Heartworms are invasive parasites that can make your dog very ill and, if untreated, can kill him. Your dog can get infected with heartworm larvae through the bite of a mosquito that has bitten an infected dog. Once the larvae are in the bloodstream, they mature and grow into adult worms that clog your dog’s blood vessels, lungs and heart. This causes respiratory and circulatory issues and can cause organ damage. There are treatments to rid your dog of heartworms but they can be expensive, may require surgery, and may not bring your dog back to his former health. Fortunately, there are heartworm preventative medications available by prescription to protect your dog. Give your dog this monthly medication all year round since just a few warm days can cause mosquitoes to become active. Your dog will need periodic blood tests to ensure that he hasn’t inadvertently been infected with heartworms. Learn more from your Lakeville, MN veterinary clinic.