Tapeworms and roundworms are internal parasites that commonly infect dogs. These parasites can drain nutrients from your pet and affect your dog's health in many ways. Signs you look out for are malnutrition and anemia. Some other warning signs in canines will be a swollen potbelly. In puppies you will notice their coat becoming dry and dull. It's good to have your pet tested by your Veterinarian and keep them on monthly preventive medicine. Ringworms are not a worm, but a fungus. A ringworm infection can be treated with topical antifungal creams or shampoos.