Heartworm disease, caused by Dirofilaria immitis transmitted by mosquitoes, is a serious and potentially fatal condition in dogs that is entirely preventable with monthly medication.
Heartworm disease causes progressive and painful deterioration in cardiac and pulmonary function. Dogs with heavy worm burdens experience severe exercise intolerance and ultimately heart failure. Prevention is simple and cheap; treatment of established disease involves weeks of cage rest, injections and risk of pulmonary embolism.