Catching Heartworm Early: The Hidden Danger You Can’t See

Heartworm disease often works quietly in the background with no visible signs until it's already threatening your pet’s heart and lungs. That’s what makes it so dangerous and why early detection is so critical. At Animal Medical Center of Kansas City, we’ve seen how routine testing catches infections long before symptoms show up, giving pets the best chance at recovery. If you think your pet “seems fine,” this warning for National Heartworm Awareness Month is especially for you.

The Stealthy Nature of Heartworm Disease

Once a mosquito carrying heartworm larva bites your pet, those microscopic invaders enter the bloodstream and begin migrating to the heart and nearby blood vessels. Over time, they mature into adult worms. Some heartworms can reach up to a foot long. The problem? This entire process can take six months or more, and during that time, your pet might not show a single symptom. That’s why heartworm is often called a “silent killer”—by the time signs appear, serious damage has likely already occurred.

Heartworm Symptoms Don’t Always Show Up Early

In the early stages, your pet may look and act perfectly healthy. But beneath the surface, those growing worms are causing inflammation and straining your pet’s circulatory system. When symptoms of heartworm disease do appear, they can include:

• Coughing or wheezing
• Lethargy or exercise intolerance
• Labored breathing
• Weight loss
• Sudden collapse or death (especially in cats)

Catching heartworms before these signs develop is key to preventing irreversible harm. Delaying testing or skipping it entirely can lead to harder-to-treat infections, more expensive and lengthy treatment processes, and permanent damage to your pet’s heart or lungs. And in cats, where no approved treatment for adult heartworms exists, early detection could mean the difference between life and death.

How Routine Heartworm Testing Saves Lives

A standard heartworm test for dogs is a quick, low-stress part of your pet’s annual checkup. A small blood sample is collected. The test checks for antigens from adult female heartworms. Results are typically available in just a few minutes. If the test is positive, further diagnostics like X-rays or ultrasounds may be recommended to assess the extent of the disease and determine the safest treatment plan. Testing for early heartworm disease in cats is a bit trickier, so talk to your veterinarian for their recommendations.

Many pet owners ask, “If my pet is on heartworm prevention, do they still need to be tested?” The answer is yes.

• No medication is 100% perfect.
• Pets may spit out pills or vomit without you noticing.
• Rare drug resistance or improper dosing can lead to infection.
• Early-stage infections can go undetected without testing.

Your veterinarian can discuss heartworm prevention and testing with you during your pet’s yearly wellness exam.

Get a Heartworm Test for Your Pet with Animal Medical Center of Kansas City

Heartworm disease rarely announces itself, but testing shines a light on what you can’t see. When combined with year-round prevention, an annual heartworm screening is one of the most powerful tools you have to keep your pet healthy. At Animal Medical Center of Kansas City, we make it easy to test, treat early if needed, and stay ahead of the threat. Don’t wait for heartworm disease symptoms to appear. If you have a pet in Kansas City or nearby areas like Waldo or Brookside, book an appointment for your pet’s annual heartworm test and stay one step ahead of this silent threat.