Heartworm disease is a serious, potentially fatal parasitic infection in dogs that is expanding geographically as climate change alters mosquito ranges.
Heartworm disease causes progressive, severely debilitating illness — chronic cough, exercise intolerance, fainting and ultimately heart failure. Preventive medication is so effective and affordable that any heartworm infection in a pet dog represents a preventive failure. Treatment of established infection is painful, requires strict exercise restriction for months and carries real risk of complications from dying worms. As mosquito vectors expand due to climate change, previously low-risk regions are becoming endemic. Year-round prevention is increasingly recommended even in temperate climates.