Empirical Deworming in Tortoises is Potentially Fatal in Tortoises.

deadheadvet

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For all of you who insist on deworming without doing a fecal analysis, reconsider your decision. Tortoises are extremely sensitive to many medications. Here is the proof.

Hematologic and plasma biochemical changes associated with fenbendazole administration in Hermann's tortoises (testudo hermanni)
J Zoo Wildl Med. December 2005;36(4):661-72.
Donald L Neiffer1; Dianna Lydick; Kyle Burks; Donna Doherty
1Disney's Animal Programs, Walt Disney World, P.O. Box 10,000, Lake Buena Vista, Florida 32830, USA.

Article Abstract
Toxicosis associated with benzimidazole anthelmintics has been reported with increasing frequency in zoologic collections. Clinical signs, clinicopathologic abnormalities, and gross and histologic lesions are primarily the result of damage to the gastrointestinal and hematopoietic systems. Profound leukopenia, especially granulocytopenia, is the most common and severe clinicopathologic change associated with benzimidazole administration. Death usually occurs from overwhelming systemic bacterial and/or fungal infections secondary to severe immunosuppression. In this 125-day study, six male Hermann's tortoises (Testudo hermanni) were treated orally with two 5-day courses of fenbendazole 2 wk apart at a dosage of 50 mg/kg. Serial blood samples were used to assess hematologic and plasma biochemical changes before, during, and following the treatment period. Although the tortoises remained healthy, blood sampling indicated an extended heteropenia with transient hypoglycemia, hyperuricemia, hyperphosphatemia, and equivocal hyperproteinemia/hyperglobulinemia, which were considered to be in response to fenbendazole administration. Changes in several other clinicopathologic parameters appeared to correlate with fenbendazole administration. The hematologic and biochemical changes seen in the healthy animals in this study should be considered when treating compromised tortoises with fenbendazole. Hematologic and plasma biochemical status of tortoises/reptiles should be determined before treatment and monitored during the treatment period. The risk of mortality of an individual from nematode infection should be assessed relative to the potential for metabolic alteration and secondary septicemia following damage to hematopoietic and gastrointestinal systems by fenbendazole.
 

wellington

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Thanks for sharing. That's why I never treat, if there is nothing there to treat. To do so is just poisoning. IMO
 

Tom

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Thank you doctor.

Can we get more info from you?

What should the "average" keeper do that sees no obvious problem with their long term tortoise? Should they test, but not treat? Not bother testing if everything is fine?

Are there wormers to favor AFTER a positive diagnosis and if needed?
 

Elohi

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Thank you for this!

This makes me REALLY freaking nervous. I wormed my entire group when my foster came up with some very mobile but unidentified protozoans and nematodes. My group had shared space with the foster so I dewormed them all and I've seen some issues as a result.
My youngest, smoothest, most perfect baby that I hatched myself stopped eating and his growth halted after being wormed. He also slept tons. After a couple of weeks he started eating again but his growth has still not picked up after 4 months. He lost weight and has regained it but still has not grown despite his rapid rate of growth prior to being dewormed. I am still nervous about him even though he eats great and acts normal.
 

Kapidolo Farms

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At that dose rate they were doing a TK response study. This is one of the things I do at work, dose animals to the point of seeing a toxic response. That is what this study is. They don't call it that, but it is a TK study.

http://learnpkpd.com/2011/02/15/what-is-the-difference-between-pk-and-tk/

They overdosed on purpose.

No formulary for reptiles even comes close to suggesting that high a dosage rate. http://www.merckvetmanual.com/mvm/exotic_and_laboratory_animals/reptiles/management_of_reptiles.html table seven. A (just one) dose every five to 7 days, not five days of dosing twice.

A better safer drug is Oxfendazole, the common go to drug in Europe.

I know I'm not a veterinarian. I do oncology research on small and some not so small lab animals.

That not withstanding, I agree drugs should not be used willy-nilly.
 

deadheadvet

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Best advice which I have repeatedly mentioned until I am blue in the face, is to have fecals run on groups or individuals and decide if treatment is indicated based on the findings. Fenbendazole can be used when indicated, not as a general empirical dewormer. Calculations should be done correctly and followed as well. I am not here to give dosages. As far as I am concerned, you administer meds on your own, you get what you deserve. I always check fecals on new additions but thereafter only if I feel there might be an issue occurring. For those who think the vet is only out there for the money, we all aren't like that. We also went to school for 8 years to be licensed to treat animals and prescribe medications at the appropriate doses. For those who think otherwise, save your money and proceed at your own peril. Nobody said keeping tortoises was an inexpensive hobby.
 

deadheadvet

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A follow up to Tom's question.
Know your species, aquatic turtles are more likely to contract protozoal organisms
Land tortoises if wild caught can have any and all the above (another reason not to purchase wild caught animals)
No what is harmful and what is not. Request a copy of the fecal results from the vet and decide whether it should be addressed. Get educated on what is considered normal flora and what isn't. If I was dealing with a significant parasite issue, i would pick the medication that would address the issue at hand.
When properly indicated, Metronidazole and Fenbendazole would be good choices.
 

ZEROPILOT

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Interesting. I've used Metronidazole with my fishes. In fact, it once saved a very large fish that had been kept in filthy situations.
I used Panacur to deworm a tortoise a few years ago. I got the Panacur and dosing chart from my old vet. And was told that I should treat as a preventative every six months my whole group. Something I've been reluctant to do.
This is the first thing I've read that is contradictory to that. I've never been really comfortable with it. (This was from a vet I no longer deal with.)
Thank you for your input. It makes sense and I will stop "random" treatments.
It's kind of like going to different mechanics and getting different advice on the same problem.
 

deadheadvet

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Just to follow up on Will's comment, it was a PK study to determine blood levels of drug and ultimately any side effects produced at the dosing rate. The take home message is any medication can be fatal under certain conditions. Why give something if there is no indication for it. Would you take Advil if you didn't have a headache?
 

ZEROPILOT

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Just to follow up on Will's comment, it was a PK study to determine blood levels of drug and ultimately any side effects produced at the dosing rate. The take home message is any medication can be fatal under certain conditions. Why give something if there is no indication for it. Would you take Advil if you didn't have a headache?
Thanks for the article.
 

Kapidolo Farms

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Just to follow up on Will's comment, it was a PK study to determine blood levels of drug and ultimately any side effects produced at the dosing rate. The take home message is any medication can be fatal under certain conditions. Why give something if there is no indication for it. Would you take Advil if you didn't have a headache?

If they are dosing at five times the recommended protocol, in an off label usage, they are doing a TK, not PK. Regardless of what they may have narrated as the purpose of the administration of the drug, they were looking for an exposure limit for an off label use, and at five or more times common practice for chelonians. They may very well have used higher doses and simply not reported it.

The driver in the decision making process in evaluating the efficacy of a drug involves two general questions, 1) How little of the drug will bring desired result, and 2) How much of the drug will be detrimental to the patient. This is first done, today, with modeling/simulation based on other similar compounds, then on cell lines, then on small animals as models of the intended patient, then clinical (human or otherwise). A second pre-clinical evaluation is then done of female animal models while pregnant to look for teratogenic concerns and evaluate yolk or milk etc.

As safe dose limits have been determined for fenbedazole use to eliminate some worms in chelonians published in the Merck manual it strongly appears these investigators dosed at 5 times that rate - they were looking for toxic effects, a PK study. Range finding studies are an important contribution to the safe use of compounds. A few vets I have spoken with specifically about this exact study, have come away with LESS concern for over prescribing/over dosing it, not more.

Another growing pool of interest that suggests giving animals any kind of drug that influences their micro-biome is that it can cause damage by eliminating some flora required for nutrient extraction. But that is way off point here. Many herbivorous reptile have places in their gut that hold small pockets of food during brumation, aestivation, and times of no food availability for the speculated purpose of keeping a small gut flora.

So despite my not agreeing with the point of the study as a TK not PK investigation, I do agree it is best to not use any of these compounds without knowledge or guidance by qualified people.

DeadHeadVet's point about Advil and why take it if you don't have a headache is spot on.
 

domalle

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Just to follow up on Will's comment, it was a PK study to determine blood levels of drug and ultimately any side effects produced at the dosing rate. The take home message is any medication can be fatal under certain conditions. Why give something if there is no indication for it. Would you take Advil if you didn't have a headache?

But I am not a captive wild animal kept in confinement under artificial conditions where proliferation of parasites
can occur through recycling in the enclosure environment.
I have used fenbendazole for many years with no adverse consequence. I no longer treat prophylactically as a routine.
But if I have evidence of an active parasite "burden" in any of the animals on the same plot of land even in separate enclosures,
I treat them all as a precaution.
 
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