Intestinal Parasites – the Scoop on Poop!

By Sharon Billings, CVT
Associate Veterinary Information Specialist

Dog Close UpSo, you and your beloved four-legged family member are on your way to the veterinary clinic for a routine check-up and you have the requested fecal, or stool, sample along for the ride.  You’ve collected a sample and triple-bagged it; you’re glad your part of the task is over but you’re wondering:  why do they need the smelly little package?  What do they do with it, anyway? In today’s blog, we’ll explore intestinal parasites and give you the scoop . . . on poop.

What We Look For And How We Do It:

The goal of a fecal test is to detect the presence of intestinal parasites in order to prevent illness and further transmission.  The most common intestinal parasites affecting companion animals such as cats and dogs are two protozoan parasites, coccidia and giardia, and worms such as hookworms, roundworms, tapeworms, and whipworms.

The small sample you bring with you is typically processed and examined by a veterinary technician, either on-site at the clinic or at an off-site testing lab.  The sample may be processed via several different methods to separate the fecal matter from the stuff of interest — protozoan organisms and worm eggs — so they can be seen and identified with the aid of a microscope.

Why Intestinal Parasites Are So Common:

Adult intestinal parasites spend their entire lives inside a host (your dog or cat) and depend on the host for food and an environment in which to reproduce.  To continue to reproduce, the parasites’ offspring must migrate from one host to other hosts — and they are very good at this!

Intestinal parasites are so common because they can be transmitted in a wide variety of ways.  For example:  your pet sniffs / comes in contact with an infected animal’s feces or drinks from contaminated water (pond or puddle) or ingests an infected small animal or even an infected flea or cockroach.  In some instances intestinal parasite worm larvae can even penetrate through skin when your dog or cat walks across contaminated soil.  In some cases, the worm larvae are capable of hypobiosis — they can “lie low” in the host’s body in a state of arrested development and then become active again when conditions are right for them to be passed from a mother dog or cat to a fetus before birth or through her milk after birth.  So, it’s considered a “given” that puppies and kittens are born with intestinal parasites.

Why Intestinal Parasite Testing and Control / Treatment Are Important:

By definition, parasites live off their hosts.  In some cases, adult worms feed off the blood of the host.  If the parasite burden for a host is small, there may be no outward signs or significant health impact to the host.  But very young, very old, or otherwise at-risk pets may be more severely affected.

Outward signs you may see include a pot-bellied appearance, vomiting, diarrhea, blood in vomit or stools, adult worms in vomit or stools.  Additionally, symptoms may include weight loss / failure to thrive, dull hair coat, and pale gum color.  In severe cases, adult worms ingest so much of the host’s blood that a puppy may die from anemia.

Perhaps you’re wondering, if you have a healthy adult pet who is unlikely to suffer significant effects from a parasitic invasion, why is testing and control so important?  The parasites are easily passed along to other animals who may be more vulnerable.  And then there’s zoonosis.  A zoonotic disease is one that can be passed to humans.  You may acquire some of these intestinal parasites from your pet by contact with contaminated feces or soil.  So, let’s say your healthy adult dog, who is harboring intestinal parasitic worms, defecates in your yard in which you walk barefooted.  That’s all it takes.  The larvae contaminate the soil and can actually penetrate through your skin, enter your bloodstream and travel to other parts of your body – including inside your EYES!  This is called ocular larval migration.

How Intestinal Parasites are Controlled / Treated: 

This all brings us back to that fecal sample you are bringing with you to your veterinarian appointment.  Your veterinarian most likely has recommendations for periodic fecal testing for cats and dogs, usually once or twice a year for healthy adults but more frequent for new arrivals (puppies and kittens).  The test will ensure there is no infestation that needs to be addressed.  And if there is evidence of a parasite your veterinarian will provide treatment, usually in the form of a medication given by mouth.  Your veterinarian may recommend your cat or dog be placed on a regular monthly or quarterly oral medication program to help prevent infestation.

In addition, there are some simple common-sense steps you can take to help prevent the spread of intestinal parasites:

  • Keep sandboxes covered when not in use and protect garden areas from fecal contamination.
  • When walking your dog in public, collect feces immediately.
  • At home, collect feces from your yard on a daily basis.
  • Avoid handling feces with bare hands and wash hands immediately if any dermal contact should occur.
  • Dispose of waste according to your local municipal regulations.

The Companion Animal Parasite Council has lots of information on a website especially designed for pet owners.  Visit them at: