Heartworm disease in cats is getting a lot of attention lately. Veterinarians are gaining a better understanding of how heartworms cause disease in cats, and it is different from dogs.
Heartworm infection takes place when an infected mosquito bites a cat and the larvae mature in the blood vessels that supply blood to the lungs. These maturing larvae cause an inflammatory reaction. Respiratory signs associated with this inflammatory reaction are termed Heartworm Associated Respiratory Disease (HARD). Unlike heartworm disease in dogs where mature heartworms cause the most problems, in cats the larvae cause significant problems in the lungs by causing severe inflammation. Signs heartworm positive cats exhibit, such as coughing, difficulty breathing, not eating, fainting, and the like, may be mistaken for other common feline conditions like asthma, bronchitis, or other respiratory disease. Heartworm disease is also difficult to detect in cats since negative test results do not rule out heartworm disease.
Common Misunderstandings About Heartworm:
|Heartworm affects dogs only - FALSE
Heartworm does not affect indoor-only cats - FALSE
Heartworm disease is exclusively a heart disease - FALSE
Only adult heartworms cause problems in cats- FALSE
The consensus of veterinary experts is that heartworm is more common than previously thought and that prevention is truly a cat owner’s best bet.
How is heartworm disease in cats diagnosed?
To diagnose heartworm disease in cats that are showing signs of disease, both antibody and antigen blood tests are done. These, however, are difficult to interpret in cats, and can show negative results when the animal is really infected. So, x-rays and ultrasounds (echocardiography) are also performed.
What is included in a good heartworm prevention program?
The best program for prevention of heartworm infection includes using preventives, performing heartworm testing as recommended and reducing exposure to mosquitoes. Every cat, whether indoor or outdoor, should be on a heartworm preventive. Cats should be tested before they are started on a preventive. They should also be tested if they are showing any signs of heartworm associated respiratory disease.
Medications used to prevent heartworm infections are called preventives. The first thing to remember is that preventives are NOT used to kill the adult worms. Special drugs called adulticides must be used to kill the adults. Heartworm adulticides are not approved for use in cats, so prevention is especially important.