Canine Heartworm Disease

The Southern states rank first in the nation for heartworm infection (Dirofilaria Immitis). Florida is first among the southern states and therefore first in the nation for this deadly disease.

The mosquito transmits heartworm disease. This occurs by a mosquito obtaining a blood meal from an infected dog and then injecting the larvae in a non infected animal. Over a 6 month period, the larvae develop into adult heartworms and reside in the right side of the heart and vessels leading to the lungs. Adult heartworms begin to produce microfilaria (baby heartworms) which will also develop into adults in about 4 to 6 months. If the infection is allowed to continue, the dog will die from right sided heart failure or a complication thereof.

Diagnosis is quick and easy. The American Heartworm Association recommends an antigen (occult) heartworm test be performed once to twice yearly depending on location and incidence of heartworm disease. The antigen (occult) tests for adult heartworm protein in the patient’s blood. It takes 10 minutes and is virtually 100% specific. Ninety-nine percent of dogs with mature heartworm infection are antigen positive (have an infection). It is imperative your pet be tested at least yearly for heartworms even if you are diligent about giving prevention once monthly. Giving an infected pet heartworm prevention can be lethal and I have seen it occur throughout my career.

There are several heartworm preventatives on the market. Two products we carry are Heartgaurd Plus (Ivermectin/Pyrantel) and Revolution (Selamectin). Heartgaurd is a once a month chewable preventative for heartworms and also intestinal parasites. It does not provide flea or tick prevention. Revolution is the newest product on the market and is applied once a month topically to the skin. It provides heartworm, intestinal parasite, flea, tick, ear mite and skin scabies protection. As with all preventatives however, nothing is 100% effective and is why testing is necessary at least yearly.

We treat 5 to 6 cases a year for heartworm disease costing the owners $400 to $600 per case. Not only is it much less expensive to use a preventative, but also obviously better for your pet. If you have any questions regarding heartworm disease or prevention, feel free to contact the office.