What are Heartworms and how does my pet get infected?
Heartworms are parasites that invade a pet’s circulatory system and heart. The adult heartworms produce offspring called microfilariae which circulate in the infected pet’s blood. Mosquitoes feed on an infected pet, serve as a host while the microfilariae mature for approximately two weeks, then transfer infective heartworm larvae when they bite healthy pets.

These heartworm larvae migrate through the pet’s tissues and circulatory system and reach the heart in five to six months, where they arrive as small worms about two inches in length. Once they are in the heart, the adult worms reproduce and grow. They may reach twelve inches or more in length and may stay in the pet’s heart for several years. In a severe infestation, a dog’s heart may contain up to 300 worms.

What type of pet is most susceptible to heartworms?
Breed, sex, and age do not affect your pet’s susceptibility to heartworms. Dogs get heartworms much more commonly than cats, although the incidence of heartworms in cats is higher than once thought. Pets that spend time outdoors come into contact with mosquitoes more frequently than indoor pets and are at increased risk for heartworms. The disease is found in virtually all parts of the United States and Canada.

How can I help prevent Heartworm Disease?
Highly effective preventive medications are available for dogs and cats that are not infected and for pets that have been treated successfully for heartworms in the past. Our veterinarian will test your pet for the presence of heartworm before prescribing medication.any case, early detection and ongoing prevention guards against needless suffering.

If you live in a known heartworm area, or if your pet is traveling with you to a known heartworm area, our veterinarian may prescribe preventive medication. If your pet becomes infected, these medications will prevent heartworm larvae from developing into adult heartworms. It is crucial to administer all prescribed medications as directed.

As a safeguard, our veterinarian may recommend annual or biannual screening tests – even for pets that are on heartworm preventive medicine.

What physical signs might my pet show when infected with heartworms?
There are several signs that might indicate the presence of heartworms in your pet. Talk to our veterinarian right away if your pet:

• Has sudden weight loss
• Develops a rough hair coat
• Has difficulty breathing
• Develops a soft, persistent cough
• Tires easily
• Is listless or weak

Many of these symptoms are most noticeable after exercise. Heartworms clog the heart and/or the main blood vessels, reducing the blood supply to other organs such as the lungs and liver. Major bodily functions, including breathing, are affected.

How is Heartworm Disease treated? Our veterinarian will require a blood sample to confirm the presence of heartworms. Once this has been done, further tests may be required to determine whether or not your pet can tolerate heartworm treatment. These tests include, but are not limited to: blood chemistry panels, radiographs (x-rays), and electrocardiograms.

If your dog’s heartworm infection is not too severe, our veterinarian will administer an injectable drug to kill the adult heartworms. Complete rest is essential for the month following treatment because heartworm fragments may circulate into the lungs during this time. Eventually the pieces are eliminated by the body, but if they are dislodged, your dog may suffer heart or respiratory failure.

After about a month, your dog will need to return to the hospital for a day to be treated for microfilariae, the offspring of the heartworms. This stage may need to be repeated if all microfilariae are not killed.

Dogs with severe heartworm disease may not tolerate the treatment to kill the heartworms. In this case, it may be safer to treat the resulting organ failure than to try to kill the heartworms. Dogs in this acute stage will likely not survive more than a few months.

Our veterinarian will recommend the safest and most effective treatment protocol, which will depend on the severity of the disease and the results of treatment and testing.

Today, more than 95 percent of dogs with heartworm disease are treated successfully. Most are cured by medications, but rare cases require surgery. In any case, early detection and ongoing prevention guards against needless suffering.

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