A Heart Full of Spaghetti

By Dr. Anndrea Kapke
www.olivebranchvet.com
olivebranchvet@gmail.com

In veterinary school, I had a pathology professor who told us never to describe disease processes using food terms. But I can’t help it; heartworm disease doesn’t look like anything other than a heart full of spaghetti. I hope you weren’t planning to have pasta tonight.
Heartworm disease most commonly affects dogs. Cats may also get the disease, but the disease is quite different in them. Rarely, immunocompromised humans will get heartworm disease.
Heartworm disease is spread by infected mosquitoes. When the infected mosquito bites a dog it injects tiny heartworms into the dog’s blood. It is the goal of all baby heartworms to move into the penthouse of the blood vessels in the lungs and maybe even the right side of the heart when they grow up.
A dog with early heartworm disease or maybe only a few heartworms, won’t appear sick. Later the dog may have a chronic cough, not want to play or eat much and may lose weight. In advanced heartworm disease, you can imagine a heart can’t pump blood very efficiently when it is full of spaghetti-like worms. Fluid ends up backing up and the dog may develop a pot belly full of fluid. Eventually the dog will die from heart and liver failure.
Veterinarians look for heartworms with a blood test. Most dogs with heartworm disease can be treated and cured of the disease. However, the treatment is expensive, time consuming and not without risk. There is a chance that the medication used to kill the heartworms will kill too many heartworms too quickly. The dead worms may then float down (blood) stream like sticks into a beaver dam. A blocked blood stream is called an embolism. Things downstream of the embolism don’t get any oxygen. This is pretty bad, especially if the organ downstream is the heart or brain.
It is always easier to prevent a disease than to treat it. There are many brands of heartworm preventative currently available. In Indiana, I recommend giving your dog or outside cat heartworm preventative once a month all year. Our weather is too unpredictable to assume that all mosquitoes will be killed during the same months of every year.
Why does your veterinarian make you bring your dog in for a heartworm test before refilling the heartworm preventative each year? Three reasons. 1. Even I sometimes forget to give my dogs their heartworm preventative and I do this for a living. 2. I can’t think of a medication that is 100% effective on 100% of patients. 3. If a dog with heartworm disease is given heartworm preventative and all the microfilaria (baby heartworms in the bloodstream dreaming of the good life in the lungs and heart) are killed at once, there is a slight risk of the dog’s body producing a fatal reaction to the dead worms.
So, the next time you sit down to a big dish of spaghetti and tomato sauce with meatballs be sure to ask yourself, “Did I give Fido his heartworm preventative this month?” And have I talked to you about neutering?