Heartworm disease causes severe and progressive suffering in dogs, but is almost entirely preventable through widely available and safe monthly preventive medications, making prevention a fundamental welfare obligation.
Heartworm disease represents a welfare harm that is almost entirely preventable with consistent use of safe, affordable monthly medications. Dogs with established heartworm infection experience progressive cardiopulmonary disease that worsens over months to years, causing increasing exercise intolerance, respiratory distress, and eventual heart failure. The suffering associated with advanced heartworm disease is significant and prolonged. Treatment is available but involves weeks of strict cage rest, multiple veterinary procedures, and risks from the dying worms themselves. Monthly heartworm preventives administered year-round, or at least during mosquito season in temperate regions, provide highly effective protection against infection. The welfare calculus strongly favors prevention: safe, low-cost monthly medication versus potentially fatal disease requiring intensive treatment or causing chronic suffering.