The Four Most Common Worms in Pets

If your dog or cat has worms, chances are, it’s one of these four:

  • Tapeworms: an intestinal parasite that is transmitted by ingesting fleas or wildlife that is infested with fleas. Apparently fleas think tapeworm eggs are a real treat. (I don’t see the allure, personally.) The biggest clue that your pet has tapeworms is seeing worm segments in the feces or in the fur near the tail. The little segments look like grains of rice or sesame seeds. An entire tapeworm can have as many as ninety segments and reach six inches in length; the segments that you see outside the pet usually contain eggs.
  • Roundworms: puppies and kittens can be born with roundworm larvae that migrate into the mother’s uterus and into the babies. The larvae grow into adults in the intestinal tract, then start to lay eggs. Eggs may be passed in the stool; those that hatch can migrate into the lungs. In adult dogs, the larvae can encyst in body tissue and lay dormant for a long time. A puppy or kitten with a roundworm infestation may have a pot-bellied appearance and will often grow more slowly than non-infested animals. Worms can often be seen in vomit and/or stool.
  • Hookworms: small, thin worms that “hook” into the walls of the intestines to suck blood. These worms are more often seen in dogs than in cats, but can appear in both. Like roundworms, a pet can get hookworms from larval migration in the uterus. They can also get hookworms from contact with contaminated soil and infested stool. A severe infestation can be fatal to puppies and kittens. These worms cannot be seen without a microscope; symptoms of infestation include bloody diarrhea, weight loss, and progressive weakness.
  • Whipworms: another parasite more often seen in dogs than in cats. These are long, threadlike worms that live in the first section of the large intestine. Whipworms cannot be seen without a microscope. Symptoms of infestation include chronic weight loss and stool that seems to be covered with mucus.