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Protecting Pets from Heartworm Disease


Heartworm disease is nearly 100 percent preventable.  Still, according to the American Heartworm Society (AHS), most pet owners don’t use preventatives.

Actually, if you want to get technical about all this, in dogs – preventatives don’t completely prevent heartworm – not completely.

According to Dr. Stephen Jones, immediate past president of the AHS in a story he authored in Today’s Veterinary Practice: 

  • If a dog has heartworms, it has heartworm disease.
  • Disease pathology continues to progress until all heartworms are eliminated.
  • If a dog had heartworms earlier in life, some permanent disease remains.

Heartworm 101

Heartworm disease is spread my infected mosquitoes. There are lots of mosquito species (who knew), and many carry heartworm And while heartworm is far more common in the south – where more mosquitoes are seemingly omnipresent, if you live in Minnesota or Wisconsin, for example, you know how many mosquitoes are soon about to buzz about after early Spring rains. In fact, heartworm occurs in all 50 states.

Traditional heartworm protection is necessary for dogs – as well as cats and ferrets – according tot he AHS.

Here’s how that works: An infected mosquito bites an uprotected dog, and little “baby heartworm,” called mircofilaria, infect the dog. The heartworm preventatives do whack nearly 100 percent of the microfilaria. And by killing them, it prevents the growth of heartworm.  So, those worms never do get the chance to grow a foot long and live in your pet’s heart and lungs. Imagine dozens of or more of these spaghetti-like worms living inside your dogs heart and lungs. No surprise, this can be deadly – or at the very least impacts quality of life.

However, what we know today is that even these little microfilaria cause permanent damage. So, better still – a dog is not bitten at all.

No Mosquito Bites Is the Best Fight

Vectra 3D is a very cool idea, not only does Vectra 3D (a spot-on product available through veterinarians) work as a force field repellent (preventing a mosquito from biting in the first place), but also the product stops fleas and ticks.

Since dog owners must get a flea/tick product anyway, seems to make sense. Note: AHS still recommends a traditional heartworm product.

Another good reason for the double-protection or multi-modal approach is that some heartworm have now built in resistance to traditional products.

At least heartworm in dogs can be treated. The treatment is arduous and expensive – but it usually works.

Heartworm and Cats

Here’s why you don’t want a cat to get heartworm: It’s because there is no treatment. Too few talk about cats and heartworm, but it’s a real threat, even for indoor cats. Have you ever seen a mosquito in your home? Of course. And mosquitoes aren’t discriminating about how they bite. Heartworm is actually the second leading cause of sudden death in cats and can also cause heartworm associated respiratory disease, which impacts the quality of life for cats. As in dos, the best treatment is prevention.

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Steve Dale is a certified animal behavior specialist who has been a trusted voice in the world of pet health for over 20 years. You have likely heard him on the radio, read him in print and online, and seen him speaking at events all over the world. His contributions to advancing pet wellness have earned him many an award and recognition around the globe.

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