Heartworm disease is a potentially fatal parasitic infection of dogs transmitted by mosquitoes. Prevention is highly effective and profoundly preferable to treatment, both for welfare and cost reasons.
Heartworm disease represents a welfare problem with a highly effective preventive solution that is not universally applied, primarily due to cost, owner awareness gaps, and variable veterinary communication about risk. Dogs with established heartworm infection experience months of chronic cardiovascular compromise, often presenting with advanced disease because early signs are subtle. Treatment itself involves a period of welfare compromise — strict exercise restriction, discomfort from injections, and risk of pulmonary thromboembolism as worms die. The welfare calculus strongly favours prevention: monthly medication is safe, highly effective, and eliminates the welfare burden of infection entirely. Expanding access to preventive medication for dogs in lower-income households or in high-endemicity regions is a direct welfare intervention.