Veterinary Conference Papers

[El Lobo]

I have a reasonable collection of veterinary papers presented at conferences and have been going through them to find topics applicable to reptiles. None of them are specifically oriented towards BTS but the information can still be useful.

I would like to keep this first post as an index so that if anyone else has other papers they would like to add, this post can be edited by moderators as an ongoing index.

Feedback would be appreciated to know if this is what members want.

INDEX

1. Veterinary Abbreviations

2. Selected Endoparasites in Reptiles

3. Diagnosis and Treatment of Sick and Injured Reptiles and Mammals

[El Lobo]

Veterinary Abbreviations

These mostly appear in papers relating to dosage of medications.

IM. intramuscular injection
IV. intravenous injection
SC. subcutaneous injection
IP. within the abdominal cavity
PO. per os = orally
IN. intranasal
h. hour
q. every
sid. once a day
bid. twice a day
tid. three times a day
qid. four times a day
qod. every other day
o.d. right eye
o.s. left eye
o.u. both eyes
a.d. right ear
a.s. left ear
a.u. both ears
a.c. before meals
p.c. after meals

[El Lobo]

Selected Endoparasites in Reptiles

Jean-Michel Hatt, Prof.Dr.med.vet., DACZM, DECZM (Avian)
University of Zurich, Zurich, Switzerland
20133813

Introduction

Endoparasitism is a major cause of disease in captive reptiles. In captive bred animals, the clinician will face a fairly limited number of parasites. However, it must always be kept in mind, that a significant number of wild-caught reptiles are still offered for sale, and these animals may harbour parasites which would not typically be expected (e.g., pentastomids, cestodes).
Two recent studies have retrospectively evaluated reptile diseases presented to specialised exotic animal practices. Langenecker (2006) reported the clinical findings in 2620 reptiles presented to the Clinic for Zoo Animals, Exotic Pets and Wildlife of the Vetsuisse Faculty University of Zurich.1 Sinn (2004) analysed 1941 reptiles submitted for post mortem examination to the Ludwig-Maximilian-Universität in Munich.2 Both studies found that tortoises (Testudo spp.) were frequently affected by endoparasites (25% and 31%), whereas in terrapins (Trachemys spp.) endoparasites were rare. In snakes, protozoan (amoebiasis and cryptosporidiosis) are of major concern, and it appears that the species Boa constrictor is more frequently affected by endoparasites than the ball python (Python regius). 40% of lizards had endoparasites, with oxyurids and coccidia in bearded dragons (Pogona vitticeps) being the main endoparasites diagnosed.
Endoparasites in reptiles should be seen as important predisposing factors for the development of diseases and clinicians are advised to include a parasitological examination in any reptile patient. The present summary emphasizes the main endoparasites in captive reptiles. For further information the reader is referred to the textbook by Schneller and Pantchev.3

Tortoises

Several institutions have reported endoparasitism in tortoises. In the wild, tortoises typically have a balanced parasite burden. Under captive conditions, however, an imbalance is more likely to occur because of stress factors such as inadequate diet, low temperature, or overcrowding. An imbalance of endoparasites may represent a serious threat to tortoises and may predispose them to other diseases. Some parasites are important parts of the intestinal microflora, especially ciliates, such as e.g., Balantidium and Nyctotherus. Treatment is not warranted. The most frequently diagnosed nematode in tortoises is of the order Oxyuridae. The clinical significance is unknown, but in animals showing signs of disease such as anorexia, weight loss or diarrhoea, treatment is recommended. Fenbendazole (50 mg/kg po SID for 5 days) and pyrantel (5 mg/kg po with a repeated treatment after two 2 weeks) have been used to treat nematodes in tortoises. Regarding the use of fenbendazole, it should be noted that in one study in Hermann's tortoises (Testudo hermanni) adverse effects were noted.4 The animals were treated twice with fenbendazole 50 mg/kg for 5 days with a 2 weeks break. Blood analysis revealed extended heteropenia with transient hypoglycemia, hyperuricemia, and hyperphosphatemia. An alternative might be the intracloacal application of fenbendazole, toxic effects have not been observed. Recently, another nematode treatment was proposed for tortoises, lizards and snakes.5 A mixture of 1.98% emodepside and 7.94% praziquantel (Profender®, Bayer AG, Leverkusen, Germany) was applied onto the skin of different reptiles. Reptiles up to 5 g body weight received 1-6 µl, those of up to 50 g body weight 7-70 µl, those of up to 500 g body weight 70-700 µl, and those up to 5 kg body weight received 700-7000 µl.
An important pathogenic protozoan parasite in tortoises and occasionally in terrapins are flagellates, Hexamita, that affect the kidneys. Infection occurs after ingestion of cysts, that are shed in the urine. Initially the parasite colonizes the intestine and subsequently invades the renal organs via the cloaca. The excreta of affected tortoises are soft and the urine has a jelly-like appearance. The motile parasite is easily identified in fresh samples. Clinical signs are linked to nephropathy and secondary effects may include metabolic bone disease. Treatment is with metronidazole (50 mg/kg po SID during 10 days) and disinfection of the terrarium is paramount to avoid reinfestation.

Lizards

Endoparasites are frequently diagnosed in agamid lizards (e.g., bearded dragon), chameleons and geckoes, but rarely in Iguana spp.. In one study it was found that in affected bearded dragons (n = 63), 47% had Oxyurids, 39% had coccidia, 4% had flagellates, and 3% had Amoebae.1
Whereas in tortoises and snakes coccidia do not appear to be often related to disease, these parasites, especially Isospora and Choleoeimeria, can be pathogenic in lizards. Isospora amphiboluri can cause significant morbidity and mortality in juvenile bearded dragons, while adults may be shedding large numbers of this parasite without clinical signs.6 Besides bearded dragons, chameleons are frequently affected too.
Pathogenicity of coccidia is linked to enteritis, which results in malabsorption and weight loss as well as dehydration. The latter leads to nephropathy, which ultimately will lead to death. Diagnosis is made by faecal flotation and detection of oocysts. Treatment is attempted with toltrazuril (10 mg/kg po twice). Small lizards may be difficult to treat by applying the medication individually. The author has successfully treated small panther chameleons (Chamaeleo pardalis) by spraying the animal for 5 days with a 0.1% solution of toltrazuril. Anticoccidial treatment is unsuccessful against Choleoeimeria, which affects the mucus membrane of the gallbladder and results in obstruction.

Snakes

In captive snakes, the most important parasites are protozoans, Amoeba and Cryptosporidia. Both parasites are transmitted directly by the faecal-oral route.
Entamoeba invadens is the species most commonly linked to diseases. Clinical signs range from depression, anorexia, CNS signs and blood diarrhoea (due to colitis) to sudden death. Clinical signs typically occur late in the disease process. Amoebae can result in significant mortalities. Besides snakes lizards and carnivorous tortoises may also succumb to disease. Herbivorous tortoises are considered to harbour this parasite without showing clinical signs. It is therefore generally recommended that herbivorous tortoises should not be housed together with carnivorous reptiles, especially snakes. Amoebae cysts or trophozoites can be detected in the faeces. Adding a drop of iodine to the fresh faecal sample facilitates the detection of the Amoebae. For external analysis, samples should be fixed and shipped using sodium acetate-acetic acid-formalin (SAF) fixative. Animals suffering from amoebiasis should be separated from cagemates for treatment and the terrarium thoroughly disinfected. Desiccation helps to eradicate Amoebae. Treatment may be successful with a combination of metronidazole (50 mg/kg po SID during 10 days), which only affects trophozoites and paromomycin (50-100 mg/kg po SID for up to 4 weeks), which also affects cysts. It should be noted that paromomycin is potentially nephrotoxic and monitoring the hydration status of the patient during treatment is important. Prognosis is guarded to bad.
Cryptosporidia represent an important threat to reptiles, especially snakes, because currently no effective treatment exists. Therefore, the detection of this parasite should be included in any reptile quarantine. The two main species of Cryptosporidia in reptiles are C. serpentis and C. saurophila. Both affect snakes and lizards. C. serpentis typically affects the stomach and results in hypertrophic gastritis, which is clinically obvious as a midbody swelling. Regurgitation has been observed in snakes with cryptosporidiosis. C. saurophila affects the intestine and clinical signs include weight loss and abdominal swelling. Juvenile geckoes appear to be frequently affected. If Cryptosporidium spp. are to be found, a fresh faecal sample must be submitted. The parasite is detected by special staining, PCR or ELISA. Treatment has been attempted with paromomycin, but this does not appear to completely eliminate Cryptosporidiaand euthanasia may be necessary to eliminate the risk of spreading.

References
1.  Langenecker 2006; Retrospektive Untersuchung zur Entwicklung der Artenverteilung und den häufigen Krankheitsbildern bei exotischen Heimtieren im Zeitraum von 1994-2003. Vetsuisse-Fakultät Universität Zürich, Zurich.
2.  Sinn 2004; Pathologie der Reptilien eine retrospektive Studie. Ludwig- Maximilian- Universität, München.
3.  Schneller , Pantchev. 2008. Parasitologie bei Schlangen, Echsen und Schildkröten. Edition Chimaira, Frankfurt a.M. 1.
4.  Neiffer, et al. J. Zoo Wildl. Med. 2005; 36: 661.
5.  Mehlhorn, et al. Parasit. Res. 2005; 97: S64.
6.  Greiner, Mader. Parasitology, 2006; 343.

[El Lobo]

Diagnosis and Treatment of Sick and Injured Reptiles and Mammals

Robert Johnson, BVSc, MACVSc, CertZooMed, BA
South Penrith Veterinary Clinic
NSW, Australia

Introduction

In Australia sick and injured native reptiles and mammals are common patients at veterinary clinics. Experienced wildlife veterinarians are often contacted by colleagues to provide advice in the treatment of these animals. This paper is not meant to be comprehensive. It will however outline some common presenting conditions, explaining a logical approach to diagnosis and treatment. Helpful tips relating to therapies and handling techniques for native fauna are included.

The Joey with Diarrhoea

Common causes of diarrhoea in orphaned joeys are candidiasis, salmonellosis, colibacillosis and coccidiosis. A full physical examination should always be undertaken. Joeys are often dehydrated and listless and will frequently lick their forelimbs when distressed. Signs of gut pain include grinding of the teeth and bloating. Faecal analysis will rule out coccidiosis, an often fatal disease in eastern grey kangaroo joeys in the transitional stage (weaning off milk and progressing to solids) and candidiasis. Joeys with candidiasis have a sickly sweet smell to their faeces and oral lesions (plaque and ulcers). There is often a history of antibiotic therapy, leading to an overwhelming yeast infection. Diagnosis is made by microscopic examination and culture of lesions and faeces for the presence of yeasts. Nystatin is the recommended treatment. Antibiotics should be used judiciously and adequate attention paid to hygiene. Oral or parenteral fluid therapy may be required. Faecal cultures should be performed in order to diagnosesalmonellosis and other bacterial infections. Carers should be warned of the zoonotic potential of salmonellosis.

The Greasy Possum

Exudative dermatitis is a chronic ulcerative or proliferative dermatitis affecting the common brushtail (Trichosurus vulpecula).1 Lesions typically include alopecia, exudation, crusting and in severe cases ulceration. An offensive odour is often present and the fur is matted and easily pulled out. The cause of the condition is likely to be multifactorial involving a variety of ectoparasitic, bacterial and fungal agents, trauma and stress.1 Mixed bacteria such as Staphylococci, Streptococci and Corynebacteria are commonly present, but are likely to represent secondary infection.1 Exudative dermatitis is frequently seen in dispersing subadult males, particularly in densely populated areas.

When treating these cases consideration must be given to the fate of the animal after rehabilitation. The release of a possum, especially a young male, back into a highly populated area, is not recommended. Severely affected animals should be euthanized. Topical and parenteral treatment (amoxycillin) is usually required. Spray preparations of chlorhexidine 0.05% can be used. Possums frequently resent applications of medications, especially on raw or ulcerated lesions and frequently require sedation or anaesthesia. In severe cases, anaesthetised animals may need to be clipped and bathed using antiseptic shampoo. Ointments containing silver sulphadiazine and chlorhexidine digluconate (Silvazine®, Smith and Nephew) or other commonly available small animal topical antibiotic, antifungal and corticosteroid preparations may be applied.

The Burnt Possum

Burns are common in free-ranging common brushtails and common ringtails either as a result of bushfires or direct contact with hot surfaces such as stove tops and fireplaces. Adequate pain relief (butorphanol tartrate [Butomidor Injection®, Ausrichter, 10mg/ml] 0.1-0.4mg/kg IM) and antiinflammatory treatment (meloxicam (Metacam®, Boehringer Ingelheim, 1.5mg/ml) 0.2mg/kg SC or tolfenamic acid (Tolfedine®, Ausrichter, 40mg/ml) 4mg/kg SC) should be given as soon as possible. Most animals will require anaesthesia for proper assessment of the degree of tissue damage. A decision whether to treat or not to treat should also be made as soon as possible. Treatment of wounds is similar to that for exudative dermatitis.

The Red Bellied Black Snake Caught in Netting

The red bellied black snake, Pseudechis porphyriacus, eats frogs and reptiles. During summer snakes frequently become entangled in bird netting used to protect outdoor ponds and plants. Often the netting becomes deeply embedded in the skin of the reptile. Most entanglements can be dealt with while the snake is manually restrained. If the wounds are on the caudal body restraint is managed by the use of a clear plastic tube. Snakes are coaxed head first into the tube and once a good portion of the snake has entered the snake is restrained by holding snake and tube in the one hand. If the injuries are more cranial restraint can be more difficult, often involving "heading" the reptile by an experienced handler.

Small tears and lacerations can be glued rather than sutured. Alfaxalone anaesthesia can be administered to "tubed" snakes via the ventral tail vein to facilitate examination and treatment in a safe manner.

The Dog Bite Blue Tongue

The common eastern blue tongue, Tiliqua scincoides scincoides, is a common prey for the family dog. Just with any dog attack victim a small puncture wound may not be an accurate indicator of the extent of the injuries suffered by the animal. Routine pain relief (tolfenamic acid 4mg/kg IM) and antibiosis (enrofloxacin [Baytril®50 Antibacterial Injection, Bayer, 50mg/ml] 10mg/kg SC q48 hrs) should be administered; the latter for at least 8 days. Radiography often reveals punctured or collapsed lungs and intracoelomic haemorrhage. An exploratory celiotomy will occasionally be required in order to assess accurately the nature of the injuries. Alfaxalone at a relatively high dose rate of 10mg/kg IV, by the ventral tail vein is recommended. Lizards are intubated and maintained on isoflurane and oxygen. Intubation can be difficult as the glottis is quite caudal and the tongue slippery and difficult to retract. A spatula is best used to identify the glottis. Intermittent positive pressure ventilation is given at 4-6 per minute, reducing to 2 per minute once a surgical stage of anaesthesia is reached.

The Squashed Turtle2,3

In eastern Australia the common eastern long-necked turtle, Chelodina longicollis, is a common victim of the motor vehicle. Turtles are presented to veterinary clinics in various states of shell trauma. It is important to identify the extent of trauma to underlying soft tissue. Fractures of the bridge have a poor prognosis as there is often damage to the underlying viscera. Male turtles may be presented throughout the year for treatment, however females are usually more likely to wander when seeking nesting sites in late spring and early summer. Veterinarians should become skilled in gender determination and radiograph all injured females. Injured egg bearing turtles may require induction of egg-laying. Oxytocin is used (10-20 U/kg SC or intracoelomically [ICo]) in conjunction with warm water soaks. Turtles usually lay 30-60 minutes post injection. Fractured shells are repaired using a variety of techniques, including wiring and ultraviolet light cured dental composite. Often injured turtles need to be "overwintered" so wildlife carers must be well-versed in the specific nursing and husbandry needs of rehabilitating turtles. A combination of "dry docking", partial or total immersion may be required, depending upon the site of the injury. Freshwater turtles will only eat in water, so methods must be devised to accommodate this habit and still keep wounds dry and clean.

The Flying Fox With a Torn Flight Membrane

Membrane tears are best not sutured and will eventually contract and seal naturally. Bats with large tears should be euthanized as extensive contraction of tissue will prevent the animal from flying. Tears should be treated as open wounds, applying chlorhexidine and saline topically. Care should be taken when handling bats, ensuring that all handlers, veterinarians and nurses are vaccinated against rabies. Emerging zoonotic diseases including Australian Bat Lyssavirus (ABL) and Hendra virus affect the megachiroptera (fruit bats) and microchiroptera (small insectivorous bats).

Venipuncture

Turtles

Long necked (Chelodina longicollis)--jugular

Short necked (Emydura spp.)--dorsal tail vein, metatarsal vein (larger turtles)

Lizards (skinks, dragons and monitors) and snakes--ventral tail vein

Possums, joey kangaroos and wallabies--lateral tail vein

Restraint

Firstly ask the question whether the animal needs to be handled. Often medications can be given in food and short examinations carried out without the need to handle the animal. Transferring animals from cage to cage or container to container may also be done without direct contact, thereby reducing the stress to the animal. If an animal, particularly a mammal, needs to be examined closely it is best done under general anaesthesia.

Anaesthesia

Reptiles

Reptiles should always be anesthetised at their preferred body temperatures (PBT), for example:

Freshwater turtles (26C)

Blue tongues (33C)

Diamond pythons (29-30C)

Bearded dragons (33C)

Alfaxalone is a safe and effective intravenous anaesthetic in reptiles. Recovery is smooth, with lizards and snakes taking approximately one hour to resume consciousness while turtles are slower taking 2-3 hours to recover. For lengthy procedures reptiles are intubated and maintained on isoflurane and oxygen administered by intermittent positive pressure ventilation (IPPV), 2 cycles per minute, 2-3%. Pythons may be intubated while conscious and induced with IPPV at 6 cycles per minute at 4-5%, until a surgical plane of anaesthesia is achieved and then reduced to 2 cycles per minute at 2-3%.

Echidnas

Gaseous anaesthesia using isoflurane and oxygen is the preferred method for echidnas. Anaesthetic masks for echidnas are fashioned from 10 ml syringe cases. Patience and great care are needed to apply the mask around the tender beak. The front legs of an echidna are very strong and will repeatedly attempt to pull off the mask. Echidnas are best handled for anaesthesia draped over the forearm of the assistant with the beak and front legs facing the anaesthetist.

Possums and Macropods (Kangaroos and Wallabies)

Alfaxalone at a dose rate of 2mg/kg IV or tiletamine/zolazepam (Zoletil®, Virbac) 2mg/kg IV or 4-5 mg/kg IM (Larry Vogelnest, veterinarian, pers comm) are commonly used for anaesthetic induction or short anaesthesia. Intubation can be difficult in macropods due to their long, narrow oral cavity and pharynx. Maintenance of anaesthesia using a mask is usually quite adequate. Large possums can be intubated without difficulty. Mask induction of possums and macropods using isoflurane and oxygen can be carried out while the animal remains within a Hessian bag.

Flying Foxes

Flying foxes should be fasted prior to anaesthesia. Medetomidine (Domitor® Novartis, 1mg/ml) 0.1mg/kg IM and Ketamine (Ketamine®, Parnell Laboratories, Australia) 2-2.5mg/kg IM are a safe and reliable injectable anaesthetic combination in flying foxes. Mask induction with isoflurane and oxygen can also be used. Animals may be intubated, the operators taking great care to avoid being bitten. Handlers should wear gloves at all times.

What Drugs Can Be Used?

Antibiotics

Enrofloxacin (Baytril®50 Antibacterial Injection, Bayer, 50mg/ml; Baytril®25 Antibacterial Oral Solution, Bayer, 25mg/ml)

Reptiles 10mg/kg SC q48 hrs

Mammals 5-10mg/kg SC sid or 5-10mg/kg PO sid

Amoxycillin (Moxylan®, Jurox, 150mg/ml)

Mammals 7-10mg/kg IM sid or 10mg/kg PO bid

Amoxycillin trihydrate (Betamox LA®, Norbrook, 150mg/ml)

Mammals 15mg/kg IM q48hrs

Clindamycin (Antirobe Aquadrops®, Pfizer; Antirobe Capsules®, Pfizer)

Mammals 11mg/kg PO bid

Penicillin (150mg/kg procaine penicillin and 112.5mg/kg benzathine penicillin) q48hrs--cat and dog dose rate

Nystatin (Mycostatin, Nilstat)

5000-10000 U/kg tid for 5 days to counter any secondary fungal or yeast infections during antibiotic therapy.

50,000 U/kg tid for 7 days in the treatment of oral candidiasis

Anthelmintics and Topical Antiparasitic Preparations

Ivermectin (Ivomec®, Merial,10mg/ml)

Reptiles 0.02 ml/kg

Praziquantel 20g/L Oxfendazole 20g/L (Wormout Gel®, Vetafarm)

Reptiles 0.05 ml/100g

Fipronil (Frontline Spray®, Merial, 2.5g/L)

Mammals--stickfast fleas--apply sparingly to fleas with a cotton bud. Also used on dasyurids

Selamectin (Revolution®, Pfizer)--use cat and dog dose rate for sarcoptic mange in wombats

NSAIDs, Analgesics and Anaesthetics

Tolfenamic acid (Tolfedine®, Ausrichter, 40mg/ml)

Reptiles and mammals 4mg/kg IM sid

Meloxicam (Metacam®, Boehringer Ingelheim, 1.5mg/ml)

Reptiles and mammals 0.2mg/kg

Diazepam (Pamlin®, Parnell Laboratories, 5mg/ml)

Mammals--0.5-1 mg/kg

Butorphanol tartrate (Butomidor Injection®, Ausrichter, 10mg/ml)

Reptiles and mammals--0.1-0.4mg/kg IM

Alfaxalone (Alfaxan®-CD RTU, Jurox)--see anaesthetic section

Medetomidine (Domitor®, Novartis, 1mg/ml)

Ketamine (Ketamine® Parnell Laboratories, 100mg/ml)--see anaesthetic section

Disclaimer

Veterinarians treating sick and injured mammals and reptiles should be aware of the risks involved with respect to envenomation and zoonotic disease. Veterinarians should advise clients of the "off label" use of drugs mentioned in this manuscript. The notes are meant as a guide only and advice contained within may change with time.

References

1. Hemsley S (1994) Dermatitis in free-living common brushtail possums (Trichosurus vulpecula). Australian Veterinary Practitioner 24, 147-155.

2. Johnson R, Roffey J (2006) An anatomical approach to prognosis in traumatic injuries of the common eastern long-necked turtle, Chelodina longicollis. Proceedings of the Combined Conference of the Unusual and Exotic Pets Group of the Australian Veterinary Association and the Association of Avian Veterinarians--Australian Committee, Wellington, New Zealand.

3. Johnson R (2006) Dystocia in an injured common eastern long-necked turtle (Chelodina longicollis). Vet Clin North Am Exot Anim Pract.:9(3):575-81.