Avoiding the Heartbreak of Heartworm


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Summer is just around the corner, and for many of us that means an end to cold weather and the beginning of barbecues, fun in the sun, swimming, camping, food trucks galore… and mosquitos. There’s just no getting away from the little pests. So, with that in mind, I thought it was about time for a few words about heartworm and how it can affect your dog.

What Is Heartworm?

Heartworm is a type of roundworm that can invade your dog’s heart and lungs. It is transmitted via mosquito from infected dogs to other dogs. Just one mosquito can bite countless dogs, and heartworm can be a problem anywhere that it ever gets warm enough and damp enough for mosquitos to flourish. In fact, there have been cases of heartworm in every US state, and every Canadian province.

At first, the heartworm parasite is present as microscopic filaments that mosquitos can transmit in their saliva. When a dog is bitten, these tiny organisms begin to develop into larvae. Then, anywhere from six to seven months later, the larvae grow into worms, and the worms begin to grow and reproduce. An adult worm can grow up to a foot long, and can live up to seven years.

Symptoms of Heartworm Infestation

In the early stages, there are no symptoms. By the time the larvae develop into worms, the dog will become listless, tire easily, lose weight and have difficulty breathing. With severe infestations, the veterinarian will observe abnormal sounds in the lungs due to fluid retention. The dog may pass out because of reduced blood flow to the brain.

As if this doesn’t sound bad enough, usually symptoms are not noticed until the disease has progressed to the point where treatment will be difficult, if not impossible. Even with regular testing for heartworm, it is hardly ever detected before the damage has become irreversible.

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Treating Heartworm

Treatment is complicated, expensive, and often ineffective. As is the case with most canine diseases, prevention is far better than a cure. There are inexpensive medications from your veterinarian that can be given even to puppies as young as six weeks.

When treatment is needed, it usually includes bloodwork, x-rays and other tests that can determine the seriousness of the infection. Then the dog can be given injections that will kill the heartworms. In years gone by, pure arsenic was used, and the side effects could be very problematic. Today’s medicines still contain arsenic, but have fewer side effects.

Following the injections, there will be a lengthy recovery period during which the dog must be kept quiet for several months. This is because as the worms begin to die, they break up and can block the pulmonary vessels. This is actually when the dog is at the greatest risk of dying post-treatment. Exercise increases the risk of pulmonary blockage, and in fact, most dogs that die following treatment die because their owners have allowed them to play.

Preventing Heartworm

The medication needed to prevent heartworm is available from your vet, and usually costs between $35 and $80 annually, depending on the size of your dog. Medications are available as pills, ointments or injections, and they work to prevent the worms from developing if the dog should become infected.

You should talk with your vet about the heartworm medications that will be most appropriate for your dog. Ivermectin is commonly used, and is very effective, but can be poisonous to some dogs. For example, Australian Shepherds, Shetland Sheepdogs, Smooth Collies and Rough Collies are prone to a genetic mutation, and if that mutation is present, ivermectin can actually be poisonous. Your vet will usually be able to recommend an alternative medication if ivermectin sensitivity could be a concern.

If, for any reason, your dog cannot tolerate heartworm medication of any kind (although this is rare), then you will have to take measures to keep mosquitos away. Remember that mosquitos love standing water, so make sure that you remove potential sources wherever possible. If your yard has a swampy area, have it filled in, and also avoid walking your dog in wet areas. Make sure to change outdoor water bowls frequently. Fit your doors and windows with screens, and perhaps put up a bug light or two. And of course, keep your dog inside during the early mornings and evenings, since this is when mosquitos most often come out to wreak havoc. Simply stated, the less frequently your dog is exposed to mosquitos, the less likely he is to be bitten.

The use of an insect repellent is also advised, but you should avoid using human bug spray on your dog, since many preparations containing DEET can be irritating to the skin, and can also make your dog sick if he licks the repellent. There are preparations made especially for dogs, like All Terrain Natural Pet Herbal Armor. It ordinarily retails for $9.49, but is available in a 4-oz. spray bottle at Amazon for $8.33. It contains no DEET, and is non-irritating and allergy tested. It also resists sweat and water, and provides 100% protection for 2 hours, and close to 96% for 3 hours.

Related Content:

The 411 on Heartworm Prevention for Dogs
Persistent Pupillary Membrane in Dogs
What Does It Mean When Your Dog Can’t Stop Coughing?(Video)

The Final Word

From where I sit, you can’t put a price on love – certainly not the kind of love you get from your dog. So for the sake of $80 per year, tops, make sure your dog is protected from heartworm. For that matter, consult your vet about any other preventative treatments or immunizations that your dog might need in order to stay healthy, and make the time to have them done. I could tell you horror stories about dog owners in tears because they put off immunizing, and then either had to watch their beloved pet be put to sleep because it was too late, or because the cost of treatment was going to be so high they had no hope of ever affording it.

You don’t want to have your heart broken, so look after your dog’s heart.