An Introduction to Amphibian Medicine

I recently gave a talk to veterinary students at the Royal Veterinary College Zoological Society in Camden, London which was also video linked to their Potter’s Bar/Hawkshead campus about amphibian medicine and why it is relevant, not only in private practice but also on a global scale in conservation and laboratory research. Below is the link to the presentation, which outlines some of the topics I discussed:

Any questions are welcome in the comments section. Feel free to share.

Frog Enucleation: Eye Removal Surgery

Eye surgery

Eye surgery

Splat the albino horned frog (sometimes called Pacman frogs because of their large mouth and appetite!) somehow injured his eye, presumably by jumping into one of the furnishings in his vivarium. Unfortunately, the eyeball itself was ruptured and could not be saved so it had to be removed, or enucleated. Here he is in an anaesthetic bath containing dissolved anaesthetic drugs that he is absorbing through his skin.

2 Once anaesthetised, I also injected some local anaesthetic around the eye socket and behind the eye itself. He had earlier been given pain relief and antibiotic injections to ensure he was comfortable and to prevent infection. I carefully dissected out the eye from the underlying ocular muscles lining the eye socket. 3

Once the eye had been removed, I placed collagen implant into the socket and packed it well to prevent bleeding and allow the remaining space to fill in with new tissue as it heals. At this point we started to rinse Splat in order to start the process of recovery from his anaesthetic.


Here he is after the surgery having closed the eyelids with dissolvable suture material. Now it was time to recover him and wake him from his operation.


We placed him in clean, de-chlorinated water and irrigated him regularly whilst keeping him warm in order to dilute the anaesthetic residue in his skin and keep him maximally hydrated so that he could recover and wake from anaesthesia. He recovered well, and went home the next day having been given another pain relief injection and oral antibiotic drops for the owner to administer. Here’s hoping he will be fighting fit in no time!

Salmonella: Transmission from Pet Reptiles

Zoonoses or Zoonotic diseases are those that can be transmitted between humans and animals. Salmonella is a zoonosis from pet reptiles that I am asked about on a fairly regular basis, and usually relates to the risk associated with reptile pets and Salmonellosis in humans. Whilst reptiles, amphibians and many other exotic pets can and do transmit Salmonella infection from time to time, sensible hygiene precautions can generally prevent this occurrence. Other precautions are recommended such as refraining from buying wild caught animals which are more likely to be infected, but also may be stressed and debilitated leading to enhanced shedding of infective material. Similarly, buying pet reptiles from clean, professional outlets or breeders may also reduce the risk of acquiring an infected animal in the first place due to decreased chances of transmission between animals where hygiene and cleanliness are scrupulous. Many different Salmonella species and serovars have been isolated from reptiles commonly kept as pets, several of which are infectious to humans.


The difficulty in assessing infection risk from reptile pets lies in the fact that certain Salmonella spp. can be commensal organisms in the gastrointestinal tract of pet reptiles, and also in that they are often intermittently shed so even if screening faecal samples it can be difficult to ensure a pet reptile is Salmonella free. Pets can appear perfectly healthy with no outward signs of infection yet carry a pathogenic strain that could result in severe illness in humans. Transmission to humans is usually via the faecal oral route, and as such any contact with faecal material should be minimised. Hygiene precautions such as washing hands after handling animals, wearing gloves for cleaning reptile housing and for maintenance of aquatic environments and filtration systems are the best defence against infection. Salmonella bacterial cells have been demonstrated to survive and remain infective in the environment for long periods of time, up to 6 months in dried reptile faeces and up to 6 weeks in contaminated aquarium water. Therefore, indirect transmission from the environment to oral ingestion can also be a significant route of infection in homes with reptile pets, particularly where cleanliness and hygiene practices are poor.


Signs of infection in humans include diarrhoea, vomiting, lethargy, abdominal cramps/pain, fever and in severe cases dehydration or even septicaemia and death. The most serious risk for infection is in young children, the elderly and immunocompromised individuals. One of the issues which comes up from time to time in the media, is whether reptiles and amphibians are suitable pets for children in the first place. This debate raged most notably in the 1980’s and early 1990’s when thousands of baby terrapins were being sold to young children in the UK and USA during the teenage mutant ninja turtles craze, resulting in several high profile cases of Salmonellosis in children. Several more recent high profile outbreaks in the USA have linked Salmonella outbreaks in children to aquatic frogs sold for home aquaria.

Transmission can be increased in young children for a variety of reasons, mainly due to not washing hands after handling pets or putting their hands in faecal contaminated water and then touching their mouths. Immunity in young children is also underdeveloped compared with healthy adults so transmission risk is again increased. As such, it is prudent to advise against aquatic pets such as turtles and frogs for young children for safety reasons as much as for the fact that these are specialist pets requiring detailed care and environmental conditions. In a household with very young children that would not understand these precautions, it may be better to limit access to such pets or consider waiting until children are a bit older to allow interaction with them. Similarly, it may be worth re-homing pet reptiles or amphibians if there is a member of the household who is on immunosuppressive medications like steroids or chemotherapy agents, or those with immunocompromising conditions. The alternatives would be rigorous and regular testing to screen for Salmonella spp, recognising that several tests are needs to rule out the disease and also that strict biosecurity will have to ensure infection is not introduced. This could potentially be very difficult to achieve especially considering some outbreaks of pathogenic Salmonella have been traced to rodent or insect food items required for many captive reptile diets.

If keeping reptiles or amphibians in the home with children it is crucial to teach them the importance of good hand washing after handling any animal, not just exotic species. Supervised handling if at all should be encouraged. Cleaning of reptile housing and equipment should never be carried out in areas where food is to be prepared, or drinking water is sourced or even in showers and baths used by the household. Preferably these tasks should be carried out outside the home or in a dedicated sink or washing facility. Cages or tanks housing exotic pets should be cleaned and disinfected with an appropriate disinfectant at the correct concentration on a regular basis. This is especially important for aquatic species who obviously occupy faecal contaminated water and therefore often have a higher potentially pathogenic load of gastrointestinal micro-organisms than other species.

In summary, perhaps reptile and amphibian pets are too great a risk for certain households depending on what practical arrangements can be made to limit risk of infection to vulnerable individuals, particularly young children. It is important to be aware however that with sensible hygiene precautions such pets pose a very low risk and incidence of disease transmission from pets to owners is greatly exaggerated by the media when occasional cases occur. Any signs of gastrointestinal illness in households containing such pets should be investigated by a medical doctor, especially in the vulnerable groups discussed. It is important to also mention that gastroenteritis caused by Campylobacter spp is also sometimes transmitted by captive reptiles and amphibians, and can cause similar signs.


Click to access Salmonella-Information-for-Veterinarians.pdf

Click to access Zoonoses-fish-reptiles-amphibians.pdf

Click to access reptile_associated_salmonellosis.pdf

Click to access art19581.pdf

Click to access 11285792.pdf

Back to Basics: Keeping pet reptiles & amphibians

Keeping exotic pets such as reptiles and amphibians has massively gained in popularity in recent years. When I was a youngster, I was always interested in nature and wildlife and a lot of what I learned came from observing creatures in their natural habitat, on TV and in real life. Ask my bemused mother. She tells me aged 4 I was more interested in turning over massive rocks in the garden looking for creepy crawlies than watching cartoons! I guess I was doomed to be a nature geek from the start.

In any case, after collecting bugs, tadpoles and mini beasts and keeping them in jam jars as a small child, I graduated and got my first ‘exotic pets’ when I was about 12 years old for Christmas. This was of course after much pleading and convincing my very patient parents it was a good idea and I knew what was involved. The reptile scene in Ireland back then was pretty small, so I managed to find a pet shop on the other side of Dublin that would import some American Green Tree Frogs (Hyla cinerea) from the UK for me. I awaited their arrival eagerly but was awaiting disappointment. Four fairly stressed and none too healthy tree frogs were collected from the pet shop and duly set up in the planted vivarium I had painstakingly prepared for them in the weeks before. I had read every scrap of information I could find in my collection of books. The internet age of information at your fingertips was yet to come!


A Grey & Green tree frog I later kept having learned my lessons first time around

New pics 002

Naturalistic vivarium in which I housed several tree frogs and Anole lizards, a practice not recommended for beginners as need experience creating the right subtle conditions for all to thrive

Sadly three of the four frogs has abrasions and ulcerations on their skin, and two out of the four very quickly succumbed to secondary infections and died soon after. The other affected frog I managed to save by going to my local vet (a rather rough around the edges, Irish country vet type) and asking him for various antiseptic old fashioned remedy chemicals I had read about in one of my amphibian books. These were potions that wouldn’t have looked out of place on the shelves of an ancient chemistry lab. Malachite Green, Potassium Permanganate and Mercurochrome Blue if my memory serves me correctly. The vet seemed quite bemused by this tiny budding frog doctor at his door and handed over the colourful crystals charging me the princely sum of 50 pence.


That pair of tree frogs survived for many years, after I had got them through the initial acclimatisation period and provided me with hours of fascination observing their behaviour. In the summer any daring bluebottle or housefly that entered the kitchen would be captured by myself, my Dad or brothers and released into the tree frog tank. We had great fun watching them stalk their prey through the branches and vegetation of their enclosure. In the winter I would reduce their temperatures and day length gradually and settle them down to a few months of hibernation before rousing them again in Spring by gradually raising their temperatures and lighting or photoperiod. It was great to see them leaping about again and eagerly searching for food each year. On hot summer evenings (few and far between in Ireland, let me tell you!) the male would call for hours on end, a loud, duck -like quacking sound. My mothers rule was that none of my ‘pets’ were allowed in the house so luckily this racket wasn’t too disruptive. My father, fearing the garage would burn to the ground due to the amount of extension leads I was using, erected shelves and roped in an electrician friend to install electrical sockets in the garage for my ever expanding collection of tanks and aquaria housing various frogs, toads, turtles, snakes and lizards. If I wasn’t busy in the garage tending to and observing the reptiles and amphibians that enthralled me so much, I was often reading about their natural history. Lesson number one: if you’re going to keep an animal successfully, read as much as you can about them!

What ever happened to reading a book?

What ever happened to reading a book?

Which brings me to the point of this article. The most useful and simple advice I can give to any keeper of reptiles and amphibians is to learn about their natural history in the wild, and replicate these conditions in captivity. These are effectively wild animals, and need to be treated as such. The early days of the reptile community when I was growing up revolved mainly around a small shop in Mother Redcaps Market in the old historic part of Dublin near Christchurch Cathedral. The shop was run by two insanely knowledgeable and passionate herpetologists who I know and respect massively to this day. There was a real community of people who would meet and discuss ideas in this tiny shop, and the Herpetological Society of Ireland ( was borne out of these informal meetings. The difference I see between the keepers and enthusiasts back then compared with today is that most took a huge interest in the natural behaviours and habitats of their species of interest. Most could reel off the Latin names (and know the significance of them), their natural geographical range, what type of climate the species was accustomed to, the unique feeding habits, natural diet, seasonal variations, subspecies differences, breeding habits, micro-climates, ecological niche and so on. The hobby was not about keeping a ‘pet’ reptile, it seemed to be more about scientific study of a species for many keepers. There was of course many who kept a single corn snake or lizard and doted on it as a beloved pet, but for the most part keepers enjoyed observing the unique biology of this group of animals.

Evolution, Diversity & Natural History

Evolution, Diversity & Natural History

Over the years, as the reptile hobby has gained popularity, these pets are becoming more ‘mainstream’ and are sometimes a better option for people who cannot devote the space, time and economical requirements needed caring for a more traditional pet such as a cat or dog. Unfortunately, with this trend a lot of people have seen pet reptiles and amphibians as lower value pets, and not treated them as worthy of great care and attention. This article by a very knowledgeable colleague makes for an interesting read in that respect, over at Reptile Apartment ( On the other hand we have a whole new wave of extremely devoted pet owners who would do anything for their beloved reptile but perhaps are missing some of the knowledge and understanding of their natural history which can lead to stress and health problems.

The basis of keeping such pets successfully is in researching their requirements and providing as near a replication of wild conditions as possible. All too often in my work time I am presented with a sick animal and a bewildered owner wondering why their animal is unwell. Frequently the owner when questioned knows very little of the conditions required to keep that animal healthy. They may know what species it is and what it eats, but not where it hails from in the world, what temperature it needs to be kept at or even what temperature it is being kept at in their own vivarium! Temperature, humidity and lighting requirements are the fundamental basics of providing reptiles and amphibians with the correct captive environment to thrive, are very specific and vary from species to species. But the number of people who do not know this basic information about how they are keeping their pets is staggering. I will often ask about what equipment the owner is using in a reptile consult for heating and lighting for example. A common answer is: “Oh the correct ones the pet shop sold me”. OK, so my next question will be what temperature their vivarium reaches in the warm end and the cool end, and what it drops to overnight? Sadly I am often met with a blank stare. All too often an owner buys a reptile from a pet shop, listens for a half hour to the shop assistant as to what the animal requires, and never does any further research or reading on what is involved in it’s care. If they are lucky they will have gained some good advice from an experienced and knowledgeable reptile enthusiast. Commonly, they will have taken the advice of a young person who is keen but has received minimal training and is far from knowledgeable on reptile care. A 20-30 minute conversation going over temperatures, heating equipment, cage design, food items, supplements, lighting and so on is a lot of technical information for a new owner to take on board. It is simply not enough to absorb and retain the level of knowledge required to successfully keep a pet reptile amphibian happy and healthy for a natural lifespan. The number of pets that die in captivity soon after being acquired is astounding, and a very poor reflection on the exotic pet hobby in general. In fact, it is one of the tools and statistics used factually or misleadingly depending on your viewpoint to discredit and campaign against the hobby by many animal rights activists (

The point I’m most trying to make is that if you are willing to devote a great deal of time researching a species natural history, this will give you a far better chance of successfully keeping that animal as a pet. Buy a book, read care sheets online, join in conversations on forums with other keepers of the same species BEFORE buying the animal in question. If everyone took this effort there would be far better welfare for captive reptiles and amphibians. There is an abundance of information out there, and it can be overwhelming to decipher what is correct and what is wrong. However, if you apply first principles of the natural history of your species in question you can come up with a list of appropriate habitat type, temperature and humidity range, seasonal variations in environmental parameters, social behaviour considerations and so on. Then you tailor the facilities and equipment available to you to replicate such conditions in captivity. The approach I see all too frequently of giving a prescription of equipment needed for a particular species is totally unsuitable in many cases. For example, many care sheets will recommend a certain wattage heat lamp for a certain size vivarium, which doesn’t take into account the ambient temperature in the pet owners home, how cold the room is in winter versus summer and so forth. They may also state what brand of UVB tube to buy, but leave out factors like the longevity of that bulb, how often it needs to be replaced or the fact that you need a stronger UVB output bulb if it is outside the vivarium shining through mesh as opposed to hanging inside the vivarium itself. Better advice would be to choose the appropriate wattage of bulb that provides the correct temperature gradient in your particular setup, encouraging the use of a simple and inexpensive thermometer to measure said temperature! Experimenting with the equipment for your particular circumstances to produce the right environment is critical. Similarly, you will often find prescriptive advice about your particular animal along the lines of: ” This species doesn’t need a heat lamp, it should be kept with a heat mat alone. I have done it that way for years”. The first problem that arises when advice like this is followed blindly is that it relates only to how that particular person keeps their animals. Maybe that person has a large collection of leopard geckos in a room devoted to reptiles and keeps them in a rack system containing many animals closely together. Maybe for their reptile room the ambient temperature is enough as background heat to keep their animal healthy and well. Apply the same advice to a young boy keeping his first leopard gecko on his bedroom dresser in a glass tank and your advice becomes inappropriate or dangerous. The boy is just using a heat mat under half of the glass and creates a wholly inappropriate environment where the ambient temperature of the tank itself is room temperature in the cool end, subject to daily and seasonal variations in the temperature of the bedroom, and the gecko has the choice of either sitting on substrate warmed by the heat mat or being elsewhere in the tank at a lower temperature than required. Add to the situation that the boy has been told geckos need a hide box in their vivarium and the boy places it in the cooler end of the tank. The gecko is a juvenile so is stressed and will not eat because it is either hiding but too cold to have an appetite or digest it’s food, or it is warming up out in the open and feels threatened by the possibility of predation. All of these subtle factors can lead to a debilitated, stressed animal which succumbs to illness and dies. The boy did what he was told by the pet shop, or read on a care sheet online, but the gecko still died. The fact is he took far too simplistic an approach to keeping what are highly specialised pets that don’t forgive shortcuts in care. To purchase the correct set up and equipment needed to provide the correct environment and care for his gecko may have far exceeded what his parents were willing to spend on his birthday present. So the pet shop or care sheet gave them prescriptive advice and shortcuts ignoring the subtleties of environmental control and they assumed they were doing right.

Those tree frogs I bought as a 12 year old succumbed to transportation stress and being kept poorly in the pet shop both in Dublin in dry conditions under a high wattage heat lamp and perhaps also in the UK before they found themselves in my care. I managed to save two of the four which went on and thrived afterwards, mainly because I read and understood in great detail what their natural requirements were and used what equipment and conditions I could afford at the time to replicate these exactly. The advice I give to anybody new to keeping reptiles is to treat their reptiles and amphibians not so much as humanised pets but as wild animals, and see yourself as a zoo keeper aiming to replicate wild conditions. Stress is a big killer as it weakens their immune system and natural defenses. Handling or disturbing your animals too frequently should be avoided, especially in newly acquired animals or shy species. Fluctuations in temperature or incorrect temperatures even by a few degrees are enough to depress immunity or digestion over time for example. Keeping a high humidity species in drier conditions than those in the wild will lead to serious health issues. Feeding a diet far higher in fat or deficient in certain minerals and vitamins is a massive cause of mortality over time in our exotic pets. When researching your pet before you decide if you can care for it, ignore the ‘experts’ online shouting prescriptive lists of how to keep the species in question, unless they are shouting lists of scientific tangible information on the specific conditions needed and offering advice on how best to replicate those conditions. There are a multitude of accessories and equipment available nowadays, the important thing is to know not only how to use them but why you are using them and monitoring if they are helping you provide the perfect replication of the natural environment needed for your pet.

If you are interested in hearing me speak a little more on the importance of reptile housing and care then I am giving an online lecture next Monday June 23rd at 8 pm, registration and attendance is FREE and I will be giving some more throughout the summer so stay tuned:

Would love to hear your comments, so feel free to send them in below.

All the best,




Lungworm in dogs, but what about in reptiles?

Throughout the UK we are seeing a rise in the number of lungworm cases in dogs, which is a life threatening condition if left untreated, and is carried by slugs, snails and foxes. More information here:

However, I’ve recently been asked about the risks of lungworm for pet reptiles on an exotic forum I contribute to. Some reptile keepers were discussing feeding snails to their lizards and wondered if this parasite could be passed on considering slugs and snails in the UK are the intermediate host for canine lungworm (Angiostrongylus vasorum). I have to admit my answer was I didn’t know for certain what the risk was if any, but I did know that amphibians such as frogs could act as an intermediate host when preying on infected slugs and snails. I also knew of certain other parasites of the lungs and circulatory system that specifically infect reptiles so thought I would write a short blog post to clear up any concerns.

The canine lungworm (A. vasorum) requires that the eggs shed in faeces of the primary mammalian host (dog or fox) are ingested in the environment by an intermediate mollusc host such as a slug or snail. The parasite then undergoes a further stage of development in the snail host before shedding infective cysts into the environment in the hope that these are ingested again by a canine such as a dog or fox. However, there is evidence that UK common frogs act as a host for the parasite also, either as an intermediate host like the snail or as a paratenic host depending which infective stage it becomes infected by (

Lungworm cycle with frogThe term paratenic describes a host which is not essential for the development of the parasite, but can maintain the parasite and shed infective stages until the next part of the life cycle can resume. So in this example the snail and canine host can continue the cycle from ingestion of infective stages in frog faeces. Similarly, frogs can infect dogs directly if they are ingested. In most paratenic hosts there are no discernible ill effects of infection, as they merely act as a vector of infective stages to the required hosts by environmental transmission. However, it is well recognised in the field of parasitology that intermediate and paratenic hosts can undergo subtle changes in behaviour and physiology engineered by the parasite itself, that ultimately lead to an increased likelihood of ingestion by the definitive or primary host. So for example, it has been shown that mice (intermediate host) infected with certain nematodes show increased diurnal activity and diminished predator avoidance behaviours leading to increased death by predation in infected individuals, thus aiding transmission to the mammalian or avian predator (definitive host). For these reasons, if we can avoid infecting our captive reptile pets with potentially harmful parasites we should make a substantial effort to do so. As an aside, this was the topic for my undergraduate dissertation, so parasitology and parasite behaviour is a fascinating area for me. Here’s some amazing evolutionary adaptations of parasites and their hosts if you are interested:

Anyway, back to canine lungworm and feeding snails to pet reptiles, or amphibians for that matter. There have not been many studies into the effects of this parasite on reptiles mainly because there are no apparent economic reasons to undertake such studies, although it has been recognised that they can act as paratenic hosts. Because the common frog has been proven to act as both paratenic and intermediate host, presumably with the subsequent changes associated with infection above, I would warn against feeding native wild caught slugs and snails to captive reptiles and amphibians as a result. If the frog can act as both intermediate and paratenic host then it is likely that native reptiles can, and by default I would suggest that non-native amphibians and reptiles could also be at risk. The likelihood is that even if captive reptiles do not have any ill effects, over time the parasite burden may become heavy resulting in debilitation or complicating other health issues, and could even act as a reservoir of infection for dogs in the household. Equally, as the effects of infection are not known it is better to be safe than sorry, and so finding alternatives to using wild snails and slugs is probably the safest option. One method would be culturing your own mollusc supply, using either Giant African Land Snails which are readily available and easy to culture, or obtaining a supply of edible snails from the restaurant supply trade and culturing these at home as a food source for your reptile pets, many of which specialise or at least are adapted to consuming such prey in the wild. Caiman Lizards, skinks, certain Chameleons, salamanders and frogs all relish snails and slugs in their diet. If you are considering feeding such items a captive bred clean supply is probably the best source. It is also important to beware feeding wild snails and slugs due to the risk of slug bait poisons and insecticide or herbicide residues, even if you don’t use them in your own garden. You would be surprised how far a hungry slug can travel, and can’t always be sure your neighbours are as environmentally-minded or pet-conscious with their use of chemicals.
Apart from the possible risk of infection with canine lungworm, reptiles and amhibians can become infected with specialised lungworm parasites of their own leading to ill health and even death in some cases. It is important to be aware of the risk of parasites in general in captive reptiles, and routine parasite screens should be carried out on any new additions to a collection as well as annual or biannual screening tests in large collections. Protozoan infections, roundworms, tapeworms and pinworms are the most common offenders, but lungworm infections are also being diagnosed more and more frequently in the reptile trade. Reptile lungworms include Rhabdias spp. in snakes and Entamelas spp. in lizards. They are spread by direct transmission, differing from the canine lungworm in that they have no intermediate host. Eggs shed in faeces are directly infectious to the host reptile and other uninfected individuals that come in contact with this environmental contamination. Infection occurs through ingestion of faecal contaminated material or direct penetration by the larvae through the skin of the host. This mode of transmission means it is extremely easy to unwittingly spread the parasite widely through a large reptile collection. The most common findings in infected individuals are respiratory signs such as gaping, wheezing, foamy secretions from the airway and respiratory distress resulting from pneumonia. It is important to consider this parasite as a potential factor in respiratory infections that are longstanding or do not respond to standard effective treatments. As with most parasites, the eggs of the parasite are easily found on routine faecal examination or sometimes by examining saliva and respiratory secretions under the microscope. Reptiles that show these symptoms should always be isolated from healthy animals. Quarantining wild-caught or new additions to a collection is always recommended. If any of the above symptoms are noticed or if your reptile is generally unwell and fails to thrive a faecal parasite screen and examination by a competent, experienced vet is recommended.

I hope this topic was of interest and if you have any other suggestions for blog topics please leave them in the comments or on our Facebook or Twitter pages at Sean McCormack Mvb and @ExoticPetVet.

All the best,