Heartworms are among the most dangerous parasitic worms that infect dogs. Each year over one million dogs are diagnosed.1 The disease is passed from infected dogs to other dogs by mosquitoes. That means all of these dogs are at risk for heartworm disease.

The disease is spread when a mosquito, previously infected by biting an infected ("reservoir") dog, bites a dog and deposits tiny immature heartworms, called larvae, near the bite wound. Then, the larvae enter the wound and migrate beneath the skin, eventually reaching the heart and lungs. These unwelcome intruders can grow up to 12 inches in length. Heartworm disease is debilitating, and may even prove fatal.


All dogs are potential targets for heartworm disease. In fact, canine heartworm disease has been detected in all 50 states.2

Clinical Signs of Heartworm Disease

An infected dog may cough or wheeze occasionally, and may seem unusually tired and unwilling to play, but these early signs of heartworm disease can easily be missed, and may be mistaken for something else. The only way to tell if your dog has been infected is to have a veterinarian administer a heartworm test.

Treatment of Heartworm Disease

Treatment for heartworm disease is difficult, expensive, lengthy and may be traumatic to dog and owner. Dogs receive a series of arsenic-based shots to kill the worms and must spend up to 6-8 weeks in an environment that will not tax the dog's heart and lungs any further. This may call for crating the animal to limit activity and prevent overexertion.

Prevention of Heartworm Disease

For your patients continuous protection against heartworm disease, it's important to recommend a monthly preventive like HEARTGARD Plus (ivermectin/pyrantel). A single lapse in compliance could give mosquito-borne heartworm larvae the small window of exposure they need to infect a dog.

HEARTGARD (ivermectin) Brand Products for dogs are indicated to prevent canine heartworm disease.

HEARTGARD Plus (ivermectin/pyrantel) is indicated to prevent canine heartworm disease and for the treatment and control of two species of roundworms and three species of hookworms.