Heartworm disease causes progressive cardiopulmonary suffering preventable through monthly or annual chemoprophylaxis, with prevention welfare-superior to treatment of established infection.
Heartworm prevention is a paradigmatic welfare case where monthly administration of a low-dose, low-risk medication prevents years of progressive suffering from an otherwise devastating disease. The welfare hierarchy is clear: prevention has minimal welfare cost; treatment involves significant welfare burden from exercise restriction and thromboembolic complications; untreated advanced disease causes sustained cardiopulmonary suffering that meaningfully impairs quality of life. The expanding geographic range of heartworm disease with climate change means that dogs previously considered safe from risk now require preventive attention. Welfare-centered pet ownership treats heartworm prevention as a routine healthcare obligation, not an optional expense.