Heart Worm Disease
What is heartworm disease? An infection with a filarid worm, Dirofilaria immitis, which is about the size of a pencil lead (from 4-12 inches long) and lives in the heart of dogs and other canines.
How does heartworm disease affect the dog? The dog will tire more easily, may cough, and show general signs of illness. However, in Indiana, many dogs will have light infections which, in the early stages, will show no outward clinical signs that the owner can recognize.
How does my dog get heartworm disease? Microfilaria are the larval form of the heartworm which are in an infected dog's blood stream. These are transmitted to other dogs by mosquitoes.
If my dog gets heartworm disease, can he be treated? Yes. Most dogs survive with little or no after effects if they are treated early, but prevention is best and much less costly.
Do well-cared-for dogs ever get heartworm disease? Yes. About 4 % of the dogs tested by veterinarians have heartworm disease. However, this number can be reduced to near zero with proper preventative care.
What shall I do as a dog owner in Indiana to prevent my dog from getting heartworm disease? It's really very simple.
1. Have your dog checked for heartworm disease every spring by your veterinarian.
2. Give the preventative medication prescribed by your veterinarian.
I have heard that cats can get heartworm disease. Is this true? Yes. Cats and other unnatural hosts can contract heartworm disease, however the infection involves fewer worms. Cats unfortunately react to a small number of worms to a greater extent than do canines. Therefore, cats can have severe symptoms. The symptoms most often seen are coughing, vomiting, labored breathing and fatigue. It has been estimated that the level of heartworm disease in cats is somewhat less, but parallels the endemic level of heartworm disease seen in coyotes, foxes, and stray dogs. In the state of Indiana, 17% of coyotes, foxes, and stray dogs have heartworms. The tests for heartworm disease in cats are now quite reliable, but, only work if the cat has enough worms to cause the test to be positive. Some cats can be quite ill with heartworm disease and still not cause the test to turn positive because of a low worm burden. Therefore, it is recommended that cats be tested and put on preventative medications in the same manner as dogs.
Can heartworm disease be transmitted to people? The human is an unnatural host for the heartworm. A few people have been found to have contracted heartworms. Most have only one worm which appears as a coin lesion on a chest x-ray study. The worm has been walled off by the tissues in the lung, and by the time the diagnosis is made, the worm is usually dead. A biopsy is often done to be sure the coin lesion (round spot on the x-ray) does not represent cancer. A total of two people in the State of Indiana are known to have had canine heartworms in recorded history. Neither suffered serious problems as a result. To put that into perspective, 6 million people live in Indiana and only two contracted the disease. Your chances of contracting heartworm disease in Indiana are very low indead. Your chances of being struck by lightning are considerably greater; therefore, human heartworm disease does not merit concern.