Heartworms and Your Dog and Cat

Heartworms are an actual worm that is transmitted to our pets via the mosquito. If you are a dog owner, I am sure you have heard of this disease. But I am also including this in the cat section because there is now good evidence that Heartworms affect cats as well.

Heartworms are blood parasites that are transmitted from animal to animal via the mosquito, and as they develop the adult worm (which looks just like a piece of spaghetti) actually lives in the top area of the heart and the large pulmonary artery that leaves the heart and goes to the lungs. In really bad cases, the worms can even clog up the vena cava, the large vein that brings blood back to the heart from the rest of the body.

This is a dangerous disease. The worms affect the heart, the lungs, and take a real toll on the pet. The treatment is very strong because we have to inject the pets with poisons that kill the worms. As a matter of fact, we cannot use this treatment in cats because the treatment can be worse than the disease. So there really is NO treatment we can use for cats if they get this disease. The main symptom of Heartworm disease in the dog is coughing. In the cat, we may see coughing and/or vomiting. Unfortunately, sometimes we see no symptoms in cats until it is too late; Heartworms are one of the causes of sudden death in the cat.

The good news is that this is a very easy disease to prevent. Before we had the preventive medications, in endemic areas of the country (basically east of the Mississippi River) as many as 90% of the dog population tested positive for Heartworms. Since we have been using the preventives, this number has declined to well below 5% in many of those areas. And we are just now studying the percentages of cats that may be affected by this disease. No one has yet come up with complete information, and I will keep you posted as the research develops.

So here are the Dr. Larry pearls of wisdom:

1) Every dog, everywhere in the country, should be placed on one of the Heartworm preventives at 8 weeks of age. There are two products, Heartgard and Interceptor, which are both very good. They are described in the Product Area in more detail.

2) Every dog should have a Heartworm test performed either every year or at a minimum of every other year, to be sure you can detect the disease at an early stage.

3) It is now a good idea to place all cats in endemic areas, even indoor cats, on the Heartgard preventive for cats. Because there is no treatment for cats and the preventive is safe and effective, there really is no reason not to place them on the Heartgard.

Talk to your veterinarian about Heartworm disease. Follow the recommendations that they make to you. This is a very tough disease that we have really been able to successfully defend against. Preventive medicine is really the key. As always, helping your petÉand their people, too.

Dr. Larry