A Pet Owners Guide to Heartworm Prevention, Symptoms, Causes, and More


Heartworm is a very serious pet disease. It can cause various symptoms. If left untreated, it can take your pet’s life.

It’s prevalent in southern states and expanding in other hot spots across the country. The good news is that there are ways to prevent this deadly disease.

As a loving pet owner, you should know everything there is to know about heartworm prevention. Consider this to be your ultimate guide to heartworm prevention. Read on to learn more about it.

Heartworm Symptoms

The symptoms of heartworm vary across the stages of the disease. The severity of the symptoms increases with the onset of each stage.

One of the early-stage symptoms of this disease is a persistent cough. This isn’t like a regular cough that’s sporadic. The cough from heartworm disease is dry and prolonged.

This cough can cause your pet to cough even during regular physical activity. This is due to the heartworm parasites trying to move into the lungs. As the parasites try to make their way in, they cause discomfort and make it hard for your pet to breathe.

Do you notice your pet lacks energy? If your loved one doesn’t want to go out for a walk, it might be a sign of heartworm. The lethargy can even make walking a strenuous activity.

Another early-stage symptom is weight loss. Without adequate energy, your pet may not eat. This will result in rapid weight loss.

Middle-stage symptoms can arise as the heartworms mature. The onset of this stage occurs when the parasites make their way into the lungs and veins.

In this stage, heartworms can affect a pet’s breathing. Fluid can build around the blood vessels in the lungs. This can make it hard for the lungs to get oxygen into the bloodstream.

As fluid continues to fill up the lungs, you might start to see your pet’s chest protrude. You may even observe the ribs have a bulging appearance.

Late-stage symptoms include an enlarged liver and heart murmur. A dog’s lung can have abnormal sounds in this stage.

It should be noted that cats might present with different symptoms. Heartworm symptoms in cats can be subtle.

Cats may experience periodic vomiting and even faint. Seizures are also common.

Heartworm Causes

The cause of heartworm disease is a parasitic worm called Dirofilariaimmitis. Mosquitoes can spread this worm through their bite.

The mosquito acts as an intermediate host. As this type of host, the mosquito lets worms live inside of it. During the time the worms live in the mosquito, they gain the ability to become infective.

A pet serves as the definitive host. Once the worm is in the animal, it’ll mature into an adult. As it grows, the worm will mate and produce offspring.

The heartworm will live in the definitive host’s heart and lungs. The heartworm will also live in the host’s blood vessels.

Heartworm disease isn’t contagious. A dog that has heartworm can’t pass it along to another dog even if there’s close contact between the two.

A heartworm’s lifespan when it’s in a dog is between 5 to 7 years. Heartworms look like strands of cooked spaghetti once they reach maturity. Males are smaller in size compared to females.

The number of worms living in a dog is known as worm burden. An average of 15 worms can live in a worm burden. As many as 250 worms can live in one.


If you suspect your pet has heartworms, you should take your pet to the vet for testing. It’s critical for your pet’s recovery to detect this disease early.

Testing for heartworm disease in dogs requires doing a simple blood test. The vet may order one of two tests. There’s one that detects adult worms and one that detects microfilariae, or baby worms.

Testing for cats differs and tends to be harder to do. A vet can order a variety of tests. They can include blood tests, X-rays, and an ultrasound of the heart.


If the test is positive for heartworm disease, your pet will need to receive treatment right away. Treatment differs for cats and dogs.

Treatment for dogs involves restricting their exercise. Too much exercise can increase the rate at which heartworms harm your dog’s health. It can lead to heart and lung damage.

Your dog’s vet will administer the heartworm medication. Medications used to treat this disease are effective. The vet will order more tests to confirm that all the heartworms have been eliminated.

Treatment for cats is limited. No drugs are approved for heartworm infection in cats. A vet may prescribe drugs to control inflammation.

Surgery is an option for cats that have a serious infection. Surgery is performed on the cat’s heart to remove adult worms.

The vet will seek to stabilize your cat. If the infection worsens, the vet might recommend hospitalization. In the hospital, the cat may receive IV fluids and antibiotics.

Don’t put off treatment. Failure to treat this disease can increase the risk of complications like heart failure. It can also increase the risk of organ damage.

Heartworm Prevention in Dogs

When it comes to heartworm disease, the best treatment is prevention. Every dog owner must consider heartworm prevention measures.

Dog owners should give their pooch year-round preventative medication. Preventative medications come in oral or topical form.  Talk with your dog’s vet to determine which medication is best for your dog.

Schedule an annual checkup for your dog. Routine vet visits can help detect not only heartworms, but other health issues as well. The vet will test for heartworms.

Dogs should undergo heartworm testing every 12 months. Even dogs on preventative medication should undergo heartworm testing.

One of the best things you can do to protect your pup from this disease is to keep your home and yard free of mosquitoes. These pests are a threat to your dog’s health.

Mosquitoes breed in standing water. Even a small amount of water can be enough for mosquitoes to breed.

Don’t leave empty containers with water. Dump them out. Do the same with old flowerpots that contain water.

You can use insecticide spray for your yard. This type of spray contains chemicals that can kill mosquitoes. If you prefer, you can use natural ingredients to repel mosquitoes.

This is a routine you’ll have to keep up with every year. It’s the best way to prevent heartworm in dogs.

Heartworm Prevention in Cats

Prevention for cats consists of monthly heartworm preventive medications. Vets recommend all cat owners give their cats these preventive medications.

It’s a good idea to talk to your vet and go over all the different options. Your vet will consider if your cat is an indoor or outdoor cat. Your vet will also consider how often you’ll want to give your cat the medication.

Preventative medications come in different forms. There are chewable tablets and topical solutions. Most of these drugs can also prevent other issues like flea infections and ear mites.

There are two ways you can get access to these medications. You can buy them directly from your vet or get a prescription so you can get them from a pharmacy.

Keep in mind that there are no natural heartworm preventatives. Don’t buy any herbal solutions or essential oils that claim to prevent heartworms in cats. These can be dangerous as they may pose a threat to your cat’s health.

Consider Purchasing a Wellness Plan for Your Pet

Heartworms don’t discriminate against breed. All types of cat and dog breeds are susceptible. These critters can wreak havoc on a pet’s health.

The costs of heartworm medication can add up. To help offset the costs of the medications, you should consider investing in a pet wellness plan.

This type of plan can cover preventive pet care services. Heartworm prevention is included in a pet wellness plan.

If you love your pet, you should invest in one. Your pet is part of your family. Find more information here to determine which plan is best for your pet.

Use This Guide to Prevent Heartworm Disease in Your Pet

Heartworm disease can prove to be fatal to pets. At the first signs of this disease, you’ll need to take action. Take your pet to the vet to get tested.

Treatment can help eliminate heartworms. You shouldn’t wait for your pet to get infected with heartworms. The best policy is to be proactive.

Heartworm prevention is the key to protecting your pet. Use this guide to help you protect your pet from this terrible disease.

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