Blood worms vs poop worms

Right here by popular demand: It's blood worms vs poop worms.  No it's not a WWE match.  But it is something I get asked about all the time.  And it is something that causes great confusion in the exam room.  So my office manager and vet assistants asked that I write this blog to try and clear up some myths about worms that we hear all the time when talking to pet owners.  So here are the top 5 worm myths that we hear.

Myth #1

I'm sure my pet doesn't have any worms because I don't see anything in its poop.

Answer of course is "seeing" or in this case "not seeing" does not tell you what is happening inside a dog or cat's intestines.  Tapeworms may the one exception as most tapeworm infections in dogs and cats are diagnosed when the owner either sees the worm segments in the animal's poop or sees the worms actually crawling out their pet's butt while they are snuggling together in bed.  Nice, eh?  These segments are where the tapeworm eggs are found and that is how they reproduce and spread.  But the other major worms (roundworms, hookworms and whipworms in dogs) just tend to happily attach to the lining of the pet's intestines eating and having sex.  Then they produce eggs that are passed into the poop and worm eggs are microscopic.  Adult roundworms are large enough to see easily, but adult hookworms and whipworms are much smaller and rarely if ever seen.  Unless there are hundreds of adult worms hanging out in the intestines or they are killed with deworming medicine, there is no advantage for these adult worms just let go and pass outside the body.  So they just hang onto the inside of your pet and pass microscopic eggs into the environment.

Then there are all the single cell parasites out there like Giardia and Coccidia.  They are not worms at all, but can make pets pretty gosh darn sick.  I challenge anyone out there to be able to see a single cell organism with the naked eye.  Ain't gonna happen.

Did you know that a single female roundworm can produce 100,000 of these microscopic eggs every day? (From CDC web site)

Myth #2

My pet had a negative stool sample, but I am seeing worms.  Your stool sample test sucks.

Answer is that the test does not suck, but it does have limitations.  Worms don't always produce eggs every single day of their lives.  Some worms are more likely to produce lots of eggs (roundworms) then others that produce few eggs (whipworms).  And as I mentioned above, tapeworms like to pass segments through the stool.  The eggs are inside these segments and that is what the fecal test picks up.  So if there is no segment in the poop sample, it will be negative.  Your pet still has worms. 

We still recommend stool samples be tested though because they are a good screening tool.  They will pick up a lot of worms that we would never know a pet has just by looking at the poop.  You just have to remember that once in awhile, a "negative" is not truly a negative.  (If you look at our medical records, we actually don't write "negative" in the results box, but rather we write "no ova(eggs) seen".)

Myth #3

We tell you your dog needs to be tested for heartworms.  You say that you brought in a stool sample a couple weeks ago and it was negative for any worms.

Answer is that HEARTworms live in the HEART.  So when they reproduce and have children, they do it inside the bloodstream.  You will not find baby heartworms in a poop sample.  We need to draw blood.  Adult heartworms live in and near the heart and when they give "birth" it is to little squiggly larvae called microfilaria.  Again, these microfilaria are microscopic and just waiting for a mosquito to suck up some blood and carry them off to another dog, cat, coyote, or whatever.  There are blood worms and there are poop worms.  Heartworms are in the blood.

Myth #4

My dog can't have heartworms because it is not around any other dogs and it hardly ever goes outside.

Answer is that heartworms are spread by mosquitoes and while you may not want to admit it, mosquitoes can and do get inside our homes.  Mosquitoes can also travel a good distance when the wind blows whether they like it or not.  My best example was a little dog that came to the city clinic where I worked about 20 years ago.  It was a little toy poodle that lived in a high rise apartment and pooped and peed on a pee pad inside the apartment.  Yep, the poodle got heartworms. 

Myth #5

My dog can't have heartworms because it doesn't even act sick.

Answer is that depending on how many heartworms are in a dog's heart, they could walk around for years before they start showing symptoms (coughing, getting tired more easily).  Dogs with lots of worms will show signs right away, but some dogs will only have a few worms.  By the time that they get symptoms, they are at risk for permanent lung or heart damage.  We need to test all dogs before they are sick.

Now if you read my last blog, you read about a lovely picture of bloody diarrhea that came out of a dog and ended up on the floor of the waiting room.  This dog's diarrhea was caused by massive hookworm infection and there were a few tapeworms thrown in for good measure.  If you don't want to look, then don't scroll down.  You have been warned.

The moral of the story is listen to your vets when they speak of worms.  Worms are a fact of life in dogs and cats and trying to ignore that worms exist can lead to trouble.  Let's keep our pets and families healthy!