Step right up! Behold a Two-headed Snake!

Clients of mine who breed corn snakes recently had this very unusual baby hatch out of an egg in their incubator, a two headed snake! The hatchling appears to be a pair of conjoined twins which is very rare indeed. We occasionally see two-headed snakes hatching and it is usually a random event; a freak coincidence causing fusion during early embryonic development known as polycephaly.

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In any case, most two headed snakes look to all intents and purposes like a single snake body with two heads side by side on a single neck. This hatchling however is conjoined much farther down the body, just above the level of the heart so it appears from X-rays I took that each head has a separate throat, windpipe (or trachea) and oesophagus that carries food to the stomach. This most likely resulted from fusion of monozygotic or identical twins during the early stages of development within the egg. It was extremely difficult considering the tiny size of the creature to obtain good diagnostic quality X-rays especially as the animal was conscious and difficult to keep it still to take a shot, so the exact anatomy is still unclear. I didn’t want to risk anaesthetising such a fragile, tiny creature just for interest sake to look at its anatomy but from what I can make out it seems like there is one dominant animal with relatively normal anatomy and the other has fused just above the level of the heart. I think there is a single heart, stomach and other abdominal organs, although there is a lot of air so there may be two lung spaces, unusual in that snakes usually only have a single functional lung.

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Other problems that are evident are that the spine is kinked in a few places, which may cause problems down the line, although plenty of minor kinked snakes do lead perfectly normal and pain free lives. The good news is that the little snake has now eaten its first meal, and appears to be doing well. Whether it survives long term is still unknown however. There could be invisible problems we are not yet aware of. If it does survive it would be very interesting to perform more advanced imaging such as MRI to determine the anatomy, but of course this is all academic as there would be no benefit to this little snake, or should I say snakes! Surgical correction is not possible and would result in the death of one or both animals. The main concern in the near future is whether quality of life can be maintained.

More information on the underlying causes can be found here:

http://genetics.thetech.org/ask/ask299

http://news.nationalgeographic.com/news/2002/03/0318_0319_twoheadsnake.html

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Reptile Keeping: 9 Signs You’re Doing It Wrong!

  1. You feed your leopard geckos an exclusive mealworm diet, from a bowl, with a separate dish of calcium powder. Groan…..

2. You have no idea where in the world your animal originates, or what it’s actual habitat looks like.

 

3. Your reptile keeping inspirations are certain US ‘big breeder’ YouTube sensations who stack ’em high, & rack ’em wide!

 

4. Your stock answer to the question “What temperature are you keeping them at?” is: “It has a 60W bulb”.

 

5. You believe that sand causes impaction, and not that sand impaction is a symptom of poor husbandry and/or nutrition.

 

6. You ask for advice for an urgent medical condition your pet reptile is suffering from on 7 Facebook forums, 5 local petshops, 3 breeders you know, 1 vet you know through Facebook (ahem!) and your mate down the pub…..before finally booking a vet appointment 2 weeks later.

7. You are breeding normal Bearded Dragons currently in the UK despite a massive overpopulation and welfare problem with unwanted Beardies.

Baby bearded dragons

 

8. You buy or ‘rescue’ reptiles without researching them, then ask other people how that species are best cared for or what medical care it needs (that you can’t afford) now you’ve taken it from the previous owners.

 

9. You don’t recognise the difference between an animal surviving Vs thriving, and continue to defend old school husbandry practices like withholding UV lighting from species that are exposed to it in the wild.

Can you see my heart beating? A snake with a very big problem!

Snake transport box

I received an unusual phone call recently from the owner of an 18 month old False Water Cobra (Hydrodynastes gigas), a South American rear-fanged, mildly venomous species of snake (http://www.reptilesmagazine.com/Snake-Species/False-Water-Cobra/). The owner had noticed shortly after acquiring the snake that it had what was described as a wound on it’s underside through which you could see it’s insides! Naturally, I was quite worried so asked for the snake to be brought in for examination, and in the meantime they emailed me some photos and reassurance that the snake was acting perfectly normally, eating and defaecating fine and didn’t seem in any way bothered by the strange ‘wound’.

False Water Cobra Hospital Vivarium on AdmissionFalse Water Cobra Hospital Vivarium on Admission 1

Having examined the animal, it appeared that she had a defect in the body wall on her ventral surface or belly with a large hole visible in the ventral muscles. Bizarrely, this defect was at the level of the heart about a third of her length down her body. The only tissue separating her visibly beating heart from the outside world was a thin membranous layer of body cavity lining and some connective tissue which was quite transparent. I have seen some similar lesions in reptiles at the umbilicus or site where the blood vessels carry nutrients into the growing embryo from the egg or from maternal tissues in the case of live bearing species. Sometimes when these animals hatch or are born the hole in the body wall fails to close completely and an umbilical hernia or body wall defect is left behind. However, I have never seen or even heard of such a defect high up on the body overlying the heart! I concluded that this must be a congenital problem that the snake was born with, perhaps a fluke genetic mutation or a developmental insult during incubation of the egg which disrupted the normal growth of the embryo resulting in a physical abnormality at birth. Having spoken to a few reptile enthusiasts in the UK who keep this species of snake, it turns out there have been a few reported with the exact same defect in the exact same place, so it looks likely this is a genetic problem, most likely caused by inbreeding in certain lines due to relatively low genetic diversity in the UK population.

Snake membranous hernia before surgery

The risk of leaving the snake in this condition was that during the course of her life she may snag this fragile membrane protecting her heart and eviscerate herself or worse still puncture her heart. Although this risk was small, it would be safer to carry out a surgery now than always wonder and worry if she might do some damage and seriously injure herself, when pulling off her shed skin for example. I admitted her and set her up in our reptile ward in a heated vivarium to bring her body temperature up to preferred range. Once her temperature was correct I injected her with a combination of sedative drugs into the muscle in her back. I say I injected her, but actually I restrained her with a thick pair of gloves whilst my nurse Justyna gave her the injection. She was very feisty, strong, and objected to restraint, trying to bite the gloves. Obviously considering her potential to give a painful bite and possible envenomation we took great care at this stage. Rear fanged snakes are different to other venomous species in that they have modified salivary glands and teeth at the back of their mouth, with which they chew their prey in order to inject and subdue it. Therefore it would be difficult to get a dangerous bite  from a rear fanged species unless you allowed the snake to chew on you. Front fanged species can deliver a dry or wet bite from the front of the mouth with a rapid strike and minimal contact so are far more dangerous to work with and handle. After her injection we left her back in her hospital vivarium in the correct temperature to allow her to metabolise the drugs efficiently. Ectothermic or ‘cold-blooded’ animals such as reptiles rely on external temperature to control their biological functions and metabolic rate, so it is vital when treating ill specimens and indeed when undertaking anaesthesia and surgery to maintain their body temperature in the correct range so everything runs smoothly and drug dosages work effectively. After about a 20-30 minute induction period, now nice and relaxed after her sedation we removed her and placed her into an anaesthetic gas chamber so she fell further asleep and we could position and prepare her for surgery. She was maintained under anaesthesia by using a gas mask delivering a safe gaseous drug called Sevoflurane. Normally for a prolonged surgical procedure in a snake I would intubate the animal with a solid plastic or rubber tube placed into the windpipe or trachea for better control and access to her airway should she stop breathing for instance, but in the case of venomous species I prefer not to mess around in the mouth due to the risk of accidental envenomation. A correct sized mask with her head taped inside in place and sealing the entrance provides the next best option and is safer for all involved.

Snake anaesthesia preparing for surgery

 

Here’s a video link showing the heart visibly beating underneath the membranous layer of the abdominal wall defect:

Once Justyna prepped her with a surgical scrub and insulating layers to maintain her body temperature lying belly up on a surgical heat mat, I was ready to begin. I carefully dissected away the thin membrane covering her heart from the scales on either side of the deficit. I had to be extremely careful as this layer of tissue was so thin and the heart was literally beating against it directly underneath. Tiny blades and scissors were required, and I cut in time between the beats to avoid cutting at the moment the heart filled to maximum capacity with blood. Myself, Justyna and the veterinary student who is seeing practice with us this week to learn more about exotic pet medicine were all holding our breaths at times. Credit to the student Conor for taking the photographs while I operated by the way. Justyna found this anaesthetic very easy to monitor throughout as we were literally watching the heart beating throughout so she could record heart rate and strength with the naked eye for a change! Often we use sensitive probes to monitor heart rate through the body wall but not needed in this case.

And here is a video during the surgery when I had carefully dissected away the thin tissue revealing the heart beating underneath before I began to suture the defect closed:

Once the tissue had been separated away from the half sized scales lining either side of the lesion I set about suturing the hole back together, bringing the soft tissue of the internal body wall and the edges of the scales together to meet in the middle and form a tight seal which would heal and protect the heart and blood vessels underneath. I was quite happy with a neat and tidy job at the end. She was given a long acting pain medication and anti-inflammatory by injection, and a reversal drug for the sedatives given earlier and placed back in a clean dry cage with paper substrate to recover. We turned up the heat temporarily to boost her metabolic rate and aid her clearance of the anaesthetic drugs, and within 20 minutes she was groggy but wandering around her cage getting her bearings again. It always surprises me how tough these animals are. Reptiles have been around for millions of years and they really are quite resilient and remarkable in what they can withstand. Many of my clients fret and worry about anaesthetic risk in particular if their pet reptile needs a surgery for example. Although the general risk is higher than in dogs and cats I find them to be remarkably sturdy anaesthetic patients for the most part, so the risk is still quite low as long as you seek out an experienced and knowledgeable reptile vet.

Snake repair after closure

 

In terms of aftercare, she just needs to be kept clean and dry. No antibiotics were prescribed as it was a sterile op and good hygiene practices should prevent infection from here. Being a semi-aquatic species that likes to bathe in water, I’ve specified that she is not allowed a water dish in which she could submerge as the wound could act as an entry point for water and bacteria or other contamination into the body cavity if she submerged in the coming week or so. I will keep her in overnight and send her home tomorrow. So far she is making an excellent recovery. The sutures I placed are dissolvable over time and should slough off the next time she sheds her skin or possibly after that, so I just need to recheck her in a week to make sure the wound looks good, is healing well and is free of infection. Problem solved!

Snake in recovery

Metabolic Bone Disease: Another Rubber Tortoise!

WARNING: THE VIDEO AT THE END OF THIS ARTICLE IS DISTRESSING AND FEATURES A DEAD ANIMAL IN A POOR PHYSICAL STATE. PLEASE WATCH AT YOUR DISCRETION.

Virtually every week I am presented with a pet reptile which has an advanced disease relating to poor owner preparation or knowledge on how to keep these specialist animals. Today I had a tortoise patient booked in as a health check, but knew instantly on taking it out of it’s container that I would be humanely putting it to sleep as it had been suffering for a long time from metabolic bone disease (MBD) relating to poor husbandry and nutrition. I am angry, frustrated and weary of having to destroy animals that can be kept very successfully in captivity with a little bit of preparation, initial outlay of financial investment, research and common sense. I am astounded that I am having the same conversations over and over again with reptile owners who really don;t know how to keep the animals in their care, but have taken someone else’s word for it without doing extensive research of their own. I will explain what led to this animal’s demise, and how it could have been prevented. I hope this post gets shared widely as the owner has kindly agreed I can share the story so that other owners may be educated and welfare improves for at least some animals as a result. I have to commend the owner of this tortoise for at least bringing the tortoise to the vet. I’m sure many don’t and their animal dies slowly at home. My role as a vet is to educate owners and safeguard animal welfare, often having to be quite diplomatic in the face of pretty distressing cases of animal suffering. I recognise the tone of this post comes across as an angry rant, but I need to drum home an important message in the hopes I help some new keepers revise the care they are providing to their pet reptile and correct any issues before they cause such suffering as I saw today. Firstly, before I get to the details of this case let me explain a little about metabolic bone disease (MBD).

MBD is a condition whereby an animal lacking in calcium, ultraviolet (UV) light exposure or both eventually becomes so deficient that it starts to absorb calcium from it’s skeleton and in the case of turtles and tortoises, it’s shell, in order to maintain normal metabolic function. Calcium is required for a variety of bodily functions including skeletal growth, neurological activity, muscle contractions and hormonal control for example. Reptiles in captivity are particularly vulnerable to MBD as they are reliant on their owners to provide them with artificial UV lighting, replication of a varied and natural diet, as well as appropriate calcium and other vitamin/mineral supplementation. The absorption of UVB light from natural sunlight allows reptiles to synthesise Vitamin D3 in their skin, and vitamin D3 allows them then to absorb calcium from their diet in the gut. This delicate balance between sunlight, vitamin D and dietary calcium sources is reliant on environmental temperatures, and is hindered if reptiles are kept in conditions which are colder than their preferred optimal temperature zone (POTZ). So you can appreciate that there is a fine balance between several interlinked factors that could contribute to the development of MBD when we take reptiles into captivity and take control of their immediate environment. Temperature, lighting and diet are the three factors that lead to the development of MBD. Get any one of those factors incorrect and you are setting your animal up for ill health. For further reading on this topic I can highly recommend reading the following book from leading reptile lighting specialists Arcadia: (www.arcadia-reptile.com/mbd-book-reviews/).

The basis of keeping any reptile as a pet is very simple. I will share this basic ‘secret’ now. It is not rocket science. It is very simple and achievable. Although it is often inconvenient or more expensive than some people are prepared to pay. And it is not often achieved by taking shortcuts or following some pet shop’s or online forum’s advice. The simple rule of reptile keeping is this:

REPLICATE THEIR NATURAL CONDITIONS IN THE WILD!

Sounds easy, right? Well it is. But unfortunately there are a multitude of sources of information giving conflicting advice, a bewildering array of equipment and housing options commercially available, and an unfortunate trend in the reptile hobby of keeping animals in conditions which allow them to survive with minimal effort or expense. The aim of keeping reptiles as pets should be to provide them everything they need to allow them to thrive and flourish in as near natural conditions as possible, not just to survive with the minimum provisions they need. It is not up to the pet shop staff to give you the right equipment. It is not up to the guy on some forum who told you how to keep your pet alive. It is up to YOU to research the conditions your animal comes from in the wild, and how best to replicate them in captivity. There is no one perfect list or care sheet that does this work for you. Different keepers do things different ways. What you need to research is what temperature, humidity, diet and light your animal needs and then ensure you are providing that by monitoring the conditions in your particular set up. Just because someone does it their specific way and has had success, doesn’t mean you will achieve the same in your particular setup by following their lead. There are many variables that might affect your animal’s long term health.

I have lost count of the amount of times I ask someone the question: “What temperature is your vivarium?” and am met with the reply “I don’t know, it’s warm”. A thermometer so you can record and monitor the temperature, and a thermostat to control the temperature are two vital pieces of equipment for providing the correct environment. A thermometer costs very little, a thermostat significantly more. But without them how do you know you are providing the animal with the correct range of temperatures it needs to survive? YOU DON’T! So you could be providing sub optimal temperatures sometimes or overheating your animal at others, resulting in biological stress and impaired immunity or overall health. If you have no thermostatic control of your vivarium, then the temperatures will fluctuate depending on conditions outside the vivarium in the room for example. Hence why advice telling you a specific wattage of bulb is suitable for a certain species is far too vague, as it doesn’t take into account how cold or warm the room in which the vivarium is housed tends to be. Rather, good advice should tell you the correct temperature  range for your species, and it is up to you to find the correct bulb or other heating to achieve that temperature range that allows natural thermoregulation. UV lighting needs to be the correct intensity for the species of reptile being kept, needs to give enough exposure to UV rays by it’s spread and location in the enclosure and needs to be replaced frequently to maintain high enough levels in the enclosure. These bulbs also cost money. Diet needs to be researched. Convenient options often lead to long term problems. It takes time and significant effort, as well as significant expense, to provide a varied and natural diet. If you are not willing to invest this time, research, effort and expense into keeping a pet reptile, DO NOT BUY ONE!

The reptile hobby as it stands is under increasing pressure from animal rights and welfare lobbyists arguing that these animals should not be kept in captivity at all due to the significant welfare problems they experience and the relatively high (often over exaggerated) mortality rates. I know many wonderful, knowledgeable and extremely capable reptile keepers as friends and as clients who provide amazing care to the animals they look after. However, there is a massive welfare problem with captive reptiles which cannot be ignored. I see it in my line of work very frequently that beginner or inexperienced keepers are making very costly husbandry or nutrition mistakes which are costing the lives of a huge number of animals up and down the country every day. As a hobby, we are defensive when criticised by animal rights groups, but to ignore that there are huge welfare problems in the hobby is actually doing ourselves a disservice.

Anyway, back to the tortoise I had to euthanise today. It was only a year and a half old and had been purchased from someone online. It had been kept in a vivarium with a single combined UV and heat lamp as the sole heat source. The owner didn’t know what temperatures were being provided. There was no thermostat. The pet shop staff told the owner that bulb was suitable for tortoises. The bulb had not been changed for well over a year. The tortoise was fed commercial tortoise pellets from a large plastic tub as it’s staple diet. It also ate lettuce and cucumber. No calcium, multivitamin or mineral supplements were provided. The owner noticed it’s shell was ‘looking weird’ around Christmas time. Today is the last day of March. It was brought in today because it had stopped eating. It had also stopped moving very much. It’s shell was very flat and very soft. TORTOISES SHOULD NOT HAVE SOFT SHELLS! IF THEY DO, YOU’VE BEEN DOING IT WRONG! Why are we still seeing cases where reptile owner’s are doing it so wrong?

Here’s my take on the above husbandry failings. You should research tortoise or any pet’s care long before you buy one. You should have read all available information, and asked as many questions as you can of experienced keepers until you are an expert on their care. Clear up any confusion you have before you purchase an animal. Don’t just listen to one point of view. Explore the theory, and examine the logic behind the varied advice you are given. Steer clear of prescriptive advice that tells you ‘X species needs Y type of bulb’. REPTILE HUSBANDRY IS NOT THAT SIMPLE!

Mediterranean tortoises do best in large open topped well ventilated enclosures such as ‘tortoise tables’. Vivaria can lead to problems with temperature and humidity for Mediterranean tortoises. A single combination UV and heat bulb may work for some keepers who have mastered the pretty simple task of knowing and controlling the temperature correctly using a thermometer and thermostat, selecting the correct wattage bulb for their set up and providing a nutritious, appropriate captive diet with correct supplementation. It does not work for everyone, and I would argue that pet shops should not be selling these bulbs for beginners to keeping tortoises as these are the owners who are likely to get other factors such as diet wrong too. A preferable option is to provide a heat lamp and a separate UVB fluorescent tube which covers the entire length of the enclosure. That way the tortoise will receive UV light throughout the entire enclosure, even when it is not basking directly under the heat lamp. Tortoises do not bask in the one spot for long periods, they roam. By choosing a combination bulb your tortoise may not receive the optimal level of UVB exposure over time and therefore if your temperatures and diet are also somewhat deficient your tortoise will not thrive. It may even develop metabolic bone disease. Remember the intricate relationship between temperature, lighting and dietary balance? Take any one of those factors out or skimp on their provision and you are setting yourself up for a case of entirely avoidable MBD, among other potential health problems. If you do not know the temperature you are keeping your reptile at, buy a thermometer and find out. Pretty simple concept. If the temperature fluctuates widely in your specific set up due to external factors then buy a thermostat and make sure it is controlled. Yes, that costs money. If you can’t afford one, maybe you can’t afford a reptile. If you can’t afford one for your newest reptile, maybe you have too many reptiles. NOT KNOWING WHAT TEMPERATURE YOU KEEP YOUR PET REPTILE AT IS A COMPLETE NEGLIGENCE AS A PET OWNER.

UV lighting needs to be changed on a regular basis. The bulbs give out light for long periods, but the output of the UV spectrum of light declines with time, generally over the course of 6-12 months depending on the manufacturer and quality of the bulb. Document when you buy new bulbs and when they need to be replaced. Young, actively growing reptiles in particular with high calcium demands cannot do well with a sub optimal level of UV light, even for short periods without suffering.  Commercial pelleted foods are not a staple diet, they are a supplement to a healthy diet. Their nutritional content declines with time. They may be convenient for the owner as they sit in a tub ready to be poured into a feeding bowl, but tortoises need a variety of fresh greens, weeds, grasses, flowers and small amount of vegetables to thrive. Dry pelleted food is not a substitute for a fresh diet. Diets also need to be supplemented with calcium, and other vitamins and minerals that may be lacking in the limited diet we invariably provide in captivity. Lettuce, cucumber and tomato is an extremely poor diet as it has a high water content but very few valuable nutrients. As an aside which is unrelated to this case, I hear from time time time about the act of feeding tortoises dog and cat food. NEVER FEED ANIMAL PROTEIN TO HERBIVOROUS MEDITERRANEAN TORTOISES. (Jam sandwiches or chips are also off the list. I’m not joking!).

If you notice your tortoise or other reptile pet acting or looking strange, then BRING IT TO THE VET! Don’t wait until it can’t move or no longer eats. Don’t wait until you’ve read a few articles and self diagnosed it, then tried to treat it at home. Don’t ask other hobbyists on five separate internet forums until you hear get the answer you want or whatever other DIY home treatment option you might try first. IF YOU CANNOT AFFORD VETERINARY FEES, YOU CANNOT AFFORD THE PET! Reptiles hide illness very well to avoid predation int he wild. If you think they are sick, they are probably sick. Seek a qualified and experienced reptile vet at the earliest opportunity and work with them. Don’t lie to them or withhold important information that could aid their diagnosis (this happens a lot too, though not in this case). A deformed or misshapen shell in tortoises and turtles is always indicative of a problem. If the shell is softening this problem is advanced.

This tortoise today had a softened, flattened shell like a rubber ball. This did not happen overnight. The owner noticed at Christmas that something was wrong. But only brought it in to my clinic when it had stopped eating and stopped moving. The tortoise was so deficient in calcium over a long period of time due to poor heating, poor lighting and poor diet that it had absorbed it’s shell and skeleton of calcium, thus softening the bones to the point they could no longer support it’s body weight. It was undoubtedly in immense pain. It was having to pull it’s forelimbs back and forth to try to keep breathing as it’s collapsed rubbery shell was compressing it’s lungs and causing respiratory distress. It was undoubtedly in multi-systemic organ failure at the tender age of 18 months. It had the potential to outlive it’s owner, it’s owners children and potentially grandchildren if a little more research and effort had gone into it’s care. Sadly, it was beyond help, and I have to take comfort in the fact I could relieve it’s suffering and put it out of it’s misery humanely. I am however, still angry, jaded, frustrated and tired of seeing this problem crop up over and over again whilst trying to maintain an upbeat, positive demeanour that will help educate the owner rather than turn them against the idea of veterinary care.

Below is the video of the tortoise which may be distressing to some people. Please view at your discretion. Please also note that I took this video AFTER the tortoise had died, so it is no longer suffering. It is explicit to show the extreme changes that can occur with MBD as a direct result of poor husbandry and nutrition. If it makes one person improve the care of their pet tortoise it will be worth posting, so please feel free to share this article.

Luxury Digs! What your ‘garden tortoise’ really needs…

Mediterranean tortoises are rousing from hibernation this time of year, and really need conditions to be correct in order to thrive and return to good health following a long period of fasting and dormancy over winter. The critical factors which must be provided correctly to ensure they return to good health and begin eating promptly after waking are provision of appropriate heating and lighting. If keeping them outdoors in the garden straight away after waking from hibernation, they really are at the mercy of the British weather; often too cold and too wet to kick start their metabolic rate which is heavily reliant on external temperature. If tortoises don’t receive the correct heating and UV lighting in this critical period, they often fail to regain appetite, immunity declines, they can become dehydrated and burn off even more of their already depleted energy reserves leaving them prone to infections and organ dysfunction, failure or even death. It is therefore critical that supplemental heating and lighting is provided with a heat lamp and UV light for any period when the British weather is poor, but especially so in the immediate post hibernation period in Spring.

Last weekend I had a post hibernation check in a lovely 30 year old Spur-thigh tortoise named Mr Slow. He was the picture of health, and his very caring owner had commissioned her handy neighbour to build him a state of the art tortoise house in the garden which catered to all of his needs mentioned above. As you can see from the photos below, he has a beautiful house with thermostatically controlled, weather proof porch leading to a covered sleeping area. He has a combined heat and UVB lamp under which to bask which is on a timer, and a special UVB penetrating Perspex sunroof for natural sunlight exposure even on cold days. A ramp leads to the enclosed escape-proof garden for when it is warmer and he wants to  head off and explore! Luxury digs indeed…..

Tortoise House 1Tortoise House 3Tortoise House 2 Tortoise House 4

 

More info on tortoise hibernation, overwintering and post hibernation problems in my previous blog posts here:

https://exoticpetvetblog.wordpress.com/2015/02/20/post-hibernation-problems-in-tortoises/

https://exoticpetvetblog.wordpress.com/2014/10/07/163/

Thiamine (Vitamin B1) Deficiency in Garter Snakes

Neurological garter snake

Neurological garter snake

This week I was presented with a sub-adult red-sided garter snake (Thamnophis sirtalis infernalis), a North American species of snake which feeds primarily on fish and amphibians in the wild. In captivity these snakes are often fed on fresh or defrosted fish, as well as earthworms, live goldfish or other feeder fish such as minnows or guppies, and pinkies or baby mice.

The snake had suddenly shown a minor head tilt and by the following day was found turning upside down unable to right itself. The owner who is quite knowledgeable on reptiles brought it down immediately for me to examine as timing is of the essence in treating reptile patients. Often they hide signs of illness until a disease is quite advanced, due to being prey species in the wild, so the owner recognised the urgency of seeking veterinary treatment.

The most common differential or suspected diagnosis for a presentation such as this, a garter snake with neurological signs, is a thiamine (Vitamin B1) deficiency associated with captive diet provision.  A deficiency in this vitamin leads to inflammation and destruction of cells in the central nervous system resulting in symptoms such as head tilt or wobble, torticollis (twisting of the neck), opisthotonus (stargazing), nervous tremors, incoordination, convulsions, apparent blindness and death.

In the video link below on my Facebook account you can see how the snake was off balance and incoordinated, as well as ‘stargazing’ or throwing it’s head back over it’s body to the sky:

The issue with captive diets is that they often rely heavily on a single, readily available species of fish. Many fish species, both freshwater and saltwater, contain an enzyme called thiaminase which degrades thiamine or vitamin B1 from the diet. If such species are fed over long periods a deficiency in this vitamin occurs causing the clinical signs outlined above. There is some confusion as to the role of freezing and defrosting fish to feed to garter and other piscivorous or fish-eating snakes such as the water snakes (Nerodia spp.) as well as freshwater turtles and terrapins that rely heavily on fish based diets. In certain species of fish the naturally occurring thiaminases in the flesh are not destroyed by freezing, therefore when they are fed exclusively the thiamine in the diet is depleted and deficiencies occur. Some loss of thiamine in frozen defrosted fish can be prevented by defrosting the fish in hot water (80C for 5 minutes) which denatures the enzyme, although this has some disadvantages in that it can reduce the nutritional value of the food further. Some owners will add a vitamin B1 supplement to the food to counteract the depletion of thiamine. However, the best option for feeding fish to piscivorous reptiles is to feed fish species which have very little or no thiaminase enzyme in the first place. Many readily available and traditional food choices for garter snakes are poor choices due to their thiaminase content, feeder goldfish being a perfect example. Goldfish actually contain high levels of thiaminase despite being the most widely available feeder fish and most widely recommended for garter snake food!

The owner of the snake I treated this week fed frozen defrost Smelt to her garter snakes, along with fresh trout and salmon. All of her garter snakes were very healthy and thriving on this diet so there was some confusion and disappointment as to why I thought this one had succumbed to hypovitaminosis B1. It turned out that this particular animal was quite a fussy feeder compared to the other individuals and rarely accepted a meal of trout or salmon, but rather fed almost exclusively on the defrosted Smelt. Smelt is a readily available frozen feeder fish, which contains relatively low levels of thiaminase compared with many other sources such as mackerel, goldfish or whitebait, but if fed exclusively for long periods can result in the thiamine or B1 deficiency over time. My plan for treatment was to administer high dose injections of Vitamin B1 and monitor the response to treatment. A positive response to treatment with reversal of the clinical signs confirms the diagnosis in these cases. I gave two injections 3 days apart, the second of which was today and already the little snake is doing much better; more alert, responsive with normal coordination and mobility, and no longer twisting or flipping over. Only a very mild head tilt remained, which I anticipate will have disappeared once it comes back at the end of the week for the last vitamin injection. In severe or advanced cases the neurological damage can be too severe that the central nervous system particularly the cerebral cortex of the brain becomes necrotic and the animal fails to recover. Luckily in this case the vigilant owner brought the patient in in time to save it.

Garter snake recovered and moving normally

Garter snake recovered and moving normally

In future, I recommended Smelt should only be used as an occasional convenient source of food, not as a regular component of the diet. The owner will have to make efforts to introduce more variety into the snakes diet with earthworms, pink mice, feeder fish species that lack the thiaminase enzyme such as guppies and platies, or commercially available fresh and frozen fish species again that lack thiaminases such as trout and salmon and some other native freshwater angling species. It may be difficult to convert this fussy feeder onto new food sources, in which case the Smelt could be used to scent new foods until they are readily accepted.

Here is a video of the snake after three vitamin B1 injections a week later, moving much more normally, more alert and responsive than before:

 

For further reading on this topic have a look at these links:

http://www.gartersnake.info/articles/2012/all-about-thiaminase.php

http://www.ces.ncsu.edu/gaston/Pests/reptiles/gsnakecare.pdf

 

Renal Tumour in a Chameleon: A Case Study.

A one year old male Panther Chameleon presented to the clinic following a one week history of progressive hind limb weakness, loss of motor function, swelling of the left knee and sleeping with his back legs dangling from his branch. He was still eating although his appetite was reduced. His owner was very knowledgeable and experienced in keeping reptiles, and his husbandry and captive care sounded excellent when taking a full clinical history and appraisal. There had been no changes to his routine or care, and no known history of trauma. His left knee joint however was visibly enlarged and swollen compared with the right hand side.

Hind limb paresis unilateral swollen stifle

On clinical examination, the joint was swollen but didn’t appear painful on palpation. However he was demonstrating bilateral hind limb paresis, or loss of motor function. Gripping was much reduced in the back feet compared to the front, and he appeared much weaker on the pelvic limbs also. Similarly he was reluctant to bear weight on the left hind compared with the right. Sensory function was intact and present in all limbs. This examination allowed me to form a reasonable diagnosis of a neurological problem, most likely a spinal lesion in the lumbar region or an intra-abdominal mass placing pressure therefore impinging on the nerves in this area resulting in compression and subsequent loss of motor function. I should mention here that I had seen a photo of this chameleon on a forum I am a member of the previous day when the owner asked for advice. From a photo alone it would have been impossible for me to pinpoint the problem or give a reasoned diagnosis as I could when the animal was in the clinic and I could perform a full neurological examination. For this reason I would always warn owners to beware accepting an online diagnosis based on a photo alone. If in doubt, a vet visit with a reputable reptile vet is really worthwhile.

Hind limb paresis perching

I explained to the owner that based on the issues I was seeing, I suspected an abdominal mass was the worst case but highly likely scenario, so we decided an X-ray was the next step. I took a dorso-ventral view after giving the chameleon some anaesthetic gas to allow me to tape both legs in position so I could get the best image possible to compare the knee joints in the same position. The X-ray however showed a very serious and obvious problem quite apart from the swollen joint. The entire abdomen of the lizard was full of air and the internal organs were all compressed. Air on an X-ray is black, and in normal chameleons the lung shadows demarcated by free gas extend a little over halfway down the length of the abdomen. Chameleons are fairly unique in that they also have finger like extensions or air sacs extending very far back towards the tail end of the body which are lined with a very thin transparent tissue almost like cling film. Therefore this is very prone to rupture from trauma, infection or damage during surgery for example.

DV view

I took a lateral view to confirm the organs were compressed ventrally (towards the bottom or belly of the abdomen), which highlighted that in fact a lung or both lungs were ruptured and air had leaked into the free space within the abdomen. I was also curious to gain another view of the very dense whitish-grey mass in the caudal or tail end of the abdomen just before the pelvis, which was occupying the entire width of this section of the abdomen. Unfortunately, on the lateral view this corresponded to the site of the kidneys and confirmed my worst fear that a kidney mass of some description was responsible for the nerve impingement and neurological signs on presentation. The kidney mass may have been an abscess or a congenital problem such as hydronephrosis present from birth which was gradually causing a growth in size over time. Similarly it may have been a tumour but it was difficult to tell from X-rays alone. The swelling of the joint in the left knee could have been explained by trauma associated with reduced motor function, the assumption being that he injured it in the preceding days whilst dragging it behind him.

Lateral view

The prognosis based on a renal or kidney mass of that size no matter what the underlying cause was unfortunately quite grim, not to mention the issue of air within the abdomen causing breathing problems and compression of other vital organs. After lengthy discussion with an upset owner, it was decided that it would be fairest and most humane to put the chameleon to sleep and prevent further suffering. Any treatment or further diagnostics would have had to be very invasive and highly unlikely to bring a resolution to the problem. In order to bring a resolution to the case and for the sake of education, the owner kindly allowed me to open the abdomen following euthanasia in a post mortem examination to confirm my diagnosis of a renal or kidney mass, and ascertain the nature of the lesion. Sadly my suspicion of a renal tumour was confirmed; quite a surprising diagnosis in such a young animal you might say. However renal lymphoma, which is one of the more common cancers in reptiles, is unfortunately not exclusive to older animals as in many other cancers. Several other cancers are also reported in reptiles. In this case, the classification of the tumour would not affect the outcome of the case so I did not send any tissue samples for pathological classification. A very sad case, but the positives if any can be taken from it were that I and hopefully other veterinarians can learn from this little chameleon’s death. I’m therefore very appreciative to the owner for allowing me to write this up and share the case study.


WARNING: THE FOLLOWING PICTURE IS GRAPHIC IN NATURE, SHOWING THE POST MORTEM FINDINGS. PLEASE DO NOT VIEW IF YOU ARE SQUEAMISH OR EASILY OFFENDED. I INCLUDE IT HERE FOR EDUCATIONAL PURPOSES ONLY SO THAT SIMILAR CASES MAY BE DIAGNOSED EARLIER IN FUTURE WITH THE EXPRESS PERMISSION OF THE OWNER OF THE ANIMAL IN QUESTION.

PM findings labelled