Heartworm disease causes severe cardiopulmonary suffering in infected dogs, and monthly preventive medication is far more effective and welfare-friendly than treating established infection.
Heartworm disease imposes a prolonged and serious welfare burden on affected dogs. Clinical signs including exercise intolerance, coughing, and right heart failure develop slowly over years but cause progressive suffering. Treatment itself carries significant welfare costs including painful injections, months of strict confinement, and risk of life-threatening pulmonary thromboembolism. The contrast between the safety and simplicity of prevention and the severity of treatment makes this one of the clearest cases in veterinary medicine where prevention is the overwhelming welfare choice.