Feline Heartworm Disease

Canine and Feline Heartworm Disease share only one similarity…both are transmitted by the mosquito. Florida ranks first in the country for heartworm disease in both the dog and cat.

Past teaching in veterinary colleges was that when cats got this disease, it would cause only a transient illness and the patient would fully recover. However, over the past few years, research has shown about 30% of all cats either have been exposed or possess the disease. Indoor cats are more susceptible than outdoor cats to heartworms.

Symptoms include vomiting, asthma like symptoms, lethargy and poor appetite. In some patients however, there are no symptoms and death is sudden. In canine disease, as many as 50 to 100 worms may reside in the right heart ventricle and pulmonary arteries whereas cats may only have 1 to 2 worms in the lungs. Hence, a common symptom is an asthma like syndrome.

Currently, supportive care is the only treatment.Some patients will respond and recover and others will not. Unlike canine heartworm disease, testing is unreliable. Two tests currently available are the Antigen (detects heartworm material in the patient’s body) and the Antibody (examines the patient’s immune system for heartworm exposure). A positive or negative response to either or both tests does not rule in or out heartworm disease. In most positive tests cases, the patient has only been exposed to the disease and infection never occurred. Usually, further testing such as radiographs and bloodwork are required to fully assess the disease status.

Although there is no cure for this potentially deadly disease, there are two preventatives available: Heartguard (ivermectin) which is a chewable product given every 30 days that most cats dislike and Revolution (selamectin) which is a topical product also used every 30 days. Revolution not only prevents heartworm disease, but also treats fleas, ticks, ear mites, intestinal parasites and skin scabies. It is very easy to apply and should be used every 30 days. Unlike canine heartworm disease, Revolution may be used regardless of heartworm status. That is, the dog must have a negative heartworm test result prior to using prevention, whereas in the cat, it is not necessary.

If you have any questions to this puzzling disease, please don’t hesitate to call the clinic.