Possible benefits of worms in the gut

[GeoTerraTestudo]

It seems like whenever parasitic worms are discussed here on TFO and other circles, it is to say that they are a great threat to the health of tortoises and must be eradicated. However, I would like to suggest that this might be unnecessary, and perhaps even detrimental. Tortoises with heavy helminth loads should definitely be treated, but what about those with only small numbers of nematodes in their gut? Should they be medicated, too? I would like to suggest that they should not, and offer this topic up for debate.

Since the 1800s, it has been thought that bacteria and parasites are bad, and should be wiped out to prevent disease. Recent research, however, indicates that this is not necessarily so, and that having few or none of these organisms in us may lead to chronic disease. Some bacteria are beneficial to their host, and parasites such as nematode worms may not be all bad, either. Although a heavy parasite load is known to be bad for the host, some new research indicates that a small number of worms may keep the immune system healthy. This may be true for humans and other mammals, and possibly for reptiles like turtles, too (please see "Hygiene Hypothesis" for more information).

Herbivorous vertebrates like cows, horses, tortoises, and some lizards also rely on symbiotic bacteria to help them digest vegetation. Herbivorous mammals (cows and horses) have very long gastrointestinal tracts to provide plenty of time to churn and absorb the digesta, but reptiles do not. So, how does their plant matter get digested?

Nagy (1977, attached) states that some nematodes are known to be cellulolytic, or capable of digesting plant fiber as food. He also cites another study that found many worms in the gut of Uromastix lizards, and suggested that they may actually be important to the lizards' digestion. Perhaps these nematodes actually help herbivorous reptiles like lizards and tortoises by helping them digest their food. Also, given how short the reptilian gut is compared to the mammalian gut, maybe these parasites help increase the surface area of the food, making it easier for enzymes to break it down.

Considering how toxic some anti-helminthic medications are, I'd like to suggest that it we may be doing more harm than good if we automatically try to de-worm tortoises, instead of letting them be. Again, I acknowledge that heavy parasite loads are bad for tortoises and other animals, including us humans. However, if having a few parasites in the gut is normal for tortoises and other animals, maybe it is better to allow them to stay there.

What is your opinion? Please discuss.

 

[yagyujubei]

A parasite, by definition, takes from the host, and gives nothing in return. It isn't a symbiotic relationship .Granted, a small number do a small amount of harm.

 

[cdmay]

I tend to agree completely. I think that certain levels of gut 'fauna' are probably harmless, if not actually beneficial. It stands to reason that such things help to break down ingested food items and make them more accessible to the tortoise eating them.
But I will be the first to admit that I often treat newly imported animals almost as a rule if they give the slightest hint of problems. My reasons for this are that I have seen some imports pass huge numbers of various worms and invariably these animals were doing quite poorly. When tested many of these same animals will show high levels of flagellates in their gut too.
For example, I had a tortoise come to me from another keeper a number of years ago that picked at food but just didn't seem to be thriving and was generally lethargic. It passed very loose and runny stools that smelled awful (unlike healthy stools that smell... good? normal? I know, it just doesn't sound right does it?), had some blood in them and were of an odd color. A trip to my vet showed enormous levels of flagellates as well as larger than normal populations of nematodes in fresh stool samples. The tortoise was tube-treated for these things as well as for tapeworms. Within a couple of days the turnaround was remarkable and that tortoise really perked up and started chowing down like crazy. Her stools improved dramatically too. A follow up treatment was given a week or ten days later and then she really took off. In her case treating for parasites was clearly needed.
Having said all of this though I still think that most tortoises that are carrying normal levels of gut critters probably are not harmed in the least and may even do better with them than without.
One thing that I used to do with new imports was to try and 'blow out' their parasite loads with heavy feeding. I would feed new imports anything and everything they would eat in an attempt to overwhelm the parasites and help push these things through the gut system with the large amounts of food. This of course, may make absolutely zero sense and a vet might point out that I was wasting my time. But during a conversation I once had with Rob MacInnes of Glades Herp he told me that he did that very same thing, feeling as I did that it might help bring the parasite loads under control.
One thing I do know is that all of my adult cherryheads will test positive for low levels of various parasites as well as protozoans and they are all doing quite well. And don't forget, every single tortoise that lives in the wild and lives to a great age is carrying at least some 'bugs' in its gut.

 

[wellington]

My only thought is that they aren't treated for parasites in the wild and still manage. However, in captivity, are they missing something that does not keep them in check, that they are getting in the wild? Hmmmm

 

[GeoTerraTestudo]

A parasite, by definition, takes from the host, and gives nothing in return. It isn't a symbiotic relationship .Granted, a small number do a small amount of harm.

That's just semantics. If it turns out that worms actually have a way of benefiting their host in some way, then the relationship is not completely parasitic after all.

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My only thought is that they aren't treated for parasites in the wild and still manage. However, in captivity, are they missing something that does not keep them in check, that they are getting in the wild? Hmmmm

In the wild, tortoises self-medicate by eating bitter vegetation when their parasite load gets too high (the compounds in the leaves can de-worm them to some extent). Maybe in captivity, if we give tortoises a mix of bitter and bland plants, they will be able to naturally keep the number of nematodes in their gut low.

---

One thing that I used to do with new imports was to try and 'blow out' their parasite loads with heavy feeding. I would feed new imports anything and everything they would eat in an attempt to overwhelm the parasites and help push these things through the gut system with the large amounts of food. This of course, may make absolutely zero sense and a vet might point out that I was wasting my time. But during a conversation I once had with Rob MacInnes of Glades Herp he told me that he did that very same thing, feeling as I did that it might help bring the parasite loads under control.

I think there may be something to that approach. Higher-fiber foods may be better at getting rid of parasites by literally scraping them off the gut wall. Also, nematodes are not immortal, and only live for 1-4 years on average. Unless a tortoise is continually getting reinfected with eggs picked up from its environment, it should be able to lose many of its parasites over time, simply by attrition. I don't know the longevity of protists in the gut, though, or whether they have any "redeeming" qualities the way bacteria and nematodes do.

Again, I am glad people are medicating tortoises that are obviously overwhelmed by parasites. My point, though, is that I am skeptical of prophylactic de-worming practices, because they might not be needed, and may even do some harm.

 

[yagyujubei]

Since my response was dismissed as semantics, please enlighten me with an explanation of how a parasitic worm, which lives off of the blood of the host is a benefit to the host.Does it help get rid of all that pesky extra blood? Your explanation of symbiotic bacteria has nothing to do with parasites.

 

[GeoTerraTestudo]

Since my response was dismissed as semantics, please enlighten me with an explanation of how a parasitic worm, which lives off of the blood of the host is a benefit to the host.Does it help get rid of all that pesky extra blood? Your explanation of symbiotic bacteria has nothing to do with parasites.

Well, I was not dismissing your response. I was simply pointing out that our view of worms and other organisms is changing, such that it may no longer be adequate to consider them only as parasites anymore. Anyway yes, I will be happy to go into more detail.

1) Immune response - There is evidence that certain antibodies (IgE), which cause allergies in humans and other mammals, originally evolved as a defense against parasitic worms. In addition, worms appear to release enzymes into their host's body to modulate its immune response. When worms are present in small numbers, the host's immune system appears to be regulated such that inflammation decreases, reducing the likelihood of chronic autoimmune diseases like allergy and bowel irritability. In this scenario, although worms can harm their host if present in large numbers, the host has evolved to maintain small populations of worms in the gut. This is known as the "old friends hypothesis," and it basically just means that, although worms are parasites, mammals may actually need them to help maintain a healthy immune system. This might apply to reptiles, too.

2) Digestion - Plants are hard to digest, so herbivores have evolved ways to help break them down so they can be used as nourishment. In mammals, this begins with thorough chewing by molar teeth to greatly increase surface area, so that enzymes can have access to the plant fibers and degrade them. However, because vertebrates do not produce their own cellulose-degrading enzymes, they rely on symbionts living in their gut, like bacteria, to produce these enzymes for them. In addition, mammalian herbivores have evolved very long gastrointestinal tracts to retain plant matter for long periods (up to a few days), so that it can be broken down and absorbed. Herbivorous reptiles like tortoises may have longer guts than their carnivorous cousins, but they are much shorter than those of herbivorous mammals like cows and horses, both in absolute and relative terms. Also, tortoises don't chew their food, and they don't necessarily swallow stones for gastroliths, either. So maybe tortoises need help digesting all that plant matter. One possible way for that to happen is nematode worms, which may help out in two ways. One, some nematodes can produce cellulolytic enzymes, the way bacteria do, to help break down plant matter. Two, the movement of nematodes may help churn the food bolus in the gut, increasing its surface area and speeding up its rate of digestion. If worms perform one or both of these functions for tortoises, then they may actually be helpful, at least so long as they don't become too numerous and start to take a toll on their host.

So, this is what I mean when I say that characterizing worms as parasites may be too simplistic. Not entirely wrong, but perhaps not completely right, either. There may be more to it than that.

 

[EricIvins]

My only thought is that they aren't treated for parasites in the wild and still manage. However, in captivity, are they missing something that does not keep them in check, that they are getting in the wild? Hmmmm

It's called stress.......

Tortoises, and any other Reptile for that matter do well with high Parasite loads. Their Immune systems cycle them out and they have no issues.

I for one will not treat any animal unless their is an obvious issue. It doesn't do anything for the animal to pump them full of Poisons and Anti-biotics in a half hearted attempt to elimate Parasites.......

Proper de-parasitation takes 6+ months, with Fecals just about daily, and a multitude of medications to actually "worm" a Reptile. Give the animal 4 months of stress free proper husbandry, and the animals immune system just did all that work for you..........

It's a simple concept really, but unfortunately most don't get it. They'll continue with the typical Panacur and Flagyl shotgun treatment in hopes that it will work. De-parasitation needs to be strategic, not full spectrum.......

 

[StudentoftheReptile]

Since my response was dismissed as semantics, please enlighten me with an explanation of how a parasitic worm, which lives off of the blood of the host is a benefit to the host.Does it help get rid of all that pesky extra blood? Your explanation of symbiotic bacteria has nothing to do with parasites.

Well, I was not dismissing your response. I was simply pointing out that our view of worms and other organisms is changing, such that it may no longer be adequate to consider them only as parasites anymore. Anyway yes, I will be happy to go into more detail.

1) Immune response - There is evidence that certain antibodies (IgE), which cause allergies in humans and other mammals, originally evolved as a defense against parasitic worms. In addition, worms appear to release enzymes into their host's body to modulate its immune response. When worms are present in small numbers, the host's immune system appears to be regulated such that inflammation decreases, reducing the likelihood of chronic autoimmune diseases like allergy and bowel irritability. In this scenario, although worms can harm their host if present in large numbers, the host has evolved to maintain small populations of worms in the gut. This is known as the "old friends hypothesis," and it basically just means that, although worms are parasites, mammals may actually need them to help maintain a healthy immune system. This might apply to reptiles, too.

2) Digestion - Plants are hard to digest, so herbivores have evolved ways to help break them down so they can be used as nourishment. In mammals, this begins with thorough chewing by molar teeth to greatly increase surface area, so that enzymes can have access to the plant fibers and degrade them. However, because vertebrates do not produce their own cellulose-degrading enzymes, they rely on symbionts living in their gut, like bacteria, to produce these enzymes for them. In addition, mammalian herbivores have evolved very long gastrointestinal tracts to retain plant matter for long periods (up to a few days), so that it can be broken down and absorbed. Herbivorous reptiles like tortoises may have longer guts than their carnivorous cousins, but they are much shorter than those of herbivorous mammals like cows and horses, both in absolute and relative terms. Also, tortoises don't chew their food, and they don't necessarily swallow stones for gastroliths, either. So maybe tortoises need help digesting all that plant matter. One possible way for that to happen is nematode worms, which may help out in two ways. One, some nematodes can produce cellulolytic enzymes, the way bacteria do, to help break down plant matter. Two, the movement of nematodes may help churn the food bolus in the gut, increasing its surface area and speeding up its rate of digestion. If worms perform one or both of these functions for tortoises, then they may actually be helpful, at least so long as they don't become too numerous and start to take a toll on their host.

So, this is what I mean when I say that characterizing worms as parasites may be too simplistic. Not entirely wrong, but perhaps not completely right, either. There may be more to it than that.

Right on, and what a great topic!

Probably the one thing I actually learned in a parasitology course during my brief stint as a biology major in college before turning to the arts was...indeed what Geo said, that worms as "parasites" was just a matter of semantics. Whenever the layperson hears of worms or bacteria dwelling within the digestive tract of an animal, they automatically think its some parasitic organism sucking the life essence of their pet. But there are indeed many types of "parasites;" many are simply benign, some are beneficial, and astonishingly very few are a real cause for alarm.

For years, I was the same way. For any new arrival herps in my collection, it was off to the vet for a check-up and a deworming, and I often suggested others to do likewise if they really cared for their pets. But I soon discovered that sometimes a deworming is unnecessary in many cases, as Eric pointed out.

 

[jkingler]

'Old friends' has always made a lot of sense to me, and re: humans, it makes more and more sense as more and more science comes out (and there is already a lot of science that backs it up, last I checked).

Regarding tortoises and their natural ways of 'deworming' themselves...:
My only thought is that they aren't treated for parasites in the wild and still manage. However, in captivity, are they missing something that does not keep them in check, that they are getting in the wild? Hmmmm
As stated by others, the lifespan of tortoises vs. parasites and the very potent plants that tortoises eat in the wild are probably a factor. But I was wondering (and pardon my bit of uninformed theory): in much the same way that diatomaceous earth kills bugs, could ingesting sand/dirt/gravel/rocks etc perhaps be purposefully done to reproduce a similar effect? Just a thought...

 

[GeoTerraTestudo]

'Old friends' has always made a lot of sense to me, and re: humans, it makes more and more sense as more and more science comes out (and there is already a lot of science that backs it up, last I checked).

Regarding tortoises and their natural ways of 'deworming' themselves...:
My only thought is that they aren't treated for parasites in the wild and still manage. However, in captivity, are they missing something that does not keep them in check, that they are getting in the wild? Hmmmm
As stated by others, the lifespan of tortoises vs. parasites and the very potent plants that tortoises eat in the wild are probably a factor. But I was wondering (and pardon my bit of uninformed theory): in much the same way that diatomaceous earth kills bugs, could ingesting sand/dirt/gravel/rocks etc perhaps be purposefully done to reproduce a similar effect? Just a thought...

Yes, that is a fair point. We can't assume that tortoises will be able to handle worms in captivity the way they do in the wild. So, yes, intervention may become necessary at some point. However, like Student, I doubt if prophylactic de-worming is desirable. If problems arise, then we can deal with them. But as long as our tortoises have a good home and a good diet, they should be able to tolerate the worms in their gut the way wild tortoises do, and might even benefit from them if we just leave them there.

 

[Neltharion]

So, this is what I mean when I say that characterizing worms as parasites may be too simplistic. Not entirely wrong, but perhaps not completely right, either. There may be more to it than that.

The biological term for a mutual beneficial relationship would be Mutualism-Both organisms benefit.

The term for a relationship where one organism benefits but the other is relatively unaffected would be Commensalism-A form of symbiosis between two organisms of different species in which one of them benefits from the association whereas the other is largely unaffected or not significantly harmed or benefiting from the relationship.

I remember reading about zoopharmacognosy in Russian tortoises, where they would eat extremely bitter or small amounts of mildly toxic plants to self-regulate their gutloads of worms and other micro-organisms. I don't recall exactly where that article was. There is a general article with a section about animals that self-medicate at: http://www.carecentre.org.za/medicinal.htm.

Based on that, I tend to believe that the statement that animals in the wild aren't treated for parasites isn' entirely true. I agree to the notion that they are able to self-regulate by eating certain plants. Of course in captivity they don't have access to these plants. I've never dewormed just for the sake of deworming. I have dewormed in a few instances where there was obviously something wrong (large number of worms in the stool, runny stool, tortoise was losing weight, or tortoise not eating). I agree with the statements that a healthy animal that isn't stressed, and kept in correct conditions will generally not need to be dewormed.

 

[GeoTerraTestudo]

So, this is what I mean when I say that characterizing worms as parasites may be too simplistic. Not entirely wrong, but perhaps not completely right, either. There may be more to it than that.

The biological term for a mutual beneficial relationship would be Mutualism-Both organisms benefit.

The term for a relationship where one organism benefits but the other is relatively unaffected would be Commensalism-A form of symbiosis between two organisms of different species in which one of them benefits from the association whereas the other is largely unaffected or not significantly harmed or benefiting from the relationship.

I remember reading about zoopharmacognosy in Russian tortoises, where they would eat extremely bitter or small amounts of mildly toxic plants to self-regulate their gutloads of worms and other micro-organisms. I don't recall exactly where that article was. There is a general article with a section about animals that self-medicate at: http://www.carecentre.org.za/medicinal.htm.

Based on that, I tend to believe that the statement that animals in the wild aren't treated for parasites isn' entirely true. I agree to the notion that they are able to self-regulate by eating certain plants. Of course in captivity they don't have access to these plants. I've never dewormed just for the sake of deworming. I have dewormed in a few instances where there was obviously something wrong (large number of worms in the stool, runny stool, tortoise was losing weight, or tortoise not eating). I agree with the statements that a healthy animal that isn't stressed, and kept in correct conditions will generally not need to be dewormed.

I'm not prepared to call the symbiosis between tortoises and nematodes a mutualism or a commensalism yet. It seems that in large numbers, nematodes are indeed parasitic and gradually harm their host while they benefit. However, in small numbers, they seem mutualistic, with both the host and the symbiont benefiting. I don't think there is a term yet for that kind of a relationship, where the same organism can be either good or bad, depending on how many of them there are. Maybe we could coin a new term here. How about paramutualism?

 

[Kristina]

In captive tortoises, parasites can become a problem for various reasons - overcrowding, less than ideal husbandry, and stress.

I don't routinely worm my tortoises. I do worm those that I know are fresh imports, just because they are already dealing with the stress of acclimation, and usually starvation and dehydration as well. On a tortoise that I newly purchase (with the exception of 2 week old captive bred babies, lol) I perform a fecal exam and only worm if there is an OVERABUNDANCE of parasites present.

I agree that some parasites in the guts are normal. We just have to make sure that it doesn't reach infestational proportions.

 

[Laura]

Parasites and Bacteria in the gut are two different things.. de worming and treatment with antibiotics can kill the bacteria and the use of Probiotics might be a good idea...
In the case of rabbits.. if you treat with certain types of Antibiotics.. you kill gut bacteria.. then.killing the rabbit. They NEED it to survive..

 

[Kristina]

Yup. That is why when I bottle feed a baby rabbit, I actually add the feces of a healthy adult to the formula.

I also have fed the feces of a healthy tortoise to a sick or ailing tortoise.

 

[GeoTerraTestudo]

Yup. That is why when I bottle feed a baby rabbit, I actually add the feces of a healthy adult to the formula.

I also have fed the feces of a healthy tortoise to a sick or ailing tortoise.

Nice. Fecal transplant is being done experimentally in humans now, and with success, too. Chronic disorders like irritable bowel syndrome can disappear with fecal transplant, so it makes sense that it would work in other animals, like tortoises, too.

 

[HLogic]

Terms to research:

Normal [intestinal] flora
Opportunistic infection/infestation
Obligate parasite