Gross!! Hookworms are the most common parasite that are found in the intestinal tract of puppies and kittens. How do they get this? This parasite can be transmitted to an unborn puppy or kitten from their mother, from pet to pet or directly from the environment. So please, when walking your dogs make sure you're picking up their stool to limit the risk of other dogs contracting them. Also make sure you wash your hands thoroughly, you don't want parasites either! Hookworm if left untreated can cause severe anemia.