Heartworm Disease

What is heartworm disease?

Heartworm disease is considered to be one of the major canine health problems in our country

Heartworm disease is a serious disease caused by infection with a parasitic worm that lives in the heart and adjacent large blood vessels of the lung. A dog can be infected with one to several hundred adult heartworms, which may grow in length of 6-14 inches. Infection has spread rapidly throughout the United States in the past two decades, and heartworm disease is considered to be one of the major canine health problems in our country.

The Mosquito Connection

Heartworms are transmitted from one dog to another by several species of mosquitoes. After a dog is bitten by an infected mosquito, it takes approximately 6 months for the heartworm larvae to reach the arteries of the lung and are then released into the bloodstream. Because the metropolitan DC-VA-MD areas are highly populated with mosquitoes, heartworm disease is a prolific problem in our area.

Adult v. Microfilaria

There are adult heartworms that live primarily in the heart and other organs, and microfilaria which are the young heartworm larvae that travel throughout the bloodstream. Both are dangerous and both cause life-threatening problems in your dog. To see pictures of heartworms, click here (warning - graphic pictures).

The Damage

Heartworm infection results in extensive damage to the arteries of the lung, heart, liver and kidneys. Much of the damage occurs before there are any outward signs of the disease, and the disease if more difficult to treat by the time the signs are seen. In advanced cases, the prospect of complete recovery is reduced even though treatment may kill all the adult worms. Heartworm treatment is very hard on your dog and many do not live through the treatment.

Testing for Heartworms

Your vet can detect the infection by examining a sample of your dog’s blood or an immunologic test for substances. X-rays can also be helpful in recognizing adult heartworms. Your dog should be tested for heartworms as part of their yearly veterinary exam.

Prevention is the Answer

Heartworm disease is completely preventable. As a dog owner, it is your responsibility to prevent this disease. <div class='pullquote'>Labs adopted through LRR are required by the Adoption Contract to receive monthly heartworm preventative medicine</div> - we believe that strongly in it. Preventative medications come in daily and monthly doses and are prescribed by a veterinarian. One small dosage of this medication on a regular basis can save your dog’s life. Get your dog tested for this terrible disease and administer preventative medicine regularly. Only you can prevent heartworms.


American Heartworm Society, P.O. Box 667, Batavia, IL 60510, http://www.heartwormsociety.org/

American Veterinary Medical Association, http://www.avma.org/careforanimals/CFAsiteindex.asp

DISCLAIMER: This article reflects the opinion of LRR, Inc. and should not be considered as professional advice. These articles are not written by professionals, such as veterinarians or behaviorists, but by LRR volunteers. It is always recommended that you seek the advice of a professional for behavior and health issues.

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