Heartworm is a disease that arises through parasitic infestation of Dirofilaria immitis. The dog is the primary host although it can infect cats too and under very rare circumstances even humans. The disease is spread from host to host through the bite of infected mosquitoes. The heartworm inhabits the pulmonary arterial system and the heart of its host. Health problems that arise include damage to the lung vessels and tissues. In serious infections death typically results from congestive heart failure. While dogs all over the United States may become infected with heartworm the risk for infection is higher within 150 miles of the coast from Texas to New Jersey and along the Mississippi River. Many dogs show little to no signs of infection even after the worms become adults. For the first six months of infection, called the prepatent period, the worms are not adults and current diagnostic tests will not be able to detect their presence. Rare symptoms include blindness, seizures, and lameness in the event that a migrating heartworm ends up in the eye, brain or artery in the leg. Sometimes more active dogs will develop a cough. In cases of advanced infection the heartworms will have infested the heart and the animal might exhibits signs of severe weight loss, fainting, coughing up blood, and congestive heart failure finally resulting in death. DV Medical Supply advises clients to encourage preventative treatment among patients.