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Heartworm Disease in Dogs


Boomer came to live at the Central Dakota Humane Society as a Hurricane Katrina rescue suffering from Heartworm disease. He successfully completed the course of treatment for this preventable affliction, and today this short-legged, long-bodied boy is healthy as a horse. His story prompted the following article.

Heartworm disease is caused by a parasite carried by infected mosquitoes that can affect dogs, cats, and in rare cases, even people. Our canine companions are most often contaminated by the parasite. Once bitten by an infected mosquito, the parasite is released into the bloodstream of its victim. The immature heartworms migrate to the heart and lungs as they develop over the next few months. Once mature, the worms live in the heart and eventually interfere with the heart's ability to pump blood to the rest of the body. Consequently, the heart and lungs fail to function properly and the dog becomes very sick. Some dogs may not show any obvious signs of being infected while others will cough and tire easily with exercise. Severe heartworm infections may cause weight loss and fluid in the abdomen due to congestive heart failure. Heartworm can be spread when mosquitoes feeding on an infected dog pick up the parasite and then transmit the disease to another victim.

It is very important to have your pet tested for heartworm infestation in the spring to prepare for the mosquito season. A simple blood test administered by your veterinarian is required to determine if your pet is heartworm free. If your companion animal tests negative, you may proceed with the heartworm preventive medication prescribed by your vet. On the other hand, if your pet tests positive for a heartworm infestation, immediate treatment by your veterinarian is required. Most infected dogs have serious, potentially life-threatening complications that can occur even if there are a lack of symptoms.

Dogs with Heartworm disease should be treated with medication to kill the heartworms unless they have a medical condition that prevents treatment. Most patients are hospitalized and given a series of injections to slowly kill the adult worms. The process of killing the worms takes an average of two to four weeks. During this time, it is critical to keep the dog confined and to restrict exercise for a minimum of four to six weeks so that the dying worms won't break free and form a blockage in the dog's lungs. Dogs who require treatment should be retested for heartworms approximately four months after the treatment to confirm that all worms were killed. Occasionally, a second treatment is needed to eliminate all the worms.

In the end, having your pet tested for heartworms annually and by using preventative medications recommended by your veterinarian is the best way to ensure your faithful companion is well-protected from this nasty parasite. Prevention is a small price to pay when it comes to the health of your best friend!