How to Tell If My Dog Has Heartworms

Learn how to tell if my dog has heartworms. The canine heartworm is a disease of dogs that can become serious and fatal if not detected and treated early.

Although its name suggests cardiac symptoms, heart failure only occurs in advanced cases, and is essentially a pulmonary disease, since the location of adult worms is the pulmonary arteries.

It must be considered that it is a pathology of chronic evolution; Dogs can remain asymptomatic for months or years, depending on the parasite load, individual susceptibility, and level of daily exercise – arterial damage is usually more severe if the animal engages in vigorous exercise.

how to tell if my dog has heartworms

How to Tell If My Dog Has Heartworms – Symptoms

The clinical signs of heartworm develop gradually and are caused by invasion of the pulmonary arteries and the right ventricle by adult worms.

It is true that some symptoms can be seen in other cardiopulmonary diseases, such as pneumonia or heart failure, but heartworm infestation should be included in the differential diagnosis, especially in endemic geographic areas.

The initial symptoms that the pet presents with heartworm disease are:

  • Cough chronic.
  • Moderate to severe dyspnea (shortness of breath).
  • Syncope after exercise or excitement.

Advanced symptoms in dog heartworm problem consists of:

  • Signs that look like congestive heart failure: ascites, vascular edema, dehydration, anorexia, weight loss
  • Heart murmurs and arrhythmias (atrioventricular fibrillation).                
  • Thromboembolism due to worm death that causes dyspnea and hemoptysis.
  • Pulmonary hypertension (vena cava syndrome) during the migration of worms from the pulmonary artery to the right ventricle, which generates dyspnea, murmurs, hemolysis, hemoglobinuria (dark urine) and death.
  • Death from severe respiratory failure or progressive emaciation (pathological weight loss).
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How to Detect Heartworms in Your Dog?

Dogs with heartworms can remain asymptomatic for a long time, but during this period, circulating microfilariae in the blood or adult heartworm antigens can be detected.

That enables effective treatment to be started as soon as possible. The diagnosis of canine heartworm disease is made by:

  • Direct observation of microfilariae: A blood sample is taken, and a blood smear is made to directly observe the microfilariae under the microscope. Previously, microfilariae can be filtered or concentrated to detect them more easily. A negative result does not rule out infection, since 30% of dogs infected with adult worms do not have microfilariae. Therefore, it must be complemented with other laboratory techniques.
  • Detection of heartworm antigens: using ELISA or immunochromatographic tests (rapid tests), the presence of adult heartworms can be detected in blood. The result may be negative if the incubation period has not been completed (6-8 months after infection).
  • Imaging: In the advanced stages of the disease, changes in the lungs and heart can be seen by radiography. Cardiac arrhythmias are detected by electrocardiography. Abnormalities within the heart, and even adult worms, can be visualized by echocardiography.

Now that you know my secret on how to tell if my dog has heartworms, take the first step and make sure your dogs stay healthy every day!

Important: This article is for informational purposes only. We always recommend that you go to a trusted vet with your pet first.