Joanna Hedley

Necrotising fungal dermatitis in a group of bearded dragons (Pogona vitticeps).

DERMATOMYCOSIS in reptiles due to the Chrysosporium anamorph of Nannizziopsis vriesii (CANV) is an emerging disease that is commonly reported in the USA and has more recently been reported in lizards in Spain ([Pare and others 1997][1], [Mitchell and others 2006][2], [Abarca and others 2009][3]).

Partial ear canal ablation and lateral bulla osteotomy in rabbits

Six lop rabbits were presented with clinical signs of otitis media or externa. The presence of disease was confirmed by computerized tomography examination, with two rabbits suffering from bilateral disease. The rabbits were anaesthetized and underwent surgery of the affected bulla. Rabbits with bilateral disease had a minimum of 2 weeks between procedures. A single vertical incision was made over the base of the vertical canal, which was bluntly dissected free from surrounding tissue. The ventral portion of the vertical canal was removed and a lateral bulla osteotomy was performed. The mucosa at the base of the dorsal vertical canal was apposed and the aural cartilage sutured to form a blind-ending pouch open at the pretragic incisure. Histopathological samples taken from the dorsal margin of the vertical canal yielded subtle and non-specific changes in the six samples submitted. All rabbits were discharged within 48 hours of surgery. The cosmetic outcome was excellent with animals retaining visually normal aural anatomy. The partial ear canal ablation/lateral bulla osteotomy procedure is quick and has a good cosmetic result when performed in rabbits.

Husbandry risk factors associated with hock pododermatitis in UK pet rabbits (Oryctolagus cuniculus)

Pododermatitis, often called ‘sore hocks’, is a chronic, granulomatous, ulcerative dermatitis which most commonly affects the plantar aspect of the caudal metatarsal and tarsal areas. Pododermatitis is a common clinical finding in the pet rabbit population, but no data is available regarding the actual prevalence of this condition in the UK pet rabbit population or possible husbandry-related factors which may predispose pet rabbits to development of this condition. It was the aim of this study to determine the prevalence of pododermatitis within a sample pet rabbit population, and study possible correlations with husbandry, sex, breed and origin of the rabbits. Findings suggested that young rabbits are at a lower risk of pododermatitis compared with older rabbits; female domestic rabbits are more predisposed to pododermatitis than males; and 100 per cent of the neutered females examined showed clinical evidence of pododermatitis. The effect that different types of bedding may have on the prevalence of pododermatitis was also investigated. This study also produced a scoring system which can be used to score clinical cases. Our study is of clinical importance because it helps to recognise many of the factors which predispose pet rabbits to pododermatitis, representing the first step towards increased awareness of this extremely common problem.

Reptile haematology and biochemistry

Interpreting haematology and biochemistry results from reptiles is notoriously difficult, due at least in part to the lack of data for many species and the wide variation in reference ranges for others. This article describes sampling techniques in reptilian species and discusses what different parameters mean in terms of physiological status and the indication of particular diseases.

The effects of UV light on calcium metabolism in ball pythons (Python regius)

Despite the popularity of keeping snakes in captivity, there has been limited investigation into the effects of UV radiation on vitamin D levels in snakes. The aim of this study was to investigate the effects of UV-b radiation on plasma 25-hydroxyvitamin D3 levels and ionised calcium concentrations in ball pythons (Python regius). Blood samples were taken from 14 ball pythons, which had never been exposed to UV-b light, to obtain baseline 25-hydroxyvitamin D3 levels and ionised calcium concentrations. Blood samples were then taken again from the same snakes 70 days later after one group (Group 1, n=6 females) were exposed to UV-b radiation daily, and the other group (Group 2, n=5 males and 3 females) were exposed to no UV-b radiation. Mean±sd 25-hydroxyvitamin D3 levels on day 0 in Group 1 were 197±35 nmol/l, and on day 70 were 203.5±13.8 nmol/l. Mean±sd 25-hydroxyvitamin D3 levels in Group 2 on day 0 were 77.7±41.5 nmol/l, and on day 70 were 83.0±41.9 nmol/l. Mean±sd ionised calcium levels at day 0 were 1.84±0.05 mmol/l for Group 1, and on day 70 were 1.78±0.07 mmol/l. Mean±sd ionised calcium levels at day 0 were 1.79±0.07 mmol/l for Group 2, and on day 70 were 1.81±0.05 mmol/l. No association was demonstrated between exposure to UV-b radiation and plasma 25-hydroxyvitamin D3 and ionised calcium concentrations. These results may provide baseline parameters for future studies in this and other snake species to determine ability to utilise UV-b light for vitamin D production.

Use of arterial blood gas analysis as a superior method for evaluating respiratory function in pet rabbits (Oryctolagus cuniculus)

A retrospective study compared invasive (arterial blood gas analysis) and non-invasive (capnography and pulse oximetry) methods of monitoring respiratory function in conscious rabbits. Arterial samples from 50 healthy dwarf lop rabbits, presenting for routine surgical neutering, were analysed on a point-of-care blood gas analysis machine. Reference intervals were obtained for pH (7.35–7.54), PaCO2 (mm Hg) (25.29–40.37), PaO2 (mm Hg) (50.3–98.2), base excess (mmol/l) (6.7–6.5), HCO3 (mmol/l) (17.96–29.41), TCO2 (mmol/l) (18.9–30.5). SaO2 (per cent) (88.8–98.0), Na (mmol/l) (137.6–145.2), K (mmol/l) (3.28–4.87), iCal (mmol/l) (1.64–1.94), glucose (mmol/l) (6.23–10.53), haematocrit (per cent) (23.3–40.2) and haemoglobin (mg/dl) (7.91–13.63). Pulse oximetry (SPO2) and capnography (ETCO2) readings were taken concurrently. There was no statistically significant relationship between SPO2 and SaO2 with a mean difference between SPO2 and SaO2 of 8.22 per cent. There was a statistically significant relationship between ETCO2 vs PaCO2, but a wide range of ETCO2 values were observed for a given PaCO2. The mean difference between these was 16.16 mm Hg. The study has provided reference intervals for arterial blood gas analysis in rabbits and demonstrated that capnography and pulse oximetry readings should not be relied upon in conscious rabbits as a guide to ventilation and oxygenation.

Cloacal prolapses in reptiles: a retrospective study of 56 cases

OBJECTIVES To review the types of cloacal prolapses seen in reptiles and to investigate potential risk factors which may be associated with the presence of a cloacal prolapse. METHOD Retrospective review of medical records of all reptile cases evaluated at the Royal (Dick) School of Veterinary Studies between 1999 and 2013; only cases which had a history of cloacal prolapse were included in the study. RESULTS Prolapses were identified in 56 of 3019 (1·9%) reptiles examined over the study period. Prolapses were 3·47 times as likely in chelonians and lizards compared to snakes. There were no statistically significant differences between the prevalence of prolapses in males and females. Females were 7·5 times more likely to present with a true cloacal prolapse involving no other organs compared to males, and were 4·83 times more likely to present with a prolapse of the colon. CLINICAL SIGNIFICANCE These results suggest that cloacal prolapses are not a common occurrence but that species and sex may both influence the prevalence and type of cases seen.

Gastrointestinal parasitic burdens in UK tortoises: a survey of tortoise owners and potential risk factors

Despite gastrointestinal parasites being commonly diagnosed in captive tortoises throughout the UK, there is a lack of data regarding the prevalence. The aims of this study were to investigate the prevalence of gastrointestinal parasites in tortoises in the UK, and to investigate the factors affecting the prevalence of these parasites. Owners were invited to submit a faecal sample from their tortoise in conjunction with a completed questionnaire covering details of signalment and husbandry. Data from the questionnaires were analysed at the end of the study. Faecal analysis was performed on samples from Testudo hermanni, Testudo graeca and Testudo horsfieldii. This involved examination of direct wet preparations, a modified McMaster technique, passive NaCl flotation and Cryptosporidium staining. Of the 142 samples used, 130 were examined by the first three methods. 49 per cent were positive for one or more parasites. Of the positive samples, 67 per cent were positive for oxyurids, 28 per cent were positive for ascarids and 28 per cent were positive for protozoa (Balantidium, Nyctotherus or flagellates). Only 1/113 (0.8 per cent) samples was positive for Cryptosporidium. The most important risk factors for parasites were sex (F) and length of time (<5 years) in owners possession. This survey showed that gastrointestinal parasites are frequently detected in the faecal samples of captive tortoises in the UK, but their prevalence may be influenced by various factors including sex, length of time owned, age and species.

Critical care of the rabbit

Although rabbits are an increasingly popular household pet, they still retain their wild instincts. From the veterinary surgeons point of view, the most important of these is the tendency of rabbits to hide signs of illness – critical for the survival of a prey species, but unhelpful in a consulting room. Consequently, any rabbit noticed as being ‘sick’ by an owner is often a much more critical patient than a dog or cat with similar problems. This article describes the steps that must be taken when a critically ill rabbit is presented for treatment, and provides some examples of the type of emergency cases that might be seen.

Computed tomography of ball pythons (python regius) in curled recumbency

Anesthesia and tube restraint methods are often required for computed tomography (CT) of snakes due to their natural tendency to curl up. However, these restraint methods may cause animal stress. The aim of this study was to determine whether the CT appearance of the lungs differs for ball pythons in a curled position vs. tube restraint. Whole body CT was performed on ten clinically healthy ball pythons, first in curled and then in straight positions restrained in a tube. Curved multiplanar reformatted (MPR) lung images from curled position scans were compared with standard MPR lung images from straight position scans. Lung attenuation and thickness were measured at three locations for each scan. Time for positioning and scanning was 12 ± 5 min shorter for curled snakes compared to tube restraint. Lung parenchyma thickness and attenuation declined from cranial to caudal on both straight and curled position images. Mean lung parenchyma thickness was greater in curled images at locations 1 (P = 0.048) and 3 (P = 0.044). Mean lung parenchyma thickness decreased between location 1 and 2 by 86-87% (straight: curled) and between location 1 and 3 by 51-50% (straight: curled). Mean lung attenuation at location 1 was significantly greater on curled position images than tube restraint images (P = 0.043). Findings indicated that CT evaluation of the lungs is feasible for ball pythons positioned in curled recumbency if curved MPR is available. However, lung parenchyma thickness and attenuation in some locations may vary from those acquired using tube restraint.