Which of the following is a symptom of heartworm infection in pets?

Chronic cough is a symptom of heartworm infection in pets primarily due to the presence of adult heartworms in the pulmonary arteries, which can lead to inflammation and respiratory issues. As heartworms mature, they can cause significant damage to the heart and blood vessels, resulting in symptoms that affect the respiratory system. A chronic cough is often one of the earliest signs that a pet may be suffering from heartworm disease, as the worms irritate the lungs and airways, leading to prolonged coughing fits.

The other options do not directly correlate with heartworm infection. Excessive barking may indicate behavioral issues rather than a physical ailment, while frequent urination is more commonly associated with urinary tract issues or diabetes. Skin irritation is typically linked to allergies or external parasites rather than heartworms. Understanding the specific symptoms associated with heartworm infection is crucial for timely diagnosis and treatment.