Heartworm disease is a complicated topic for pet owners, but prevention is easy. The Westerville Veterinary Clinic team has compiled the following facts to help you protect your pet from this devastating but avoidable disease.

#1: Heartworm disease is a life-threatening but preventable condition in pets

Heartworm infection is nearly 100% avoidable when your pet is on year-round heartworm prevention, plus annual screening tests. These tests can identify hidden or early stage infection, providing your dog with additional protection and increasing their survival chances, and offering you peace of mind.

#2: Heartworm disease is transmitted when an infected mosquito bites your pet

Mosquitoes are infamous for their disease-carrying capabilities, but this pesky pest does more than transport heartworm disease—it’s a critical part of the heartworm maturation process. 

Mosquitoes acquire heartworm larvae while feeding on an infected pet. The juvenile worms (i.e., microfilariae) pass through key life stages inside the mosquito and are then transmitted to another pet that the mosquito bites. If that pet is a suitable host, the microfilariae mature into adult worms. 

#3: Heartworm disease is present in all 50 states and can infect indoor pets

Heartworm disease was once confined to the warm climates of the southeastern United States, but now affects more than one million pets in all 50 states. 

Indoor pets are not immune—mosquitoes can slip through doorways, crawl through open windows, or hide in garages and basements and feed on your unsuspecting pet. These pets are uncomplicated hosts, because many are not receiving a heartworm preventive.

#4: Dogs and cats experience heartworm disease differently

Dogs are natural heartworm disease hosts. Like wild carriers, such as foxes and coyotes, the dog’s internal processes support heartworm life and maturation, so the microfilariae can grow into adult worms, reproduce, and cause devastating heart and lung issues.

Cats are atypical or unnatural heartworm hosts, meaning their internal environment is less suitable to heartworm development and many microfilariae don’t survive. Unfortunately, however, only one or two adult worms can cause life-threatening harm because the cat’s heart is so small.

#5: Heartworms damage your pet’s heart, lungs, and arteries

Adult heartworms are spaghetti-shaped and up to 12 inches long. The heartworm’s whip-like body damages vessel and organ walls by sparking harmful inflammation and irritation, while gathered worms can block normal blood flow or form a dangerous clot-like blockage.

Prolonged interference with natural blood flow can cause irreversible changes in the heart muscle, lung tissue, and circulatory system, and alter the body’s ability to receive life-sustaining oxygen.

#6: Heartworm disease signs can vary in pets

Heartworms take up to six months to complete their life cycle, beginning with a two-month migration from the bite site through the tissues to the lungs and heart. Affected dogs and cats may appear completely normal for several months until their infection reaches critical mass.

Dogs suffering from heartworm disease typically experience a persistent cough, exercise intolerance, fatigue after mild activity, inappetence, weight loss, and a pot-bellied appearance. Cat signs can range from subtle or nonexistent to severe, and may include asthma-like attacks, coughing, weight loss, and inappetence, or unexplained collapse and sudden death.

#7: Heartworm treatment is available only for dogs

Heartworm disease treatment is available only for dogs and requires hospitalized care and prolonged rest at home. Treatment is most successful in asymptomatic dogs in the early disease stages. Dogs with a heavy worm burden are at greater treatment complication risk and may suffer permanent organ damage.

Canine heartworm treatment includes a series of intramuscular melarsomine injections that kill circulating adult heartworms—which can number in the hundreds—so the body can move them out of circulation. Dogs must be kept on strict crate rest for several months to avoid treatment-related complications (e.g., further irritation, blockages caused by the dead and dying worms).

#8: Heartworm-positive cats may benefit from supportive care

No safe treatment is available for heartworm-positive cats. If your cat is diagnosed with heartworm disease, your veterinarian will likely recommend supportive care to keep them comfortable and manage their clinical signs, and explain how you should monitor their condition at home. 

As atypical carriers, cats may spontaneously clear their infection on their own or may outlive the infection altogether because of their small adult worm burden.

#9: Annual testing enhances heartworm protection in dogs

Yearly heartworm screening tests are recommended for all dogs, including those on year-round heartworm prevention. Heartworm tests are a simple blood test that detects heartworm antibodies in your pet’s circulation—a powerful indicator of hidden disease. Early diagnosis allows for more rapid treatment and improves your dog’s outcome by minimizing organ damage and irreversible injury.  

#10: Year-round prevention is essential for all pets

Heartworm disease doesn’t take a holiday, and neither should your pet’s parasite prevention. Mosquitoes can emerge from dormancy on mild winter days or overwinter in basements and garages—so pausing or postponing your pet’s preventives during cold weather months is unwise.

The Westerville Veterinary Clinic veterinarians understand that year-round preventives can be expensive. Our platinum wellness plan includes deep discounts on veterinarian-recommended preventives—so you can easily ensure your pet is always protected against heartworms and other parasites. 

If your pet is due for their annual heartworm test or needs to start or restart a parasite prevention regimen, contact our team and schedule an appointment.