Another unfortunate leopard gecko issue

Not since this last gecko. Everyone else appears to be in good health. I never put this last gecko out of quarantine since his issues never fully went away.

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Good call. Hopefully everyone else in your collection will remain safe.:crossed_fingers:

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I’ve been puzzling over this case, and I was able to get my mom to help me unpack some boxes (I’m disabled, not just lazy, :grinning_face_with_smiling_eyes: heh), and we found some of my veterinary texts. I’ve been looking through them, and I haven’t found a ton of info. So far, this is what I’ve found:

Internal abscesses form (in reptiles) when the pathogenic organism enters via the skin (wound or insect parasitism, like mites), gastrointestinal tract, or lungs. Once in the body, the organism can be spread via the blood circulation. Since Salmonella is often present in the GI tract of reptiles, that would make sense. The question would be whether there was a physical lesion on the GI tract that allowed entry (such as by something ingested that was too large, a blockage, or even just a random fluke occurrence, maybe), or if the immune system was compromised from something else, and it failed to prevent Salmonella from leaving the gut. Though I should point out that there are other bacteria that could behave like Salmonella & cause similar symptoms. The immune system can be compromised by having a congenital defect, but also as a result of environmental/husbandry conditions, and tons of other stuff, I’d imagine.

Also found a reference that reminded me that any animal that’s being raised together in large numbers is more prone to having higher carriage rates of Salmonella in the population, though that just means that they are carrying it (as many/most reptiles do), not that it makes them ill.

And I also had a thought- as leopard geckos are insectivores, any breeder could develop problems if they are buying their feeders from somewhere else, and the company raising the feeder insects feeds them unwashed/contaminated fruits or veggies. Also, it’s common for leopard gecko breeders to feed diets that are too high in fat (mealworms). So food source could potentially be involved.

I did find some references that might have more information, but I don’t have access to them (a library should understand the notation & may be able to get the article/book chapter for you via inter-library loan, and your vet should understand the content itself):

Onderka DK, Finlayson MC: Salmonellae and salmonellosis in captive reptiles, Can J Comp Med 49(3):268, 1985.

Frye FL: Infectious disease: fungal actinomycete, bacterial, rickettsial, and viral diseases. In Biomedical and surgical aspects of captive reptile husbandry, Melbourne, Fla, 1991, Krieger Publishing.

Mitchell MA et al: Salmonella in reptiles, Semin Avian Exot Pet Med 10:25-35, 2001.

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Okay, I finally had a chance to read through all this and I have some questions/thoughts:
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What was the dosage they prescribed? Possibly irrelevant, but in high dosages it can actually be toxic
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Do you know which strain they tested for? There are a couple different ones that pass through the hobby and they are able to cross-infect. If (if, If, IF) the snakes from the other vendor were a vehicle for a nasty crypto but it was a species more commonly associated for snakes but the vet tested for the common lizard strain, then the test would have missed it.
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No where in the histology is Salmonella mentioned prior to this point, so when/where did they make this differential? Further, the simple presence of Salmonella is, to my, fairly irrelevant because most reptile harbour the bacteria as part of their native flora. For a determination of actual salmonellosis, you need a type/strain level identification.
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Some of my thoughts-

I would agree with the assessment of systemic sepsis from the endocarditis abscess, however, endocarditis is rarely caused by gram-negative bacteria, so Salmonella seems less plausible to me as a cause here unless it was directly sampled at high burden from the abscess. Additionally, Salmonella appear to be naturally resistant to metronidazole, so it seems somewhat illogical that the animal would show improvement before sudden collapse if we were exclusively dealing with a Salmonella infection. My personal suspicion is that there is/was some other bacteria present that was the cause of the infection and that the metronidazole was bringing it under control however, as the drug became effective, the biofilm like quality of the bacteria within the abscess became compromised and you had sloughing of material that lead to a blockage somewhere critical resulting in a myocardial- or stroke-like event.

I fully admit to that being entirely supposition, but the positive improvement after treatment with metronidazole just does not sit right with me for salmonellosis

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Reading through this information with each post is just fascinating to me. Invaluable information here.

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My primary experience with this is with mammals, but in mammal patients with gastroenteritis of unclear etiology, metronidazole is often prescribed because it has a ‘soothing’ effect on the GI tract that, last I heard, vet med was unable to explain. I know that sounds totally nuts, and I definitely have a bad memory, but I’m pretty sure of that. I just don’t have a reference because it’s one of the things GP Small Animal vets just sort of know.

If (and that’s a big if) the reptile GI tract displays the same phenomenon as mammal GI tracts do, I wouldn’t find a small positive response to be that abnormal in unexpected situations. It makes me wonder if (another huge if) perhaps there was an issue with the GI tract mucosa, which was improved/resolved by the metronidazole, but only after the normally comensal, but now pathologic agent had crossed the mucosal barrier into the circulation & established a nidus of infection. Just a thought.

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I have heard this as well and the prevailing theory, last I heard, was that the clearing of parasites after a treatment offered relief that made them more comfortable with feeding. Seemed a little too nebulous an explanation for me though if I am being honest

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So, I read through this thread, and as a complete outsider, I’m wondering why metronidazole was administered in an animal with a clean fecal instead of opting for a bacterial culture to see if that was the issue. Metronidazole can be mutagenic to some strains of Salmonella in certain conditions, so it might’ve been a bad choice in this particular case.

Actually, this is likely exactly why the vet suspects some form of congenital immunodeficiency issue. Salmonellosis doesn’t usually lead to septicemia, except in the case of an immunodeficient animal. For example, in humans with HIV, Salmonella septicemia is considered an AIDS-defining condition as it is a life-threatening opportunistic infection in HIV+ individuals. In animals, severe Salmonellosis causes pretty much everything listed in the histopathology report. Salmonella bacteria colonized the heart, spread system wide, and the body’s inflammatory response caused further damage resulting in death.

The only real way to confirm this is a genetic immunodeficiency issue would be to talk to the breeder and check on other animals both in their collection and sold with similar genetics and see whether there is a pattern of unusually early demises or severe illness with unknown etiology.

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Yes but the point I was trying to make was that, in the absence of evidence for a congenital defect, the presence of Salmonella alone is not a differential diagnosis given that all reptiles carry the bacteria. To me, it more comes across as an “easy out” to take.

But again, that is just my take on the matter

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It may come across to you as an “easy out” but it’s all evidence based. There have been studies done on Leopard Geckos and Salmonella is actually a very common bacterium passed from animal to animal that is normally not problematic, but in animals with weakened immune systems, leads to all of the symptoms described above, including death and the histopathological findings. It’s often an issue in animals suffering from vitamin A disorders, specifically.

I highly suggest this article for further reading. I also think it’d be a very good idea for @fatalis to contact the breeder because there is the possibility that it could impact their entire collection.

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Thank you all for the continued responses. I apologize for the delayed response, Black Friday weekend into Cyber Monday were pretty intensive and took all my attention due to work.

To answer your questions, Wyman:

  1. I do not know the dosage off hand but I could potentially find out from my vet if you think that will lead to anything.

  2. On the paperwork I got from the vet all it says is “Test: Cryptosporidium Genus”. So I am unsure, but again can ask my vet.

  3. I double checked the results paperwork from the histo, and as you mentioned it is not stated anywhere else about Salmonella. I copied over pretty much all the important bits.

I have been in contact with the breeder, though at this point all that has been said is that they are reviewing the message I sent. I have been waiting for further communication for about a week now and am hoping to hear back from them soon.

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