Ophthalmic findings and parameters in Western tiger salamanders (Ambystoma mavortium) from northern Colorado.

OBJECTIVE: The aim of this study was to document ophthalmic examination findings and provide reference values for ocular examinations and diagnostics in clinically normal Western tiger salamanders (Ambystoma mavortium) and to evaluate the mydriatic effect of a topical rocuronium bromide and identify any adverse effects. ANIMALS STUDIED: Sixteen Western tiger salamanders. PROCEDURE: A complete ophthalmic examination, including intraocular pressure via rebound tonometry [iCare® TonoVet (dog-setting) or iCare® TonoVet Plus (dog-setting)], and fluorescein and Rose Bengal stains, was performed. Ocular surface flora culture swabs were collected for microbiology in four salamanders. Rocuronium bromide (50 µL; 0.01 mg) was administered into each eye in three salamanders. Pupil size and constriction ability were evaluated up to 60 min following administration of rocuronium bromide. Distant visual examination and Doppler heart rate were used to monitor for potential adverse effects of rocuronium bromide. RESULTS: Observed ocular abnormalities included lipid keratopathy/keratitis (19%; 3/16), parasitic ophthalmitis (19%; 3/16), and cataracts (6.3%; 1/16). A significant difference was found between tonometry with iCare® TonoVet (11.5 ± 2.7 mmHg) versus TonoVet Plus (15.4 ± 3.7 mmHg) (p = .025). Fluorescein and Rose Bengal stains were negative in all salamanders. Ocular surface microbiology revealed a high incidence of contamination from environmental flora, with the most common isolate being unidentified as Gram-negative nonfermenters (75%; 3/4). No significant change in pupil size or constriction ability was observed with rocuronium bromide. CONCLUSION: This is the first study to document ocular examination findings and diagnostics in captive and wild urodeles and may serve as a reference for clinical assessment and future studies of the Western tiger salamander.

THE EFFECT OF VARIED ENRICHMENT TYPES ON SNAKE BEHAVIOR.

Environmental enrichment is a strategy used to improve the welfare of animals under human care. While enrichment techniques for mammals and birds have been studied extensively, reptilian enrichment has received less attention. There has been an increase in enrichment programs for reptiles in zoological institutions, however many are not accompanied by behavioral studies. Detailed recording of behavioral responses to enrichment is necessary to assess the efficacy of the enrichment type and to determine its utility in various settings. In this study, 18 snakes of multiple species, from two Families (Colubridae, Pythonidae), were exposed to four enrichment types (Humid Hide, Olfactory, Climbing, Suspended Hide). Baseline recordings were conducted prior to the introduction of enrichment. Snakes were recorded for two hours after introduction of each item. Five behavior types were identified based on baseline videos: tongue flicking, climbing, hiding, interacting with transparent boundaries, and utilizing non-enrichment items. Interacting with transparent boundaries was classified as an undesirable behavior, while the other four behaviors were classified as desirable. Changes in climbing and tongue flicking behaviors were noted with introduction of each item- these changes were not statistically significant. The increase in these behaviors may indicate clinical importance, and shows that snakes under human care respond to environmental enrichment. As some snakes showed a reduction in undesirable behaviors when compared to baseline conditions, this may suggest increased welfare during times when enrichment is offered. The extent to which these results can be applied to other species merits further study.

PLASMA CONCENTRATION AND PHARMACODYNAMICS OF INTRAMUSCULAR ADMINISTRATION OF ALFAXALONE IN INDIAN PEAFOWL (PAVO CRISTATUS).

Alfaxalone, a neuroactive steroid with anesthetic properties, is considered safe when used alone or in combination with other drugs for anesthesia at recommended species doses, and its use has been studied in numerous species. The objective of this study was to assess the pharmacokinetics and pharmacodynamics of IM alfaxalone in Indian peafowl (Pavo cristatus; hereafter peafowl). Eight female peafowl from one zoological institution were used. A control blood sample was obtained before administration of either 10 mg/kg (n = 4) or 20 mg/kg (n = 4) alfaxalone. Blood was collected at 5, 10, 15, 30, and 60 min after alfaxalone injection, with monitoring of sedation score, heart rate, and respiratory rate at each time point. Four peahens receiving a 10 mg/ kg dose had subjectively smoother inductions and recoveries, although sedation level was generally scored as low, with no adverse reactions noted. They were considered fully recovered by the 60-min postinjection time point, although measurable alfaxalone plasma concentrations remained present. Four peahens receiving 20 mg/kg IM experienced adverse effects including seizure-like episodes and hypersensitivity to stimuli throughout the study. This dosing group experienced prolonged recoveries consistent with high plasma concentrations (>3,000 ng/ml). Based on these results, use of 20 mg/kg IM alfaxalone as the sole anesthetic agent is not recommended in this species. Further studies should determine whether alfaxalone in conjunction with other anesthetic or analgesic agents could provide better sedation and smoother induction and recovery for peafowl and to assess the pharmacokinetics and pharmacodynamics of alfaxalone in other avian species.

HYDROMETRA IN ROCK HYRAX (PROCAVIA CAPENSIS) UNDER MANAGED CARE.

In zoos, rock hyrax (Procavia capensis) are commonly maintained in groups and population control is necessary. Here we report on hydrometra prevalence in a group of rock hyraxes. Prevalence of hydrometra in this small group (4/8) far exceeds reproductive pathology prevalence previously reported for this species under managed care. Affected females were nulliparous, but had not been contracepted; instead they were maintained as a single-sex group. The first case presented as sudden death and three additional cases were diagnosed antemortem via ultrasound. Two of these underwent ovariohysterectomy to treat the severe hydrometra. The last case was a mild hydrometra and during follow-up exam was found to have spontaneously resolved. Detailed information regarding clinical presentation, diagnostics and surgical techniques are provided.

Spindly leg syndrome in Atelopus varius is linked to environmental calcium and phosphate availability.

Spindly leg syndrome (SLS) is a relatively common musculoskeletal abnormality associated with captive-rearing of amphibians with aquatic larvae. We conducted an experiment to investigate the role of environmental calcium and phosphate in causing SLS in tadpoles. Our 600-tadpole experiment used a fully-factorial design, rearing Atelopus varius tadpoles in water with either high (80mg/l CaCO3), medium (50mg/l CaCO3), or low calcium hardness (20mg/l CaCO3), each was combined with high (1.74 mg/l PO4) or low (0.36 mg/l PO4) phosphate levels. We found that calcium supplementation significantly improved tadpole survival from 19% to 49% and that low calcium treatments had 60% SLS that was reduced to about 15% at the medium and high calcium treatments. Phosphate supplementation significantly reduced SLS prevalence in low calcium treatments. This experimental research clearly links SLS to the calcium: phosphate homeostatic system, but we were unable to completely eliminate the issue, suggesting an interactive role of other unidentified factors.

Selected Emerging Infectious Diseases of Amphibians.

This article updates the understanding of two extirpation-driving infectious diseases, Batrachochytrium dendrobatidis and Batrachochytrium salamandrivorans, and Ranavirus. Experimental studies and dynamic, multifactorial population modeling have outlined the epidemiology and future population impacts of B dendrobatidis, B salamandrivorans, and Ranavirus. New genomic findings on divergent fungal and viral pathogens can help optimize control and disease management strategies. Although there have been major advances in knowledge of amphibian pathogens, controlled studies are needed to guide population recovery to elucidate and evaluate transmission routes for several pathogens, examine environmental control, and validate new diagnostic tools to confirm the presence of disease.

TREATMENT OF ORAL DISEASE IN EIGHT CAPTIVE BENNETT'S WALLABIES (MACROPUS RUFOGRISEUS) BETWEEN 2011 AND 2019: A CASE SERIES.

Oral disease, such as endodontic disease and macropod progressive periodontal disease (MPPD), which can progress to chronic alveolar osteomyelitis (CAO), have been identified as a common source of morbidity and mortality in captive macropods. This case series reviews the diagnosis and treatment of dental disease in eight captive Bennett's wallabies (Macropus rufogriseus) over the course of an 8-yr period (2011-2019) in a zoological collection. Two wallabies were treated at four separate times, for a total of 14 anesthetized dental surgical procedures. Two wallabies died after treatment for dental disease. Endodontic disease, MPPD, and CAO were all identified and treated with extraction. Cases in which disease was identified early and treated aggressively had a good outcome with no return of clinical signs in the affected area. Several cases of extensive CAO were treated successfully with extraction and extensive debridement. One wallaby developed immune-mediated anemia, a suspected adverse drug reaction associated with prolonged administration of intravenous clindamycin.

CLINICAL CONDITIONS FOUND RADIOGRAPHICALLY IN THE FRONT FEET OF RETICULATED GIRAFFE (GIRAFFA CAMELOPARDALIS RETICULATA) IN A SINGLE ZOO.

Front foot radiographs from 22 giraffe (Giraffa camelopardalis reticulata) at one zoo were analyzed to better understand causes of lameness in this giraffe population. The herd had a history of front hoof overgrowth and intermittent lameness. Radiographic findings included distal interphalangeal joint osteoarthritis (OA), distal phalangeal bone (P3) osteitis, P3 fractures, P3 rotation, and sesamoid bone cysts. OA of the distal interphalangeal joint occurred in at least one front foot of 73% (16/22 giraffe) of the herd, and all giraffe had OA by 7 yr of age. Pedal osteitis was present in at least one front foot in 86% (19/22) of the giraffe, starting in animals as young as 1 yr old. P3 fractures were present in 36% (8/22) of the herd. These fractures were near the site of the deep digital flexor attachment and were diagnosed in giraffe as young as 10 yr old. The presence of severe osteitis was associated with the presence of P3 fractures. This study is unique in that a large herd was trained to participate in voluntary front foot radiographs so multiple causes of foot disease could be diagnosed antemortem and without anesthesia. Although the underlying causes of these lesions are likely multifactorial and currently unknown to us, the high prevalence of foot disease in relatively young animals warrants further investigation across zoos. In this study, OA, osteitis, and P3 fractures were common radiographic findings among giraffe that were limping. Subsequent monitoring and management changes suggest that proactive management of foot health can decrease morbidity and mortality in zoo giraffe.

The relationship between spindly leg syndrome incidence and water composition, overfeeding, and diet in newly metamorphosed harlequin frogs (Atelopus spp.).

Spindly Leg Syndrome (SLS) is a persistent animal welfare issue associated with the rearing of amphibians in captivity. We conducted two experiments to investigate the effects of diet, water composition and overfeeding on prevalence of SLS in newly metamorphosed harlequin frogs (Atelopus spp.). In our first experiment, we offered 400 full-sibling tadpoles of Atelopus certus isocaloric diets in treatments of 31%, 37%, 42% and 48% crude protein respectively. Tadpoles fed higher protein diets metamorphosed faster, but the incidence of SLS exceeded 80% in all treatments leading to the conclusion that variation in dietary protein was not responsible for causing SLS. We used 720 full-sibling Atelopus glyphus tadpoles in a second experiment to examine the effects of diet type, water composition and diet ration on SLS. We found that an overall incidence of 58% spindly leg in tadpoles reared in tap water, but reduced to about 10% in water treated by reverse osmosis and then reconstituted. It is possible that the reverse osmosis treatment removed some factor that caused the SLS, or that the reconstitution may have added a mineral lacking in the original tap water. Within tap water treatments, overfeeding tadpoles in tanks increased the incidence of SLS. We recommend further experimental research into this condition to identify the causative factors in the water. Additional research into the nutritional composition of food available to wild tadpoles would be useful in formulating captive diets, that have to date been solely based on surrogate species.

ESTABLISHMENT OF A FIBRINOGEN REFERENCE INTERVAL IN ORNATE BOX TURTLES (TERRAPENE ORNATA ORNATA).

This study sought to establish a reference interval for fibrinogen in healthy ornate box turtles ( Terrapene ornata ornata). A total of 48 turtles were enrolled, with 42 turtles deemed to be noninflammatory and thus fitting the inclusion criteria and utilized to estimate a fibrinogen reference interval. Turtles were excluded based upon physical examination and blood work abnormalities. A Shapiro-Wilk normality test indicated that the noninflammatory turtle fibrinogen values were normally distributed (Gaussian distribution) with an average of 108 mg/dl and a 95% confidence interval of the mean of 97.9-117 mg/dl. Those turtles excluded from the reference interval because of abnormalities affecting their health had significantly different fibrinogen values (P = 0.313). A reference interval for healthy ornate box turtles was calculated. Further investigation into the utility of fibrinogen measurement for clinical usage in ornate box turtles is warranted.

Reptile Hematology.

The basic principles of hematology used in mammalian medicine can be applied to reptiles. The appearances of the blood cells are significantly different from those seen in most mammals, and vary with taxa and staining method used. Many causes for abnormalities of the reptilian hemogram are similar to those for mammals, although additional factors such as venipuncture site, season, hibernation status, captivity status, and environmental factors can also affect values, making interpretation of hematologic results challenging. Values in an individual should be compared with reference ranges specific to that species, gender, and environmental conditions when available.

Reptile hematology.

The basic principles of hematology used in mammalian medicine can be applied to reptiles. The appearances of the blood cells are significantly different from those seen in most mammals, and vary with taxa and staining method used. Many causes for abnormalities of the reptilian hemogram are similar to those for mammals, although additional factors such as venipuncture site, season, hibernation status, captivity status, and environmental factors can also affect values, making interpretation of hematologic results challenging. Values in an individual should be compared with reference ranges specific to that species, gender, and environmental conditions when available.

Location and removal of deslorelin acetate implants in female African lions (Panthera leo).

Contraception is necessary to manage zoo animal populations and to be able to house animals in groups without producing additional unwanted offspring. In felids and canids, an association between exposure to progestins and the occurrence of endometrial and mammary gland pathology has been documented. Therefore, the Association of Zoos and Aquariums (AZA) Wildlife Contraceptive Center recommends the use of deslorelin acetate for long-term contraception in carnivores. Return to cyclicity after deslorelin treatment has been variable; some individuals show ovarian suppression for long periods after the expected end of the deslorelin efficacy. In an attempt to reduce the time to reversal, techniques to locate and remove previous implants are being developed. This report documents the successful implementation of high-frequency ultrasonography in lions (Panthera leo) to locate and direct surgical removal of multiple deslorelin implants placed at least 2 yr previously as well as the return of follicular activity in both females at 7 months post-removal of implants.

Anaplastic mandibular carcinoma in a meerkat (Suricata suricatta).

An 8-yr-old female slender-tailed meerkat (Suricata suricatta) presented with a necrotic sublingual mass and osteolysis of the mandible. After 1 mo of palliative care, the meerkat was euthanized. The mass was diagnosed histologically as an anaplastic carcinoma with extensive rostral mandibular destruction. Immunohistochemistry for vimentin and cytokeratin was validated in this nontypical species and showed that neoplastic cells expressed both mesenchymal and epithelial characteristics, suggestive of a primitive and poorly differentiated tumor. A review of 150 adult slender-tailed meerkat histopathology reports showed a 2% prevalence of orofacial neoplasia, suggesting that oral neoplasms are uncommon in meerkats.

Selected emerging diseases of amphibia.

This review summarizes the most recent updates on emerging infectious diseases of amphibia. A brief summary of Batrachochytrium dendrobatidis history, epidemiology, pathogenesis, life cycle, diagnosis, treatment, and biosecurity is provided. Ambystoma tigrinum virus, common midwife toad virus, frog virus 3, Rana grylio virus, Rana catesbeiana ranavirus, Mahaffey Road virus, Rana esculenta virus, Bohle iridovirus, and tiger frog virus ranaviruses are extensively reviewed. Emerging bacterial pathogens are discussed, including Flavobacter sp, Aeromonas sp, Citrobacter freundii, Chlamydophila sp, Mycobacterium liflandii, Elizabethkingia meningoseptica, and Ochrobactrum anthropi. Rhabdias sp, Ribeiroia sp, and Spirometra erinacei are among several of the parasitic infections overviewed in this article.

Pituitary cystadenoma, enterolipidosis, and cutaneous mycosis in an Everglades ratsnake (Elaphe obsoleta rossalleni).

An 11-yr-old captive-born male Everglades ratsnake (Elaphe obsoleta rosalleni) presented with dysecdysis, hyperkeratosis, and inappetance. Two skin biopsies demonstrated a diffuse hyperkeratosis with both a bacterial and fungal epidermitis. Fusarium oxysporum was cultured from both biopsies and considered an opportunistic infection rather than a primary pathogen. Medical management was unsuccessful, and the snake was euthanized. Histologic findings included a pituitary cystadenoma arising from the pars intermedia, severe intestinal lipidosis, generalized epidermal hyperkeratosis, and lesions consistent with sepsis. It is hypothesized that endocrine derangements from the pituitary tumor may have caused the skin and intestinal lesions.

A fresh look at metabolic bone diseases in reptiles and amphibians.

Metabolic bone diseases (MBDs) are a common presenting complaint in reptiles and amphibians to veterinarians; however, understanding of the causes and diagnostic and treatment options is often extrapolated from human or other mammalian medicine models. Although the roles of UV-B, calcium, phosphorus, and cholecalciferol are better understood in some MBDs, there remain many X factors that are not. Likewise, quantitative diagnosis of MBDs has been difficult not only in terms of staging a disease but also regarding whether or not a condition is present. Treatment options also present challenges in corrective husbandry and diet modifications, medication/modality selection, and dosing/regimen parameters.

Bacterial and parasitic diseases of amphibians.

Whether in private practice or in a zoologic setting, veterinarians of the exotic animal persuasion are asked to work on amphibians. Veterinarians are able to evaluate amphibians thoroughly for medical issues, with infectious diseases at the forefront. Until quite recently, many infectious diseases were unknown or even misdiagnosed as being caused by opportunistic secondary organisms. Although Batrachochytrium dendrobates and viral diseases are in the forefront of research for amphibians, parasitic and bacterial diseases often present secondarily and, occasionally, even as the primary cause. Full diagnostic workups, when possible, can be critical in determining all the factors involved in morbidity and mortality issues in amphibians.

Bacterial and parasitic diseases of selected invertebrates.

Invertebrate medicine is a rapidly advancing aspect of veterinary medicine, although frustrating in its lack of answers and its limitations compared with vertebrate medicine. Because invertebrates make up 98% of animal life, it should be impossible to contain information on their known bacterial and parasitic diseases within a single article. When the focus is placed on those species commonly kept and treated by non-marine veterinarians, the amount of information becomes manageable. Many exotic species had their known diseases and treatments start this way and then advanced to a higher level of understanding. This article stands as an introduction to the parasitic and bacterial diseases of these fascinating creatures for the veterinary practitioner.