While parasites are a common occurrence in dogs, they can be quite unpleasant (or even deadly) depending on the type. If left untreated, dog parasites can multiply, wreaking havoc on your dog's system. Parasites can live in any number of places within your dog's body. Most parasites live in a dog's intestines, while others can be found in a dog's heart and in the blood vessels that lead from the heart to the lungs. Other susceptible areas include your dog's coat and ears. Learn more about the different types of dog parasites, what organs are affected, symptoms to look for, best prevention tips and some of the most effective treatment options.