In dogs, roundworms are a very frequent parasite. Almost every dog has roundworms at some point in their lives, most commonly when they are dogs.
-Toxocara canis and Toxascaris leonine are the two main species of roundworms that infect dogs. Toxocara canis is a more dangerous parasite that can infect people.
-Toxocara canis, a canine roundworm, can grow to be several inches long.
Adult roundworms reside in the intestines of dogs, feeding on partially digested food. Malnourishment can be caused by the worms, which is especially dangerous in a young puppy. Roundworms are particularly dangerous to puppies and young dogs because their immune systems have not fully matured and they are unable to fight off adult worms as effectively as an adult dog.