Which combination of symptoms is listed as early indicators of heartworm infection?

• A. Shortness of breath; pale gums; fevers.
• B. Vomiting; hair loss; itching.
• C. Shortness of breath; shallow cough; tendency towards tiring easily.
• D. Sneezing; nasal discharge; coughing.

Answer: (C)

Early indicators of heartworm infection come from how the worms affect the heart and lungs. In the early stage, you often see a mild, persistent cough and exercise intolerance because the worms in the pulmonary arteries cause inflammation and increased resistance to blood flow, making breathing harder during activity. That combination—shortness of breath, a shallow cough, and a tendency to tire easily—fits these early signs well.

Other symptom sets don’t align as closely with early heartworm. Vomiting, hair loss, and itching aren’t typical early indicators of heartworm infection, as they point more to gastrointestinal or skin issues. Sneezing, nasal discharge, and coughing suggest upper respiratory or allergen-related problems rather than early heartworm disease.