Dog Heartworm Prevention Welfare

Heartworm disease causes severe cardiopulmonary damage and is fatal without treatment. Prevention through monthly medication is inexpensive, safe, and far superior to treating established infection.

Key Facts

Heartworm (Dirofilaria immitis) is transmitted by mosquitoes and infects dogs across the Americas, Europe, and beyond
Adult worms live in the heart and pulmonary arteries, causing chronic damage over their 5-7 year lifespan
Treatment of established heartworm is expensive, risky, and requires prolonged restricted exercise
Monthly preventive medications including ivermectin and milbemycin are highly effective when given consistently
Climate change is expanding the geographic range of the mosquito vectors that transmit heartworm

Welfare Considerations

Dogs with established heartworm infection experience progressive cardiopulmonary disease including exercise intolerance, coughing, and eventually heart failure. Treatment requires weeks of restricted activity during which adult worms die and are reabsorbed - a period of discomfort and confinement that is stressful for active dogs. Prevention eliminates this suffering entirely through safe, inexpensive monthly medication. The welfare case for prevention over treatment is overwhelming: preventing heartworm costs a fraction of treating it and spares dogs months of suffering and the risks of adulticide treatment.

What You Can Do

Administer monthly heartworm preventive to all dogs year-round or seasonally as directed by your vet
Test dogs annually for heartworm before continuing preventives - resistance and compliance failures require detection
Support low-cost heartworm prevention programs in underserved communities where treatment rates are higher
Advocate for heartworm prevention education in regions where the disease is expanding due to climate change