Prevention, Diagnosis, and Treatment at Lubbock Animal Medical Center

Heartworm disease is a serious and potentially fatal condition that affects dogs across the United States, including right here in Lubbock, TX. At Lubbock Animal Medical Center, we diagnose, treat, and—most importantly—help pet owners prevent this dangerous parasitic infection through education, testing, and proven prevention methods.

What Are Dog Heartworms?

Heartworms are long, thin, parasitic worms that live in a dog’s heart and major blood vessels. Adult heartworms can grow up to 10–12 inches long and cause severe damage to the heart, lungs, liver, and kidneys.

Heartworm disease is common and, without proper treatment, can be life-threatening. Wild canines—such as foxes, coyotes, and wolves—can also carry the disease, helping spread it throughout the country and increasing the risk to domestic dogs.

How Do Dogs Get Heartworms?

Heartworms are transmitted through mosquito bites. When a mosquito bites an infected animal, it picks up microscopic baby worms called microfilariae. These larvae mature inside the mosquito before being transmitted to another dog when the mosquito bites again.

Once inside a new host, the microfilariae migrate to the heart and lungs, where they mature into adult worms over the course of six months. Mature heartworms reproduce, releasing more microfilariae into the bloodstream—continuing the cycle.

Heartworm disease is found in every U.S. state, though it is more prevalent in coastal and humid regions. According to the American Heartworm Society, cases are rising in non-coastal areas due to shifting weather patterns and the relocation of animals after natural disasters like hurricanes.

Symptoms of Heartworm Disease in Dogs

Heartworms take five to seven years to mature and cause visible symptoms, meaning dogs may be infected long before signs appear. Once symptoms develop, they typically reflect heart and respiratory distress and may include:

• Persistent coughing

• Difficulty breathing or shortness of breath

• Fatigue and reduced energy

• Dull or thinning coat

• Weight loss or decreased appetite

• Abdominal swelling (fluid accumulation)

• Lethargy or fainting

In severe cases, dogs may experience sudden collapse or death. If your dog shows any of these signs, schedule a veterinary examination immediately.

How Is Heartworm Disease Diagnosed?

Our veterinarians use several methods to diagnose heartworm disease in dogs. Often, multiple tests are performed to confirm the diagnosis and determine the severity of infection.

1. Antigen Test

This quick, in-clinic blood test detects the presence of antigens from adult female heartworms. The test provides results in about 10 minutes. However, it can only detect infections with at least five adult female worms and will not detect all-male or immature infections.

2. Microfilaria Test

This test involves examining a drop of blood under a microscope to identify microfilariae (baby heartworms) circulating in the bloodstream. It’s often used to confirm positive antigen results.

3. Echocardiogram (Heart Ultrasound)

In rare cases, an echocardiogram may be used to visualize adult worms within the heart or major vessels, particularly in advanced infections.

How Is Heartworm Disease Treated?

In most cases, heartworm disease is treatable, but early detection and proper staging are critical.

Before beginning treatment, our veterinarians perform chest X-rays, bloodwork, and urinalysis to determine the stage and severity of the disease. Once staging is complete, a customized treatment plan is developed.

Heartworm Treatment Steps:

A. Immiticide Injections – The primary treatment involves Immiticide, an injectable medication that kills adult worms. The typical protocol includes one injection followed by a month of rest, then two more injections given 24 hours apart.

B. Strict Rest – During treatment, strict rest is essential. As worms die, they break apart and can cause blockages (emboli) in the lungs if a dog is too active, which can be fatal.

C. Supportive Medications – Additional medications such as anti-inflammatories and antibiotics may be prescribed to reduce inflammation and control infection.

Because Immiticide is a strong medication, possible side effects include injection-site pain, coughing, fever, vomiting, or appetite loss. Serious complications—such as lung inflammation or sudden death—are rare but possible.

After treatment, a follow-up antigen test is performed 6–12 months later to confirm that the infection has cleared. In some cases, a second treatment round may be necessary. Dogs with very severe infections may require surgical removal of the worms by a veterinary cardiologist, though this is rare and carries a guarded prognosis.

How to Prevent Heartworm Disease

The best approach to heartworm disease is prevention. Preventive medications are safe, effective, and easy to use.

• Preventatives are given monthly (oral or topical) or as an injection every 6 or 12 months.

• All dogs over six months old must be tested for heartworms before starting prevention.

• These medications kill the immature larval stages of the parasite before they can develop into adult worms.

Even with consistent use, no prevention is 100% foolproof. For that reason, the American Heartworm Society recommends annual heartworm testing for all dogs. Missed doses, vomiting, or late administration can all put your dog at risk for infection.

Schedule a Heartworm Test or Prevention Appointment

Heartworm prevention is far easier—and far safer—than treatment.
At Lubbock Animal Medical Center, we provide comprehensive heartworm testing, prevention, and treatment options tailored to your dog’s health and lifestyle.

Call us at (806) 794-4118 or book your appointment online today to protect your dog from this preventable disease.