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My dog might have heartworm. What symptoms should I look for?

Updated on September 23rd, 2025

Pet's info: Cat | York Chocolate | Female | spayed | 1 year and 4 months old | 13 lbs

what are the symptoms of heart warms in a dog?

3 Answers

Most Helpful Answer

Answered By Sarah Derksen, DVM

Veterinarian

Published on February 17th, 2018

Hi. I sure hope Mason doesn't have heartworm disease. In the early stages of heartworm infection, dogs show few symptoms or no symptoms at all. The longer the infection persists, the more likely symptoms will develop. More active dogs, dogs heavily infected with heartworms, or those with other health problems often show pronounced clinical signs.

Signs of heartworm disease may include a mild persistent cough, reluctance to exercise, fatigue, appetite changes, and weight loss. As heartworm disease progresses, pets may develop heart failure and the appearance of a swollen belly due to excess fluid in the abdomen. Dogs with large numbers of heartworms can develop a sudden blockages of blood flow within the heart leading to a life-threatening form of cardiovascular failure showing labored breathing, pale gums, and dark bloody or coffee grain like material in urine.

If you are worried about Mason possibly having Heartworm disease, please schedule an appointment and testing with your veterinarian.

1Pet Parents found this answer helpful

Related Answers from Veterinarians

Answered By Dr. B. DVM, DACVIM (Oncology)
Veterinarian
Published on June 25th, 2018
This is such a great question as this disease is so common in some areas of the country. The signs can be varied dependent on how advanced the process is in the individual pet but the most common symptom that owners note is coughing. Dogs may also act more tired, be less interested in going on walks, have weight loss/decreased appetite, and in more severe causes may have discolored (rust) colored urine or collapse. The American Heartworm Society has a great website, www.heartwormsociety.org. I hope this information is helpful and thanks for using Petcoach.
2Pet Parents found this answer helpful
Answered By Dr. Massimo Orioles, DVM, Cert AVP, MRCVS
Veterinarian
Published on December 28th, 2016
Heart signs (lethargy, labour breathing, heart murmurs at physical examination) respiratory signs (dyspnoea, coughing, raspy breathing) and chronic vomiting could be main signs of this infestation.
Only certain kind of medications against worms can prevent and treat heartworms. If unsure discuss with your veterinarian the most appropriate one (it is on prescription).
1Pet Parents found this answer helpful

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