symptoms of heartworms in dogs

One of the scariest things a pet owner can hear is “your dog has heartworm.”

So it’s understandable when you see pet owners head to the vet for conventional preventatives and treatments …

but is it necessary?

Understanding what the disease is and the common symptoms of heartworm in dogs can save your dog’s life.

What Is Heartworm Disease?

The organism Dirofilaria immitis causes heartworm disease.

It’s a worm that invades the heart and the blood vessels in the lungs.

And dogs get it from mosquito bites.

When a mosquito bites a dog, microscopic worms transfer to the dog’s skin. The tiny worms then enter the dog’s bloodstream through the bite. After floating around in the bloodstream for a couple of months, the worms settle down in the right side of the heart and start growing.

What conventional vets tend to focus on is that these creatures grow to about a foot long and start reproducing. In as little as a year, your dog’s heart can be home to hundreds of heartworms! The resulting inflammation and damage to the heart, arteries and lungs can really do a number on your dog.

What most don’t focus on is that it’s not that easy for your dog to get heartworm.

In order for your dog to get infected:

  • The weather must be warm enough for heartworm larvae to develop in the mosquito (above 14C (57°F)).
  • A female mosquito needs to bite a dog that is already infected with mature heartworms. These mature heartworms need to have produced microfilariae that are alive when the dog is bitten and are at the site of the bite.
  • That same female mosquito then needs to act as an incubator and carry those larvae around for 10 to 14 days until they mature.
  • The female mosquito then needs to bite your dog to transmit the infection.
[Related: What’s the risk in your area? Read this to find out]

Major Symptoms Of Heartworm In Dogs

In most dogs, symptoms usually don’t appear until the worms have reached maturity, about six months from the time of infection.

If your dog begins to exhibit any of the following signs, it’s time to head to the vet right away to test your dog for heartworm:

  1. Coughing or fainting after exercise
  2. Weakness, lethargy or avoidance of physical activity
  3. Stops eating, loses weight or becomes anorexic (too weak to eat)
  4. Difficulty breathing or breathing rapidly (low blood oxygenation)
  5. Chest appears to be bulging (fluid build-up)
  6. Asthma or allergy symptoms
  7. Collapse (blood flow blockage)

Some of the following symptoms may also be signs of heartworm infection:

  • High blood pressure
  • Nosebleeds
  • Lameness
  • Excessive sleeping
  • Blindness
  • Secondary pneumonia
  • Seizures

symptoms of heartworms in dogsIt’s important to remember that, in the early stages of the disease, symptoms of heartworm in dogs are often difficult to recognize. In fact, clinical signs of infection often don’t occur until 6-7 months after the initial infection.

It’s also important to note that adult worms can survive in your dog for as long as 7 years. The longer the worms are there, the more dangerous the conventional treatment becomes.

Preventing Heartworm In Dogs

Treating heartworm disease can be hard on your dog, so it makes sense that prevention is the best medicine.

Your first step is to consider where you live.

  1. Florida and Texas: Due to the year-round warmth and humidity, these states pose a danger of heartworm infection all year long. People living in these areas should use some form of preventative all year.
  2. Southeastern States: These states generally have a heartworm season of about 9 months.
  3. Central States: Most states in the U.S. have a heartworm season lasting 3 to 7 months.
  4. Northern and Mountain States. In northern and mountain states, which are colder and dryer, you may only need a preventative in the heart of summer, June/July, if at all (mosquitoes don’t like high altitude)
  5. Alaska and Hawaii: There’s a moderate risk in these states, with different regions requiring different attention.

With the exceptions of Texas and Florida, there are specific seasons where mosquitos become a problem. In the seasons without mosquitos, it isn’t necessary to use a heartworm preventative.

The next step is deciding what preventative measures to take. Generally, you have two options: conventional or natural.

Let’s compare.

Conventional Prevention

Monthly heartworm preventatives are the gold standard for most dogs …

… but that doesn’t mean you should be rushing to the vet every time you get that postcard reminder in the mail.

Heartworm preventatives are really hard on your dog.

symptoms of heartworm in dogsThe biggest concern with these is how toxic the ingredients are. The drugs are neurotoxins that work by paralyzing the heartworms. Neurotoxins come with disturbing side effects. For instance, the drug ivermectin can cause side effects like ataxia (balance problems), blindness and even death.

And, these so-called heartworm preventive drugs aren’t actually preventives.

They don’t prevent infections. Instead, they kill any heartworm larvae that may already be in your dog’s body. So really they’re treatment drugs, not preventive drugs, meaning if your dog hasn’t been infected, you’re treating him for something he doesn’t even have.

Another problem is that some heartworms are developing resistance to these drugs, meaning they are becoming less effective at preventing the disease.

So what’s the answer? Consider the natural alternatives.

Natural Prevention 

When it comes to preventing heartworm, there are a few things you can do.

  1. Start by boosting your dog’s immune system to help him fight off any infections (not just heartworm).

You can do this by:

  • Switching to a fresh, whole food diet
  • Minimizing vaccines
  • Avoiding prescription drugs
  • Skipping chemical flea and tick products and dewormers
  • Keeping your dog’s environment toxin-free (don’t use chemicals in or around your home or yard)
  1. Keeping the mosquitos away from your dog’s environment is also a good method of prevention.

These tips can help stop an invasion:

  • Eliminate any standing water in your yard. This includes any low spots, ditches and any containers that collect water.
  • Keep your grass short (this is also good for fleas and ticks)
  • Plant mosquito repelling plants like marigold, catnip, rosemary and sage in your garden.
  1. Keep the mosquitos off your dog with a natural mosquito spray.

This is an easy recipe you can try:

What you’ll need:

  • 1 glass spray bottle
  • 25 drops lemon eucalyptus essential oil
  • 2 oz coconut oil or another carrier oil like almond oil

To make it:

  • Mix the ingredients together in your glass spray bottle
  • Shake well before applying
  • Spray your dog all over, taking care not to spray his eyes

symptoms of heartworm in dogs

[Related: There are several other natural options for repelling mosquitoes. Find them here]

But what if it’s too late for prevention?

Testing For Heartworm

The first thing to do if you’re worried about heartworm is have a heartworm DNA test done to see if there is something to be worried about.

Do this before you give your dog any kind of heartworm drugs.

This is a different kind of test that can accurately test for both adult heartworms and larvae. So, if any larvae are present you can treat those before they mature and start causing real health issues. Still, the regular HW test at the vet is a good idea if you have trouble getting the DNA testing done. It will also help diagnose heartworm in your dog. 

One company that offers Heartworm DNA testing is Healthgene in Canada. Your vet will need to contact them to submit your dog’s blood sample for testing. You can find them online here.  Your vet may be familiar with other laboratories that offer this type of test, also known as PCR testing.  Auburn University College of Veterinary Medicine also offers PCR-based heartworm testing. You can find out more here.

So what happens if your dog’s test comes back positive?

Conventional Treatments

Conventional treatments do exist, but they’re toxic and dangerous for your dog.

If you take your dog for conventional treatment, he’ll likely receive treatment with a drug called melarsomine. This drug, which contains arsenic, can kill adult heartworms.

However, it can also damage your dog’s internal organs and the dead heartworms that are released from the heart into the lungs can cause clots and damage to various organs.

With this treatment, vets recommend that dogs stay inside for at least a month. Physical activity should be avoided. An increase in heartrate can pose significant risk.

So what’s the other option?

Natural Heartworm Treatment Alternatives

There are several natural remedies that can help manage the symptoms and eliminate heartworms. These primarily herbal remedies consist of a combination of ingredients, some of which are dangerous for dogs in larger amounts or if taken alone, so it’s best to work with a holistic veterinarian.

A holistic vet can prescribe the right combinations at the right dosages to ensure safe consumption. They can, and do, prescribe other herbal combinations that counteract the negative effects of the heartworm remedy.

To find a holistic vet who uses herbal treatments, search at and select Western Herbs as the Modality.

Here are 3 effective, yet natural, treatment methods:

  1. HWF from Amber Technology

For legal reasons, Amber Technology can’t officially say that HWF treats heartworm, but they do say that it supports the heart by cleaning the cardiovascular system from unwanted foreign substances.

It’s a gentle treatment option made from natural ingredients like black seed, garlic, hawthorn berries and sheep sorrel. It doesn’t work overnight – it usually takes from 16 to 36 weeks to eliminate the heartworms – but your dog doesn’t need to be on a restricted exercise regimen. Keep in mind the risky conventional treatments don’t work overnight either.

For dosing, work with your holistic vet to find the best schedule for your dog. You can also get in touch with Amber Technology if you have questions about HWF.

  1. Homeopathic Remedies

Holistic veterinarian Dr Deva Khalsa has developed a homeopathic heartworm protocol that she has had success with.

It includes the following remedies in all the potencies indicated.

  • Croton tiglium – 9x, 20x, 30x, 200x
  • Lycopersicum esculentum – 9x, 20x, 30x
  • Tanacetum – 9x, 20x, 30x
  • Allium cepa – 9x, 20x, 30x, 200x
  • Allium sativum – 9x ,20x, 30x, 200x

Mix all of these remedies together and give a few drops orally, twice a day for three months.

This combination of carefully selected potencies of the same remedy is called a potency chord. These work on a number of different healing levels in the body at the same time and can be faster acting and more effective than single potencies.

  1. Dr Steve Marsden’s Herbal Heartworm Formula

Steve Marsden DVM published his suggested herbal heartworm protocol in the Manual of Natural Veterinary Medicine and it is used successfully by holistic veterinarians to treat heartworm.

The formula typically includes:

  • Ginger 14 ml
  • Wormwood 9 ml
  • Garlic 4 ml
  • Thyme 14 ml
  • Cinnamon 9 ml

Some vets may add bromelain (dosed separately) to help break down the dead worms.

Again, contact a holistic veterinarian for dosing. The strong tannins in wormwood can cause vomiting and diarrhea so keep it away from dogs who suffer from seizures, kidney or liver disease, or pregnant or lactating dams.

symptoms of heartworm in dogs

There seems to a be a great deal of fear surrounding heartworm. And yes, it can be very tough on your dog if he does get it. The thing is, there are natural ways to prevent and treat the symptoms of heartworm in dogs so you don’t have to put your dog at greater risk.