Pet Points: Heartworm prevention for cats and dogs

Heartworm disease is as horrible as it sounds


DETROIT – What are the latest recommendations for preventing heartworm disease in my dog and cat?

With summer fading away and temperatures cooling down, many people may be considering stopping their monthly heartworm preventative for the winter. While many pet owners associate heartworm disease with the onset of spring, the American Heartworm Society has made clear recommendations to maintain dogs and cats on year-round heartworm preventative.

Heartworm disease is as horrible as it sounds. Through a simple mosquito bite, worms infect an animal, travel through the tissues into the bloodstream, and once mature end up in the pulmonary arteries, heart, and lungs. The worms can grow to be anywhere from 4 to 12 inches long, can cause severe damage to the lungs and arteries and in some cases can lead to heart failure and the death of the animal.

The Michigan Humane Society treats many dogs in each of our veterinary clinics each year, but we also find that many of the dogs that are surrendered to us or come into our animal care centers as strays are infected with heartworm. MHS does treat dogs for heartworm, but it is a very expensive, time consuming and difficult process.

Ronaldo, the bulldog pictured above, is one of the dogs who MHS is currently treating for heartworm. Ronaldo came into our care as a stray, and was very skinny and anemic. He had to battle an upper respiratory infection as well as gain some weight before he was healthy enough to begin heartworm treatment. He is currently on medications to prepare him for the treatment and will receive his first injection in about two weeks.

Dogs like Ronaldo, who are living on the streets and exposed to the elements, are especially at risk for heartworm. If you own a dog, you have a responsibility to keep them from being infected. Ronaldo had no caregiver looking out for him. If you already give your dog monthly heartworm preventative – keep it up! Heartworm is a deadly disease but can be prevented simply by giving a medication once a month. This medication can be prescribed by your veterinarian after a blood test to determine that your dog is not infected with heartworm.

The heartworm treatment process involves a series of intramuscular injections that are designed to kill the worms that are living in the vessels of the heart. While the worms are dying off, the dog's body must break them down and process them slowly. Because of this, dogs must be very calm and inactive during the treatment (usually about 6-8 weeks) in order to keep their heart rate down and to help prevent complications from the treatment.

We will follow up with Ronaldo in a couple of weeks on this blog, so readers can see the difficult process of treating heartworm, and how it negatively impacts the dog going through treatment. Prevention is much easier than treating the disease, and much cheaper.

Learn more about heartworm here: https://www.heartwormsociety.org/pet-owner-resources/heartworm-basics

If you are interested in adopting Ronaldo, email gvannini@michiganhumane.org for more information.