Dogs and cats that do not receive monthly heartworm prevention are at increased risk. Dogs and cats may be heartworm infested and not show clinical signs. In dogs the most common clinical signs include coughing, exercise intolerance, acute respiratory distress and collapse. Cats are less likely to show clinical signs, but when they do, coughing, difficulty breathing, vomiting and lethargy are commonly observed.
Dr. Leo Londono D.V.M.- HAH
University of Florida