Heartworm Awareness

Heartworm can be a deadly, but easily preventable, disease for dogs. Dogs are considered the definitive host for heartworms, although they can infect over thirty species including humans and cats, as well as wild canines and felines. The larvae of the parasite are transmitted by infected mosquitoes when they bite a dog. The larvae are injected into the bloodstream of the host where they grow and develop as they migrate in the body for several months. Once mature, they reside in the heart, lung, and associated blood vessels. Females release offspring, called microfilariae, into the bloodstream. The number of worms in an infected dog can range from one to 250, with male worms averaging four to six inches in length and females between ten and twelve inches. All dogs, regardless of their age, gender, or lifestyle, are susceptible to it. Heartworm infection has been found in dogs native to all fifty states.

Symptoms of heartworm disease include cough, difficult breathing, and exercise intolerance. In most dogs, the heart and lungs are the major organs affected with varying degrees of clinical signs. Diagnosis is through a combination of a pet's history, bloodwork, and x-rays. Blood testing will detect the presence of microfilariae or antigens that signify adult heartworms. Testing can come back negative if an infection is less than 6 months old. The American Heartworm Society recommends yearly testing for all dogs across the country, even those on preventatives. Radiographs will show abnormalities that develop early in the course of the disease and are also an effective tool for determining the severity of an infection.

If a dog is diagnosed with heartworm, treatment will involve the administration of an FDA approved adulticide, during which hospitalization may be necessary. Additionally, giving heartworm preventatives will eliminate any microfilariae in the bloodstream. Treatment can involve several visits to the veterinarian, with retesting after treatment.

While treatment is usually successful, prevention is much safer and economical. There are many options on the market, most of them given monthly in the form of a topical application or a chewable tablet. These preventatives are very effective when used correctly. The American Heartworm Society recommends year round preventatives for dogs all around the country, regardless of lifestyle or age. Before beginning a preventative program, a visit to the veterinarian for a heartworm test will make sure your dog is not currently infected with heartworm. It will also allow you to discuss with your dog's doctor the best preventative program for you to implement.

For further information, here is a link to the American Heartworm Society's web page: