Roundworms, also known as ascarids, are the most common type of parasite seen in dogs, cats, puppies and kittens. Roundworms have been known to infect people, particularly children.
Parvovirus, or parvo, infection in dogs is often a fatal disease. It is caused by a virus, called a parvovirus, which infects the intestinal system of dogs and is especially dangerous for young puppies.