Heartworm Facts

posted: by: AAC Tags: "Clinic Specials" "News" 

1.                  Adult heartworms live in the right side of the heart.  They are 6 - 14 inches long. Several hundred may be present in the dog!

2.                  Heartworms impair blood circulation resulting in damage to the heart, lungs, liver, and kidneys. Serious damage may occur even before outward clinical signs are observed.

3.                  Advanced signs include difficulty breathing, coughing, tiring easily, listlessness, weight loss, and fainting.

4.                  Heartworms are found throughout the United States and Canada.

5.                  Heartworms are spread by MOSQUITOS.  Microscopic microfilarias ("baby" heartworms) are ingested by mosquitos during a blood meal on an infected dog or cat. The microfilaria become infectious inside the mosquito and is transmitted to another dog or cat when it is bitten by the infected mosquito. At first, the parasites move into your pet's tissues and eventually migrate to your pet's heart where they take up occupancy.  As the worms grow and reproduce, more immature worms are released into your pet's bloodstream.  When other mosquitos bite your dog they pick up these new immature worms and transmit them to the next dog that they bite.

6.                  It takes 3-6 months for adult heartworms to develop in the dog after being bitten by an infected mosquito.

7.                  Heartworms occur in ALL breeds of dogs and cats: both large and small, short-haired and long-haired, inside-pets and outside pets.

8.                  Diagnosis of Heartworms is by a blood test.  Annual blood tests are recommended for all dogs including those on preventative medications because none are 100% effective.

9.                  Treatment is very SUCCESSFUL when the disease is detected early.

10.              Treatment begins with a COMPLETE physical and medical examination to determine the health status of your pet and the severity of the disease.  Laboratory tests and X-rays may be ordered as part of a             complete work-up to help assure treatment tailored to your dog's condition.

                 Heartworms can be treated with a medication that is the most effective development in adult heartworm control in 50 years. Most heartworm-infected dogs need 2 injections of this medication, given 24 hours apart.  Your dog will be kept in the hospital for this procedure, and will be carefully monitored.  Supportive medications may be administered as necessary on a case-by-case basis.

                 In most cases, after the second injection, your dog may be released from hospitalization. However, your pet's condition and your veterinarian's judgment will best determine when your pet may go home.            Total rest is absolutely necessary for your pet once released from hospitalization to prevent complications resulting from stress on the heart and lungs.  Your dog must be kept quiet for 4 to 6 weeks following       heartworm treatment.  For most dogs, staying indoors is sufficient.  Very active dogs may need to be more closely confined. Please check with your veterinarian before you allow your dog to resume regular exercise.

11.       Heartworm disease and treatment are serious matters requiring close monitoring of your pet during treatment and home convalescence.  As the worms within the heart and circulatory system are   eliminated, some dogs experience a temporary lack of appetite, upset stomach, drooling, or panting. Signs of fever, respiratory difficulty, or depression also may occur in response to the presence of dead worms. If these or other signs of discomfort develop, please call your veterinarian, who will see that your pet gets appropriate care.


            Heartworms are easily transmitted by mosquitos, having them once does not make your dog immune. One month after your dog was hospitalized for adult heartworm treatment, he/she should be readmitted to begin the preventative phase. Your veterinarian will complete a physical exam to see if your dog is ready to begin prevention. A micofilaricide preventative will be administered and your dog will be monitored for   reactions for the day. If no reactions occur, your dog will be discharged at the end of the day with instructions to gradually return to regular activity.  Your veterinarian will recommend a monthly heartworm preventative to go home with your dog.

13.       Maintaining your dog on monthly heartworm prevention is the most effective way of protecting your pet from future heartworm disease and the potential for organ damage that may shorten his/her life.