Tick Born Disease Testing

[cometdust1]

I have a greyhound that I adopted a year ago that I would like to have a tick panel done on. He is asymptomatic but I recently lost a greyhound that had ehrlichiosis.He was asymptomatic for 4 years and by the time he showed symptoms he was already in the chronic stage and it was too late for him.What is the most accurate way to go about this? I'm confused about the different ways the tests are done.

[Booker_Aye]

http://www.protatek.com/reflab.html

 

 

I believe that the gold standard for testing greyhounds for tick borne illnesses is Protatek: Dr. Holland, the lab chief, is extremely knowledgeable on the topic. The lab has several tick panels to choose from, or you can put together the tests that you feel are most important for your hound. They are incredibly reasonable in price, and offer a discount for greyhounds. You can access the forms and instructions for how to submit serum for samples from the web site and bring the information in for your vet. I recently had my Fred tested because his SNAP test had indicated that he had chronic Lyme and another tickborne illness, and the local lab where my vet sent followup tests just didn't satisfy my concerns. My vet drew the blood and prepared it for shipment (this was on a Saturday) with an icepack inside, and I drove over the Federal Express and shipped it to Protatek for Monday delivery. When Dr. Holland gave Fred a clean bill of health, I felt secure. The results were available within 24 hours. I am sure if you search "Protatek" on this forum, you'll get many positive reports. I am so sorry to hear about the way you lost your greyhound. I just hate ticks more than I can say -- such nasty beasts they are!

[tbhounds]

I'm going against the grain with the last poster (seems I'm good at that!)--- I would rather see the op send bloods out to ncsu :-)

http://www.cvm.ncsu.edu/vhc/csds/ticklab.html

[JJNg]

I prefer the NCSU Tick Lab as well. However, I usually don't recommend testing asymptomatic dogs. I understand your concern given your previous experience, and it wouldn't be wrong to test. But in most cases, TBD testing is complicated enough as it is and not always definitive even with a sick dog.

 

Positive titers only prove past exposure and do not necessarily indicate active disease, while PCR has a fairly high rate of false negatives. So positive titer results then lead to the dilemma of whether or not to treat. And a negative PCR might create a false sense of security. If you're determined to test, I'd probably do both antibody titers as well as PCR to the full panel of TBD.

 

Sorry to hear of your previous experience and loss due to chronic ehrlichiosis, but earlier testing may not have changed anything.

[greyhead]

We found one of our dogs' Babesia and later Lyme, using Protatek. In both cases the titers were low positive, in both cases we elected to treat (after due consideration and consultation), and in both cases it made a world of difference in his quality of life. Of course, he did have symptoms, but not really scary ones yet. Some of us here feel that the time to test for TBDs is when you have symptoms (however few or many) that affect quality of life but can't be or haven't been explained by other test results. (But it's important to know that even NCSU will tell you that a negative test result on a PSR is meaningless, that only the positive results are reliable. At least they will if you talk to the right tech.) IIRC, there are some adoption groups that either do or recommend TBD titer testing on all their adoptable greyhounds.

 

Anyhow, just sharing one family's experience. All the best to you and your "new" boy!

Edited March 1, 2013 by greyhead

[Batmom]

A negative PCR result isn't meaningless. It simply tells you that no DNA from the organism you're testing for was found in that sample. Unfortunately, that doesn't mean the organism isn't somewhere in your dog's body. It is thought that some of these organisms can hide out in the spleen, in which case only a biopsy would tell you they're there.

 

Neither antibody testing (titers) nor PCR are perfect diagnostic tests. Antibodies can be very low when a dog is very ill, and can remain high for years when a dog doesn't have the disease. PCRs can be negative when the organism is in tissues but not in the blood.

 

Right now, today, I would say the best test panel available is NCSU's combo IFA (antibody titer) / PCR panel, see here: http://www.cvm.ncsu.edu/vhc/csds/documents/VBDDLTestRequestFormJan2013withComprehensivePanel.pdf

[greyhead]

A negative PCR result isn't meaningless. It simply tells you that no DNA from the organism you're testing for was found in that sample. Unfortunately, that doesn't mean the organism isn't somewhere in your dog's body.

 

That's what I meant by "meaningless." It's the same sense in which a negative fecal is meaningless. In other words, the only way you know for sure that the test result is true is if it's positive.

Edited March 1, 2013 by greyhead

[Batmom]

That's true of many tests.

 

If your dog is very ill -- and not yet on antibiotics -- there are highly likely to be circulating organisms. For a PCR test to be positive, the blood sample needs to snag only one of those organisms.

[greyhead]

But that's like dipping a bucket into the ocean once and trying to pull it back up with a fish inside. At least that's the way the tech at NCSU explained it to me. I'm just repeating what she said. (And it seems reasonable to me, though I don't count for much.)

[Batmom]

But that's like dipping a bucket into the ocean once and trying to pull it back up with a fish inside. At least that's the way the tech at NCSU explained it to me. I'm just repeating what she said. (And it seems reasonable to me, though I don't count for much.)

 

Bad explanation, for the most part. If your dog isn't sick, you're not likely to have circulating organisms. If your dog is sick, you will likely have circulating organisms, and most blood samples will reflect that. Sort of the definition of the disease process. The "fish in the bucket" analogy is better applied to peripheral blood smears although that is still a useful and probably underused test, too.

 

Similar issues apply to titers. If an organism is sequestered (usually thought to be in the spleen, and AFAIK applying mainly to the ehrlichias), the dog isn't going to make antibodies to it.

 

This is why some experts recommend using both types of tests, paired (pre-treatment sick and post-treatment convalescent), when an animal is ill, and why most don't recommend testing an animal who shows no signs of illness.

[greyhead]

The fish in the bucket analogy is intended to address the probability of obtaining a positive result given the sizes of the materials in question: all the blood in the body and the microscopic material. That's how I interpreted it anyway. Then tech also said that the DNA material being sought with the PCR is analogous to the skin cells we shed, only these are the "skin cells" of microscopic organisms. Pretty small! This material is most likely to be found hiding (caught) in the smallest blood vessels, the capillaries, such as in the ears, I read. So that sounds like a method with a higher probability for finding what we're looking for, looking at it on a slide, and even then one might want more than one sample. I'm sure that's Old School, but I like it. It's also Old School to go ahead and treat if the dog is symptomatic and the test results equivocal, and I like that too.

 

ETA: Just one other thought. From what the tech said, you're not picking up circulating organisms in a PCR sample, you're picking up dead parts of them. So that sounds like a fecal that looks for and finds eggs, not actual worms. It has been several years since I looked into this for Shane, so my memory of it has faded somewhat.

Edited March 1, 2013 by greyhead

[Batmom]

Your tech's explanation is poor, and outdated besides. For one thing, size doesn't matter. For another, different organisms behave differently. Even with babesia, it's sheer dumb luck to see it on a slide unless the dog is carrying a very high load. The gold standard single test for babesia is generally considered to be PCR.

 

The rest -- I'm not sure what your point is. There is a difference between treating a sick dog, with specific symptoms, and testing a healthy one with none.

[greyhead]

My point? That PCR testing is not infallible.

[Batmom]

Nobody said it was.

[cometdust1]

Thanks for all your information,I understand a little bit better why it probably wouldn't do any good to test if he has no symptoms.I had my ehrlichiosis grey for 4 years before he showed symptoms,and it was another 6 months before we knew what was wrong.His early symptoms were very mild,we took him to the vet and he thought it was just allergies.He had a slight cough,runny eyes.He had his yearly snap 4 test which was negative at that time.He was 7, so we thought the slowly increasing lethargy was aging.When I took him back to the vet 6 months later he had uveitis and was very lethargic.He ran the snap test again and it was positive.He referred me to an internist . The appt. was in 3 days. 1 day later I took him there as an emergency because he just was laying in the yard when I let him out to go to the bathroom.Turns out his bone marrow was already shut down and all his organs were enlarged.We tried treatment with antibiotics and steroids but it was too late.I let him go about 2 weeks after that.At least now I know the symptoms so I can get him tested and treated sooner if anything should show up.Thanks again everyone.I am definitely a more educated greyhound owner because of this site!

[Guest DeniseL]

I'm reading this thread with interest. My boy has an enlarged spleen, is generally lethargic, has itchy, red eyes, and on again, off again, GI upset. We have an appointment on Monday. I will be getting him tested...

[Batmom]

It can do some good to test if the dog doesn't have symptoms. Just, it can be hard to interpret some types of test results if the dog seems healthy. You'd always (with a few odd exceptions) want to treat a positive PCR or an exceptionally high titer. In-between titers, the lab and your vet might want to discuss. Very low titers and negative PCRs you'd consider negative ... for now. You might want to repeat those low/negative tests later if the dog developed symptoms not otherwise explained, had ongoing tick exposure (rotten things are ubiquitous), or simply for peace of mind.

[Guest Lefty]

I just got a consult from OSU regarding this. My girl, Joppa, had very low platelets and was Snap postive for erlichia. My boy, Dothan, was Snap negative. They recommended I get them both tested by ncsu. They both came from the same farm and same kennel. Both came home with ticks on them but were asymptomatic.

[greyhead]

Here is a terrific, detailed, informative discussion of this subject, mostly between Batmom and JJNg a little over a year ago. http://forum.greytalk.com/index.php/topic/280685-sams-mystery/?&p=5112465&fromsearch=1

 

[cometdust1]

What is the potential down side to treating an asymptomatic dog that has a positive tbd test? I know they may not have active infection just because the test came back positive but I would be afraid to wait and see if any symptoms show up before treating.

[JJNg]

Depends which TBD the dog tests positive for. Most of them are treated with doxycycline, an oral antibiotic that most greyhounds tolerate well. The current issue is that doxycycline is in limited supply and on backorder through most distributors, so you may have trouble finding it. Our clinic still has some left, but I would be reluctant to dispense it for a dog who is asymptomatic, preferring to save it for the dogs that really need it.

 

Babesia is treated with an injectable medication called imidocarb. It is a painful injection in the muscle, and while most do fine with it, there is the potential for complications. Here's a previous thread on this topic.

[Guest Lefty]

I know this wasn't my thread to start with, but thanks for all of the information. I am going to do what OSU recommended and have both my hounds tested at NCSU, but I have a much clearer understanding of what the tests can and can't do. It's very nerve wracking because Joppa has NO outward symptoms AT ALL. If it weren't for her low platelets, you would think she was fine. Also, due to the fact that four other dogs were diagnosed around the same time as Joppa, and both my hounds came home with ticks on them, I would just feel better about testing them. Thanks for spelling out the pros and cons. This is a great message board.