Spread by the mosquito, heartworm disease (HWD) affects the heart, lungs, and associated blood vessels of infected animals.

According to the American Heartworm Society, the blood vessels of the lungs are an early target. A mild cough or exercise intolerance is often observed. As the disease progresses and the number of adult heartworm increases, the heart is impacted, which can result in an enlarged heart and ultimately congestive heart failure. The good news is that it can be treated, though early detection and treatment are important. Both indoor and outdoor dogs and cats can get heartworm disease.

In dogs, HWD is detected by a blood test that identifies the presence of a foreign protein substance given off by the worm, also know as an antigen. If your animal tests positive, additional diagnostics utilizing x-rays and echocardiograms, urinalysis and blood profile can show the extent of the disease. Often, an infected animal will show no symptoms, so the heartworm test is essential for early detection. In some cases, your doctor may suggest the SNAP 4Dx heartworm test which also detects Lyme disease, Anaplasmosis, and Ehrlichia (tick borne diseases).

In cats, consequently, HWD usually presents itself differently than in dogs: these parasites often spontaneously die. Occasionally only one or two adult worms survive. Consequentially, detection of their presence can be difficult.  Death of larvae or adult worms elicits an anti-inflammatory reaction.  The death of the adult worms elicits anti-inflammatory condition in the lungs resulting in symptoms similar to asthma or chronic inflammatory disease of the lungs.  Sudden death is also a possibility.

Prevention of heartworm disease is simple. Heartworm preventives such as HeartGard©, Iverhart©, Interceptor©, and Revolution© are all highly effective in dogs. Revolution©, a topically applied product is the drug of choice for cats. While these preventives were once recommended to be given from June through November, it is now the recommendation of the American Heartworm Society and Companion Animal Parasite Council, that year-round preventive care be administered. Because of the similar nature of some intestinal parasites, heartworm preventive can also provide protection against these parasites such as roundworms.