Heartworm disease is preventable.

One of the most common questions is, “If I give my dog heartworm prevention, why do I need to have them tested?” This is an excellent question, and we would like to answer it by explaining the heartworm life cycle and how prevention works. We hope this will also answer any other questions you may have regarding protecting your pet from these deadly parasites.

Heartworms are transmitted from one dog to another by a mosquito. When a mosquito bites a dog infected with heartworms, then bites your dog, it transmits the heartworm larva into your dog’s bloodstream (it only takes one bite!)

Over six months, the larva matures into an adult worm

Adult worms can live an average of six to seven years inside your dog, causing permanent damage to the heart and lungs.

When we test your dog for heartworms, we draw a small amount of blood and perform what’s called an occult test, which detects the presence of adult female worms.

We also look at a blood sample under a microscope to screen for microfilaria, which are immature heartworms.

Adult dogs over 7 months of age and previously not on a preventive need to be tested prior to starting heartworm prevention, and retested 6 months later and annually after that.

Also, if there has been any lapse in prevention, your dog should be retested 6 months after starting back on prevention.

Giving preventatives to a heartworm-positive dog can lead to rare but possibly severe reactions that could be harmful or even fatal.

While cats can be infected with heartworms, they are not a primary host and typically only have one to three worms (while dogs can have hundreds!).

Heartworms and Cats

Since a heartworm test only detects female worms, diagnosing heartworms in a cat is difficult as the cat may not have a female heartworm for the test to detect.

While cats may not be the primary host, it is still essential to give prevention because no heartworm treatment is available for cats.

Symptoms of heartworms in dogs may include coughing, lethargy, and weight loss, which ultimately leads to heart failure and death. Many people assume that because their pet isn’t showing any signs of illness, it does not have heartworms.

Unfortunately, dogs can be infected with heartworms long before showing any kind of symptoms. With cats, often the first and only symptom is sudden death.

Prevention

Heartworm prevention works by killing the larval stages (immature heartworms) before they mature into adults. Once the larvae reach the juvenile stage, which takes less than two months, they are no longer affected by the heartworm preventative.

This is why oral and topical heartworm prevention must be given monthly. Heartworm prevention is very effective, but if even one dose is missed or your pet vomits the heartworm prevention without you knowing, they are at risk.

There have also been reports of larvae becoming resistant to the active ingredient in heartworm prevention. Because of these reasons, annual heartworm testing is recommended even if a pet is on prevention year-round.

There are numerous different heartworm preventatives available and with various combinations of other intestinal parasite preventatives and some with flea and tick control.

What we recommend

At Zebulon Animal Hospital, we recommend Interceptor Plus for dogs, a flavored chew that protects against heartworms, roundworms, hookworms, whipworms, and tapeworms.

If your dog is difficult to medicate orally or if you are unsure if you can remember to give it monthly, we also offer the Proheart 6 injection, which is administered here at our hospital and protects against heartworms and hookworms.

For cats, we recommend Revolution Plus, a topical monthly preventative that protects against heartworms, roundworms, hookworms, ear mites, fleas, and ticks.

These are prescription products and are available in our hospital or at our online pharmacy here: MyVetStoreOnline

Protecting your pet from heartworms is one of the simplest yet most important things you can do to help give your pet a long and healthy life.

Please visit the American Heartworm Society’s website for more information: https://www.heartwormsociety.org/pet-owner-resources

We serve Zebulon, Griffin, Barnesville, Thomaston, Meansville, Concord, Molena, Williamson, and the surrounding areas.