Pet Health Library – Marin Pet Hospital, San Rafael, CA

Internal Parasites

Most internal parasites are worms and single-celled organisms that
can exist in the intestines of dogs or cats. The most common worms
are roundworms, hookworms, whipworms and tapeworms. Common
single-cell parasites are coccidia and Giardia.
What are roundworms and how are they spread?
Roundworms are the most common intestinal parasite in dogs and
cats in the world. Animals with roundworms pass the infection to
other animals when the worm eggs develop into larvae and are
present in the animal’s feces (droppings). Your pet can pick up the
infection by eating infected soil, licking contaminated fur or paws,
or by drinking contaminated water.