Heartworm disease is a serious and potentially fatal parasitic infection in dogs. Prevention is simple and effective; treatment is complex, expensive, and burdensome on affected dogs.
Heartworm disease welfare involves both the chronic suffering of infected dogs and the acute burden of treatment. The disease progression causes gradual cardiovascular compromise — reduced exercise tolerance, coughing, and fatigue that many owners attribute to aging rather than disease. By the time dogs show clinical signs, significant permanent damage has often occurred. Treatment itself causes significant welfare impact: the immiticide injections cause muscle pain and soreness, and the required exercise restriction for months is genuinely difficult for active dogs and stressful for owners to enforce. The welfare case for prevention is overwhelming — monthly preventatives prevent all of this suffering at minimal cost and burden. Access to affordable prevention is an equity issue that affects dogs in lower-income households disproportionately.