6 Signs of Heartworm in Dogs

What are the signs of heartworm in dogs? Heartworm disease often causes symptoms such as coughing, lethargy, breathing difficulties, bloat, and weight changes, and it can become life-threatening if left untreated. Heartworms are parasites spread through the bite of an infected mosquito, and they commonly affect puppies and shelter dogs. Early recognition of symptoms is critical for protecting your dog’s health.

At Parkway Veterinary Emergency Clinic in Lakeland, FL, we help pet owners recognize serious symptoms like heartworm disease and provide urgent care when needed.

1. Persistent Loud Cough

What are the first signs of heartworms in dogs? One of the most common signs of heartworm in dogs is a persistent, dry, and loud cough. While an occasional cough may not be concerning, a cough that worsens or continues over time should be evaluated by a veterinarian.

Heartworms can travel through a dog’s body and lodge in the lungs, creating blockages that make breathing difficult. This irritation often leads to a distinctive dry cough that sounds different from typical coughing.

2. Lethargy

Lethargy is another common symptom of heartworm disease. Dogs may lose interest in walking, playing, or eating. Because lethargy can be associated with many conditions, it is important to seek veterinary care as soon as it is noticed.

As lethargy progresses, dogs may become increasingly inactive, which can lead to obesity and additional health complications.

3. Weight Loss or Weight Gain

Dogs with heartworms may experience unexplained weight changes. Some dogs gain weight due to inactivity caused by lethargy, while others lose weight because of a decreased appetite.

Weight loss can be especially concerning, as it may result in dehydration and the loss of essential vitamins and minerals needed for normal bodily function.

4. Increased Difficulty Breathing

Difficulty breathing is a serious sign of heartworm disease and may occur with or without coughing. As heartworms migrate to the lungs, they interfere with normal airflow.

Fluid may also accumulate in the lungs and blood vessels, limiting oxygen intake. Dogs showing signs of labored breathing should be seen immediately, as this can quickly become life-threatening.

5. Bloated Belly

A bloated abdomen is more commonly seen in puppies but can occur in dogs of any age with heartworm disease. This bloating is caused by fluid buildup and is not related to diet.

As fluid continues to accumulate in the body, the condition can worsen rapidly and may lead to death if not treated promptly.

6. Unexplained Fainting Spells

Sudden fainting or collapse is a sign of advanced heartworm disease and requires immediate veterinary attention. This occurs when heartworms have multiplied and caused significant damage.

At this stage, fluid buildup can obstruct blood vessels, reducing blood flow and oxygen delivery. Unexplained fainting is a medical emergency.

How to Treat Heartworms in Dogs

The only way to confirm heartworm disease is through veterinary testing. At Parkway Veterinary Emergency Clinic in Lakeland, FL, diagnosis is typically made using a blood test that detects heartworm proteins.

This test requires only a small blood sample and is quick and minimally invasive. Because heartworms take approximately six months to mature, dogs may test positive before showing visible symptoms. Puppies as young as six months old are often placed on preventative medication.

Keep Your Dog Up to Date on Heartworm Prevention

Dogs depend on their owners to recognize changes in behavior and health. Heartworm disease can progress silently and become fatal if left untreated.

If you notice coughing, lethargy, breathing issues, or fainting, contact Parkway Veterinary Emergency Clinic in Lakeland, FL at (863) 665-3199. Early detection and prevention are the most effective ways to protect your dog from heartworm disease and its serious complications.