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Why Do Dogs Need Heartworm Medicine: Causes, Symptoms, and Prevention

June 6, 2022
dog playing with toy outside

Most dog owners know about heartworm. You know the name of the disease and that it’s critical to prevent it for your dog’s good health. But generally, most people don’t know much about what it actually is and why heartworm meds for dogs is so important for prevention. Your first thought may simply be wondering “how do dogs get heartworms?” especially when your furry friend spends most of its time in clean and “safe” spaces – your home, the backyard, your neighborhood, and well-known community areas.


It may help to learn more about heartworm disease. In this article we’ll discuss what causes heartworm in dogs, how to prevent dog heartworm, heartworm meds for dogs, the signs to watch for, and treatment. 

What Causes Heartworms in Dogs

If you’re asking yourself, “do dogs need heartworm medication at all?” then learning what causes heartworms in dogs and its effects may give you a better understanding for why preventative heartworm meds for dogs is so critical in the first place. When most of our beloved pups are constantly in protected and controlled spaces, how can dogs get heartworm when you don’t let them run amuck? 


In a nutshell: mosquito bites. Heartworm disease is the result of getting infected with the parasite known as roundworm (Dirofilaria immitis). It spreads only through the bite of a mosquito that is already infected with the parasite. The mosquito ends up with the parasite only by biting another animal that’s been infected. After a dog has been bitten, heartworm larvae will travel throughout their body, mature, and reproduce. After six to seven months, heartworms will be fully mature with a spaghetti-like appearance, ranging in length from 4 to 12 inches long. At this point, heartworms can cause severe and sometimes permanent damage to the heart, lungs, and other organs. In extreme cases, heartworm disease can end your dog’s life. 

How to Prevent Dog Heartworms

We cannot stress enough how critical prevention is for the health and safety of your dog. Treatment for heartworm disease (read more below) is long and stressful on your dog, not to mention emotionally stressful for both dogs and dog owners and can get costly. 


Since it’s impossible to avoid mosquitos altogether, prevention is best handled with specific heartworm medication prescribed by your vet. There are many FDA-approved heartworm meds for dogs on the market today and all require a prescription from your local veterinarian.


  • What form do heartworm medications come in? They can be a topical liquid or an oral tablet. Varying products will offer heartworm prevention only and some add protection against other parasites. It’s best to discuss with your vet which medication is right for your dog.
  • How often should I give my dog heartworm medicine? Heartworm prevention products are primarily administered monthly. 
  • Do senior dogs need heartworm medication? Yes! Heartworm is not biased to the age of your dog. Dogs of any age are a natural host for heartworms. 


Chipman Road Animal Clinic can offer more information regarding differing heartworm prevention products and how to prevent dog heartworms. If you have any questions, give them a call at 816-524-1886.

mosquitos on dog outside

What Are the Signs of Heartworm Disease?

Unfortunately, there are very few symptoms to reveal heartworm disease in its earliest development. Visible warning signs often do not show up for several months. The degree of disease severity in your dog will correspond with what’s known as “worm burden” – the number of worms inside their body. The higher the number, the more severe the symptoms.


The earliest signs are occasional and mild coughing and getting more fatigued than normal after regular physical activity. If your dog is naturally more active, excess fatigue will be more apparent. Their breathing may become more labored or abnormal. More severe symptoms can be any of the following:


  • Bloating
  • Sickly Looking 
  • Fainting
  • Ongoing Dry Cough
  • Loss of appetite
  • Unusual Weight Loss
  • Distended Chest
  • Dark or Bloody Urine
  • Gums Appear Pale

Treatment: Talk to Your Vet Right Away

Prevention is the best form of treatment, but, if you find your pup in the unfortunate condition of possibly having heartworms, contact your vet immediately! Starting treatment as soon as possible will reduce the amount of damage the heartworms can inflict in your dog’s body. 


Treatment can only be administered by your veterinarian. They’ll first run a test to confirm heartworm disease. If it’s positive, your vet will administer multiple injections on separate visits to treat the disease. The treatment is effective and will kill the worms quickly. If you’re dog ends up with heartworm, this is the only treatment available to eliminate the worms. Hopefully, knowing this now will impress upon dog owners just how important and much more cost-effective heartworm prevention treatment vs. treating the disease itself.

For the Best Heartworm Prevention Advice, Give Chipman Road Animal Clinic a Call!

If you have more questions about why do dogs need heartworm meds or if you think your dog may have contracted heartworm disease, contact Chipman Road Animal Clinic at 816-524-1886 and we’ll be happy to guide you and answer all your questions. Your pups deserve the best and Chipman Road Animal Clinic is passionate about pets and giving them the best!

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