Heartworm disease is a potentially fatal parasitic condition in dogs that causes severe cardiovascular and pulmonary damage, and prevention is far more welfare-protective than treatment.
Heartworm disease causes progressive, debilitating suffering. As worm burdens increase, dogs experience exercise intolerance, coughing, and eventual cardiovascular failure. Treatment — while often successful — involves months of strict confinement and the risk of pulmonary embolism from dead worms. Prevention with monthly medication is straightforward, affordable, and eliminates this entire welfare burden. In endemic regions, failure to provide preventative treatment represents a preventable welfare failure. Year-round prevention should be standard practice wherever heartworm transmission occurs.