Heartworm disease causes severe cardiopulmonary suffering in dogs. Monthly preventive medication eliminates this welfare risk almost entirely, making prevention the definitive welfare intervention.
Heartworm disease causes progressive cardiopulmonary suffering over months to years before clinical signs prompt veterinary attention. By the time a cough or exercise intolerance appears, hundreds of worms may already occupy the pulmonary vasculature. The treatment itself — restricted activity for weeks and potentially serious pulmonary embolism as dying worms are cleared — adds iatrogenic welfare cost to the disease burden. Monthly prevention is so effective and so simple that heartworm disease in a dog on consistent prevention is essentially eliminated. The welfare case for year-round prevention in endemic areas is unambiguous. Owner compliance is the primary barrier — medication reminders, annual testing, and veterinary relationship maintenance all improve compliance and welfare outcomes.