Dogs can develop persistent cough, runny nose, fever and nasal discharge from the virus, and some have died. (tampabayvets.net)
Early signs of heartworms in dogs: a mild persistent cough, reluctance to exercise, fatigue after moderate activity, decreased appetite, and weight loss. (animalleaguewellness.org)
They can cause persistent coughing symptoms, loss of fever and appetite, though most dogs recover without medical intervention. (vetinfo.com)