Heartworm disease causes severe pulmonary and cardiac damage in dogs, with treatment requiring strict rest protocols that are stressful for active dogs but essential to prevent fatal complications.
Both the disease and its treatment create significant welfare burdens. Heartworm disease causes chronic respiratory compromise with exercise intolerance that progressively worsens over years. Treatment kills adult worms but creates a period of heightened risk - dead worm fragments can block pulmonary vessels, making any exercise potentially fatal during the 8-12 week rest period. Restricting an otherwise healthy, active dog to near-complete rest is psychologically challenging for the animal. Prevention through monthly medications eliminates both the disease burden and the treatment ordeal entirely.