Heartworm disease is one of the most serious and most preventable diseases veterinarians see in dogs. Unfortunately, here in Maryland, heartworm is becoming increasingly common. Every year, we diagnose dogs that have never missed a prevention and many more that have gone months or years without protection.

Our goal at Homeward Bound Veterinary Services is to prevent this devastating disease before it can cause permanent damage to your pet.

What Is Heartworm Disease?

Heartworm disease is caused by a parasite called Dirofilaria immitis. The parasite is spread by mosquitoes, meaning your dog does not have to come into contact with another dog to become infected.

When an infected mosquito bites your pet, microscopic larvae enter the body. Over the next several months, those larvae mature into adult heartworms that live within the heart and pulmonary arteries.

Adult heartworms can grow to more than 12 inches long and live for years inside a dog’s heart and lungs.

Is Heartworm Common in Maryland?

It is becoming more common. Maryland has a mosquito population and a climate that allows mosquitoes to remain active for much of the year. Because of this, Homeward Bound Veterinary Services and other local veterinary practices diagnose heartworm disease regularly.

Many owners assume their dog is “safe” because they spend most of their time indoors. Unfortunately, mosquitoes frequently enter homes, making indoor pets susceptible as well.

What Happens to Dogs with Heartworm Disease?

As heartworms grow, they begin damaging the heart, lungs, and blood vessels. Early signs may include:

• Mild coughing
• Decreased energy
• Fatigue during walks
• Exercise intolerance

As the disease progresses, dogs may develop:

• Weight loss
• Difficulty breathing
• Collapse
• Heart failure
• Severe lung disease

In advanced cases, heartworm disease can become life-threatening.

Why Heartworm Prevention Is Better Than Treatment

One of the biggest misconceptions is that heartworm disease is “easy to treat.” Treatment is possible, but it is expensive, lengthy, and not without risk.

Heartworm treatment involves:

• Multiple veterinary visits
• Blood testing
• Chest radiographs
• Strict exercise restriction
• Several months of medications
• A series of specialized injections designed to kill the adult worms

Even after successful treatment, many dogs are left with permanent damage to their heart and lungs. Preventing heartworm disease is far safer, less stressful, and significantly less expensive than treating it.

Why Exercise Restriction Is Important for Heartworm-Positive Dogs

Many owners are surprised to learn that dogs receiving heartworm treatment must remain extremely quiet. As adult worms die, they break apart and travel through the pulmonary arteries. Increased activity raises the risk of life-threatening complications.

For this reason, dogs undergoing treatment are often restricted to leash walks only for several months. This is one of the most challenging parts of treatment for both pets and owners.

Can Cats Get Heartworm Disease?

Yes. Although cats are not the natural host for heartworms, infection can still occur. Even a small number of worms can cause significant respiratory disease or sudden death.

Unfortunately, there is no approved treatment to eliminate adult heartworms in cats, making prevention especially important.

How Is Heartworm Disease Diagnosed?

Most dogs are screened with a simple blood test during their annual wellness visit. Because it takes several months for heartworms to mature, newly infected dogs may initially test negative. This is one reason routine annual testing remains important, even for dogs receiving prevention.

The Best Heartworm Protection Is Year-Round Prevention

Modern heartworm preventives are extremely safe and effective when given consistently. Missing doses allows immature heartworms to continue developing, placing your dog at risk. Year-round prevention also helps protect against intestinal parasites, depending on the product prescribed.

Frequently Asked Questions About Heartworms

My dog never leaves the yard. Do they still need prevention?

Yes. Mosquitoes do not respect fences.

My dog stays indoors. Do they still need prevention?

Indoor dogs are still bitten by mosquitoes that enter homes, garages, and screened porches.

Can heartworm disease be cured?

Treatment is available for dogs, but it is lengthy, expensive, and carries risks. Prevention remains the safest option.

Is heartworm prevention really necessary all year?

Yes. Maryland’s mosquito season has become longer, and year-round prevention provides the most reliable protection.

Protect Your Best Friend from Heartworm Disease in Bel Air

Heartworm disease is almost entirely preventable, yet we continue to diagnose pets every year that could have been protected with routine preventive care.

If your pet is due for a heartworm test or needs to restart prevention, contact our team at Homeward Bound Veterinary Services. We’ll recommend the best preventive option for your pet’s lifestyle and ensure they stay protected throughout the year.

A simple preventive today can spare your pet months of treatment and potentially save their life tomorrow.