12 Signs & Symptoms Of Heartworm Disease In Your Dog


Heartworm disease in dogs is a serious and potentially fatal condition caused by parasitic worms called Dirofilaria immitis. These worms are transmitted through the bite of an infected mosquito. The signs and symptoms of heartworm disease in dogs can vary depending on the stage of the disease and the number of worms present in the dog’s body. Some common signs and symptoms include:



A persistent dry cough is one of the most common signs, which may become more noticeable after exercise and can be mistaken for a kennel cough or other respiratory infection.


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Dogs with heartworms may become easily tired and may show reluctance to engage in activities they once enjoyed.

Weight Loss


As the disease progresses, dogs may experience weight loss and loss of appetite.

Difficulty Breathing


As the worms occupy space within the heart and lungs, breathing can become more labored, especially during and after exercise.

Swollen Abdomen

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Fluid can accumulate in the abdomen due to poor blood flow, causing a swollen belly, a condition known as ascites.

Heart Murmurs

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Veterinarians may detect heart murmurs or changes in heart sounds due to the disruption of normal blood flow.



In severe cases, a dog might collapse due to the heavy worm burden affecting the heart’s function.

Exercise Intolerance


Dogs with heartworm disease often have decreased stamina and may become winded or weak with minimal exertion.



Less commonly, dogs may experience nosebleeds as a result of the disease.

Dark Urine


In advanced cases, the urine may become dark due to the breakdown of red blood cells.


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If the disease leads to liver damage, you might notice yellowing of the gums, skin, or whites of the eyes.

Sudden Death


Unfortunately, in some cases, the first sign of heartworm disease may be sudden death, especially if the worm burden is high and causes a blockage of blood flow (caval syndrome).

It is important to note that in the early stages of heartworm disease, dogs may not show any signs or symptoms at all. This is why regular screening and preventive measures are crucial. A veterinarian can perform a blood test to check for heartworms. If a dog tests positive, further tests such as chest


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