Canine Heartworm

DISEASE INFORMATION

What are the signs of canine heartworm?

Domestic dogs may have a chronic cough, low stamina, or respiratory distress when infected. Heavy infestations may lead to heart failure.

Heavy infestations can result in worms blocking and irritating the pulmonary artery; this causes subsequent enlargement of the right side of the heart and decreased lung efficiency. Congestive heart failure may occur, leading to lung, liver​ and kidney damage.

How is canine heartworm diagnosed?

On necropsy, diagnosis is by recovery of adult worms from the heart. In live animals, diagnosis is through an x-ray or a blood test; microfilariae (tiny worms) can be seen in a blood sample once the infestation is heavy enough.

What is the significance for wildlife management?

Coyotes can be stressed by heartworm infestation and occasional mortality occurs; however, population-level effects are unlikely because infected coyotes are largely asymptomatic. Foxes and bears are also very uncommon hosts of the disease. Based on the best information available, the most probable infection source for domestic dogs is other dogs, and not coyotes.

How is canine heartworm treated?

Giving your dog heartworm prevention is the best method for control of the disease. Once an animal has been diagnosed with canine heartworm, treatment is available but is both costly and potentially dangerous. There is no control or treatment feasible to use on wildlife.

Does canine heartworm pose a risk to people or other animals?

Occasionally, people have been diagnosed with a single heartworm in the lung. However, it is rarely found in the heart in humans. It does not generally cause disease symptoms in people, and its occurrence is such a rare event that it is not a major public health concern.

In terms of other animals, canine heartworm can affect domestic dogs, as well as coyotes, red and gray foxes, and black bears.​​​