections are caught in the earlier stages.

If you want your dog or cat to get checked just give us a call or fill out our contact form.


  1. I live in a place that has a lot of mosquitoes and so I definitely do not want my dogs or cats getting heartworms. It would definitely be useful if I could tell whether or not my pets had them, though. I want to have them checked for the condition regularly, but I why exactly does it take six months for them to test positively?

  2. Thanks for sharing. I had no idea that my dog could get heartworms inside. Darn mosquitoes are real pests. I need to take my dog in and get her a check up. It would be nice to make sure she has a clean bill of health.

  3. Eugh, I hate talking about worms, but I really appreciate the explanations you give about heartworms. My bio teacher spent two weeks of lecture on a discussion of worms, and I have never quite recovered. Still, everyone needs to have a worm talk at some point so that they understand how to recognize symptoms and avoid possible infection. Is infection even the right word? For our own health, as well as our pets, we need to know these things.

  4. I did not know that it was so important to make sure that you have heart worm medicine that is up to date. The fact that there are so mane diseases that are transmitted by mosquitoes to dogs. I will make sure that I update the heart worm medicine and make sure that my dog stays healthy.

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