That bunny ain't dropping Easter eggs

Years ago, pregnant with my first child and having no veterinary training yet, I acquired a young Nubian goat kid with diarrhea. Fecal testing revealed a protozoan parasite referred to generically as coccidia. A cautious expectant mother, I asked my physician if exposure to goat coccidia was harmful to my unborn baby. When he reported back that goat coccidia (Eimeria spp.) are "host specific" -- meaning goat Eimeria are contagious only to other goats -- I was very relieved.


Flash forward a decade and I find myself, now an animal doctor, doling out this same information to dog owners on a regular basis. Finding microscopic coccidia eggs on an annual fecal float test is not uncommon. Dogs may pass Isospora or Eimeria eggs in their stool, but as with goats these coccidia parasites are "host specific." As I explain this to horrified pet owners, they are relieved to hear it is not contagious to them or their children.

A small sampling of the oodles of eggs
-- coccidia, not Easter -- being passed by two
sick bunnies I saw this month. 

Identifying the presence of coccidia is easy. Now here's where it gets tricky. Remember that coccidia are "host specific." If a dog tests positive for an Isospora-type coccidia it may require treatment because Isospora is a dog coccidia. But if an Eimeria-type coccidia is seen, the dog is simply pooping out the coccidia that a rabbit once pooped out. Quickly differentiating between Isospora from Eimeria based on subtle differences in size or ornamentation takes practice and experience. Nevertheless, seeing as nibbling rabbit poop is a pretty common canine past time, chances are pretty good that many dogs are pooping out a non-canine coccidia.*

Many animals host coccidia without any outward signs of illness. In fact, sickness generally occurs only in very young animals during times of stress. As in my goat kid, coccidiosis may cause severe diarrhea. My yellow Labrador developed screaming diarrhea a few days after we brought him home as a puppy thanks not only to Isospora spp. but also to the stress of leaving his litter. Some of my canine patients--puppy or adult--that test positive for coccidia have unexplained scooting or butt licking without abnormal stools. A short course of treatment for coccidia often relieves all these symptoms.

I recently examined two very young bunnies with diarrhea and lack of appetite. These baby bunnies had been turning up their twitching little noses at hay and pellets for several days, eating nothing but carrots (a treat, not a balanced meal). The day I examined them they had been passing liquid orange stool for several hours. Not having had an occasion to test a pet rabbit's stool before, I was unsure of what I would find. Imagine my surprise when I focused my microscope on the fecal float slide to find hundreds of oval eggs. Coccidia! Eimeria-type no doubt. Treatment with anti-coccidia medication--a teeny tiny portion of the average dog dose--was started immediately, and the owner decided to provide additional nursing care at home.

What fascinates me about this case is not so much identifying rabbit coccidia -- as I explained, we veterinarians see it all the time as an incidental finding on canine fecal floats. It's just that I had never seen so much of it in one place. And never had I paused to think about what the rabbit coccidia might do to the rabbit! The story of these two very sick baby bunnies overwhelmed by coccidia has given this parasite a face and personal meaning to me.


* Cats can be infected with or shed coccidia in their stool as well including various species of Isospora or Eimeria which are not contagious to people. 

Your Pet Pooped on the Floor: Why Your Vet Can't Assume It's Behavioral

Here's the scenario. A family adopts two "teenaged" spayed female cats from the shelter. These two teeny boppers are welcomed into the household by the older neutered male cat and the family's dog. The introduction appears seamless. The new kitties cuddle with the labrador and cavort with the cat. But someone has pooped on the couch! And the rug! The owners know it's one of the cats but which one? Is it Mister, latently unhappy about sharing his digs? Is it one of the new kitties, unsure of her surroundings or just reveling in her new freedom to go where she pleases? The poops are pretty normal looking, so it seems like a behavioral issue.


As the family's veterinarian, my first response is "we gotta get a stool sample and run some tests." The only way to diagnose a behavioral toileting problem is to rule out medical causes first.  


"But how will we know whose poop is whose?"

Sometimes that matters and sometimes it doesn't. I like to run the fecal tests on the aberrant stool...one that's softer or yuckier than most or the one that's been deposited where it doesn't belong. The owner of the stool-- when we're talking cats--usually doesn't matter if the problem is infectious or parasitic. Because cats generally share litter boxes we assume that if one of them has worms (for example) they all have worms and all need to be treated accordingly.

Before long I was in possession a fresh sample from one of the new kitties. When evaluating a stool sample for abnormalities, the first test is simple observation. Yes, it's gross, but what does it look like? How does it smell? Sometimes we'll probe the sample with a be-gloved hand checking for foreign material or worms, but 3 out of 5 senses is as far as it goes! This sample happened to be soft but formed with a portion being slightly runny. 

In my veterinary practice a complete fecal test includes a smear, a float and a Giardia "snap" test. These in-house tests identify the most common causes of inappropriate defecation and outright diarrhea.

The fecal float is the test most well known. This checks for parasites such as worms and Coccidia. Coccidia are a species-specific protozoa that commonly affect young or immune-suppressed pets. As for worms, most animals with light worm loads do NOT have worms visible in their stool, so please don't get a false sense of security that your pet is worm-free just because you see no worms! The fecal float helps us identify intestinal worm infestations by showing those worms' eggs. If the worms inside the pet are not reproductively mature or simply not shedding eggs on a particular day, this test may be falsely negative for worms.

The fecal smear helps identify a bacterial overgrowth of the intestines. Every normal gut has a mixture of beneficial bacteria that help digest the food and provide essential nutrients. A wide variety of internal or external factors can destroy this delicate balance and cause abdominal discomfort and/or diarrhea. Luckily most abnormal findings on the fecal smear are not contagious to other pets and people.

Meet Giardia

The final part of the complete fecal test a Giardia "snap" test. This is a highly accurate test to identify active Giardia infections. Giardia is a contagious and zoonotic (i.e., affects people) protozoal parasite that is  common in the environment. The parasite unfortunately also rears its ugly head in shelters and breeding facilities from time to time.

Lo and behold, while the first two tests showed no significant abnormalities, the kitty's Giardia test was an obvious positive. Wow! Even though the kitty's stools have appeared pretty normal, she has an infectious and contagious medical condition. This is the most likely explanation for poop on the couch and rug, NOT a behavioral quirk. 


The good news is this kitty has a treatable medical condition rather than a behavioral problem. The bad news is all the dogs and cats in the house need treatment because of their close quarters. Shed in the feces, Giardia cysts (i.e., eggs) can remain viable in the yard, litter box, bedding and pets' fur and cause re-infection, so a thorough environmental scouring is necessary. The pets were bathed, their bedding and litter boxes washed, and the yard picked up. Each pet is currently undergoing treatment for Giardia to be on the safe side. The owners have been warned to practice good hygiene when handling the animals and to contact their physician for further advice regarding the zoonotic nature of this parasite.


It is said time and again in veterinary school, "You miss more by not looking than by not knowing." Even though the stool appeared normal and there were plenty of possible explanations for the couch poop, we discovered an important medical problem with our thorough test. Thank goodness we checked! And I'm sure the owners will feel the same way after they've completed a hellish week of medicating three feisty felines!