Heartworm disease is a potentially fatal parasitic infection that occurs in our dog and cat companions. Heartworms are transmitted through the bite of an infected mosquito. Once inside the dog’s body, the baby heartworms develop into adults and make their way to the pulmonary arteries. Although they are called 'heart' worms, these parasites prefer to live in the large arteries carrying blood from the right side of the heart to the lungs. These worms cause a severe inflammatory response as well as embolisms (blood clots) in the lungs. If the worm burden becomes high, they will back up into the right side of the heart. If there are a lot of worms, it becomes very difficult for the heart to pump blood through the clogged arteries. These problems are manifested as coughing, exercise intolerance, difficulty or labored breathing. When the worm burden reaches maximum capacity, the worms take up so much room that there is little space left over for blood to circulate through the heart. This is called 'Caval Syndrome', which most dogs do not survive.
On average, local clinics diagnose heartworm 12 months out of the year. Heartworm preventative, available at your local veterinarian, kills the baby heartworms transmitted by the mosquito. There are many options for heartworm prevention. Common selections include, a monthly pill, combination medications that fight both heartworms and fleas, and an injection (given every 6 months). All dogs and cats should be on heartworm preventative year round.
A simple blood test is used to diagnose a heartworm infection. If your dog is heartworm positive there is a treatment available. In order to kill the heartworms, a strong arsenic-based injection must be used. The treatment period often takes up to 60 days, during which time the patient needs to be confined (often crated) to prevent life threatening complications. Given the damaging nature of this disease and the complicated (and usually costly) nature of treatment, it is always better to be proactive in preventing an infection by using monthly heartworm prevention.
For more information please contact your veterinarian.
Posted Friday, April 17, 2015