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Giardia Positive without Symptoms

July 14th, 2007, 11:19 AM
Hi, This is a question I hope Dr. Lee and others on the forum can respond to.
I currently have 3 dogs that test positive for Giardia antigen but are mostly without any symptoms of the infection. That is they are positive eventhough their stools are firm and nicely formed and they are not currently sick. So, why did I have them tested you might wonder? Reason is one is a puppy that I want to enroll in a puppy class. To participate in the puppy class current vaccinations and fecal exams are required, including a SNAP Giardia Test (for antigen detection) and Giardia Vaccination. My vet did the test and my puppy is positive for Giardia. Had my other two dogs tested, and they are positive as well.

To back up abit, my puppy has in the past two months had two recurring bouts of soft stools with mucous/blood. One, right after bringing him home. My vet did not find any parasites by fecal exam, and otherwise puppy did not seem sick. She put him on Science Diet I/D and yogurt. It took about a week and half for his stools to be nice and firm again. Perfect ones. Was relieved! But then, in about a week and half this repeated. Back to the soft stools with mucous/blood. Fecal exams were again negative. Since it cleared up before with Science Diet I/D and yogurt, we did this again. In a week his stools were firm again and they have since remained firm.

So, now I wonder if the Giardia is the cause of the recurring soft stools? I did notice him pooping some wood stick pieces out, so I don't know if this is part of the problem as well. Also was wondering if sometimes vaccinations can cause the soft stools as he was getting vaccinations during this time. So other variables as well, but now testing positive for Giardia makes me think this is the cause. Is it possible his immune system is fighting off the infection and that is why it clears up but comes back? Is it possible some strains of Giardia cause more severe diarrhea than others? My other two dogs that are positive have not had any symptoms, except maybe a "slightly" soft stool on occasion. I understand that giardia is a pretty common parasite in the environment, especially water related, but is it getting to be a more prevalent infection in dogs? Or, is the detection of giardia in animals easier now with the SNAP Giardia Test vs fecal exam alone?

All my animals are getting treated for infection by metronidazole.

Thanks in advance for any responses! Much appreciated!! I hope this post isn't inappropriate for the forum. Thought is was good for everyone to have a heads up!

Dr Lee
July 14th, 2007, 11:44 AM
I am running in between exam rooms this morning, so this is a quick post. This is great website from the makers of the snap test. Here is an educational video. There are a lot of pros and cons to testing as the giardia test can be positive for pets that don't need treatment - i will try to respond later today with more info.

See if this helps. :pawprint:

Dr Lee
July 14th, 2007, 02:01 PM
When you watch the video, you will understan why false positive are rare. So treatment is a good idea. Metronidazole or fenbendazole are the most common treatment options.

The giardia snap test:
Pros: highly sensitive and low false positives
Cons: once the pet has been treated, many will continue to show positive. And many of these patients, those without symptoms, do not require treatment.

Chronic or recurrent diarrhea - yes, giardia can definitely do that. There probably is a lot of info on this sites encyclopedia. Also our hospital website has a info page on giardia.

So I think the requirement of testing is a good idea - we test dog and cats all the time and most of the positives are suprises to the owner. Also people can get giardia - while unusual for people to get the infection from their pets; it has been known to happen. Treating is a good idea. Follow up testing, if the patients are without clinical signs can be murky. If the follow up test is negative then the giardia has been taken care of. If the test is positive on the float - then infection persists, if the snap test only is positive then the answer is unclear. Some patients will test positive usually for up to two weeks after treatment however some may persists for months. I treat each of these situations a little different - it depends on the pet, lifestyle, history and the people the dog is exposed to. Giardia does have a high rate of re-infection and I have had some pets have persistent infections despite treatment. So re-testing is a good idea, just understand that if the snap test alone is positive - it may be a little difficult to know.

Snap test or routine fecal test? Which is better?
I use them in different situations and often together. The routine fecal is a good test for other parasites as well as giardia. Roundworm infections are common, easy to get and not only contagious to humans, but highly dangerous to people. Snap test for giardia won't help with this one.

Hope that answers some of the questions. :pawprint:

July 14th, 2007, 02:16 PM
I think the key here is persistent re-infection in multiple-dog households and low-grade infection. Having lived through severe giardia tiwce ~ I have ZERO problems with admin'ing metrodiazinole. While I'm not a fan a Science Diet and would work very hard to get puppy off the diet...if it's working for now with the met. ~ good on ya !

But bear in mind a re-test for parasites wouldn't be a bad idea given their life cycle and that dogs can have multiple parasites and bacterial/ viral infections at the same time.

July 14th, 2007, 05:56 PM
Dr. Lee the educational video link you provide is great!:thumbs up It is good in a way to hear that the giardia snap test has low false positives. I like to be confident in testings. I think from both your and mummummum's response, that the most parsimonious answer is that it is highly possible my pup's stool issues are due to giardia. Since all my critter's symptoms presently are very mild, it is likely this reflects a low level of infection. My vet intends to re-test them 2 weeks after finishing the medications. I think at that point we start the vaccinations if the tests are negative. I understand the vaccination does not prevent infection, but helps reduce shedding of the cysts in the feces. So, being vaccinated would reduce symptoms and also help reduce contamination in the yard. So, would it hurt to go ahead and vaccinate them now, rather than later? I am guessing the vaccine would interfer with the giardia snap re-test and give a positive result since the vaccine contains giardia antigen? Reason I want to go ahead and vaccinate is that it is required for the puppy class.

My puppy is currently on 50% Science Diet I/D and 50% Canidae lamb and rice. He's been on this for a week and is doing well. I do want to get him on just the Canidae lamb and rice, but thought I should not change too many things at a time. Maybe get him through the medications before changing the food any more.

I have been bleaching my poop scooper with 1:30 bleach and getting poop picked up ASAP. Should I do any further decontamination in the house/or yard? Should I NOT water the lawn? I haven't been overwatering, just a little by hand... thanks again!!

Dr Lee
July 14th, 2007, 08:20 PM

The giardia vaccine question - does it interfere with testing? It does not; remember from the video shows that the snap test reacts to CWP (cyst wall protein). Many other snap tests react to antibodies where the cross reaction to testing occurs. (Good question!)

There is thought that the giardia vaccine helps treat persistent and recurrent giardia infections - this is likely due not only to increased antibody creation but to the reduction in shedding which helps reduce self re-infection. :pawprint:

July 14th, 2007, 09:43 PM
Dr. Lee I appreciate your willingness to help out!:) I will talk with my vet some more also. Thanks again!

July 16th, 2007, 02:23 PM
I've had a chance now to talk more with my vet and also the dog trainor who is doing the puppy classes. My vet is suggesting I wait until my puppy is negative by the giardia snap test before starting vaccinations. He agrees with Dr. Lee that the vaccination will not interfer with the giardia snap test result. But, he is considering that it is best to not vaccinate while my puppy is positive for giardia. It is possible the vaccination will not be as effective if we vaccinate while he currently has a giardia infection. From talking to the dog trainor, who teaches both puppy and adult classes, they are finding puppies frequently being positive for giardia and not having symptoms. That this is less frequent in the adult class.

So, my buddies should be finishing their meds this week, then in two weeks they will be re-tested by giardia snap test. If negative, then vaccinate. Crossing my fingers for the negative!!

August 3rd, 2007, 08:46 AM
My dogs finished their meds and have now been re-tested for Giardia by Snap Test. Winston and Apache are negative. :thumbs up Spencer is still positive. He's a poop eater and I am guessing that is why he is still positive. I pick up the yard immediately, but he is so quick! :frustrated: Vet has put him on a different med, panacur for 5 days. My other two will get vaccinated today. Then Winston's puppy class starts on saturday!! :dog:

I still haven't seen much in the way of symptoms. A few soft poops is all I have noticed beyond the initial problem Winston had on coming home.

I feel lucky after hearing about other pups that have had a much harder time with Giardia. :grouphug:

Dr Lee
August 3rd, 2007, 09:32 AM
Panacur is my favorite for giardia! Good luck! Giardia can sometimes be very frustrating.

February 20th, 2010, 06:38 PM
I'm looking for advice on how to eliminate giardia in my Tamaskan puppy. She is 17 weeks old and has had giardia since she was 10 weeks of age (positive via fecal float & ELISA tests). We treated her first with 8 days on metronidazole. It did not eliminate the giardia. We treated next with 3 days on Panacur. Fecal test was negative, but ELISA was positive. We next treated with both metronidazole and panacur. Fecal float AND ELISA are still positive. She is otherwise healthy, playful, still growing, and has a good appetite, but has extremely foul farts and her stools are getting looser. I have started her on yogurt to replenish her gut flora and on our vet's recommendation, will start her on Panacur & metronidazole again. Does anyone have any suggestions on what ELSE we can do? I don't know why she isn't responding to the treatments. Please provide guidance on treatment and how to sanitize her grassy pooping area! Thanks!