Heartworm infection is a condition caused by the presence of heartworm larvae (Dirofilaria immitis) in an animal's bloodstream. These parasites are transmitted to animals through the bite of infected mosquitoes, and they eventually make their way to the heart where they grow into adult worms. Heartworm infection can cause severe damage to the heart and lungs, leading to a range of health problems for affected animals. In dogs, it is also known as "Adult Dirofilariasis."