CLINICAL AND PATHOLOGIC FINDINGS IN IGUANIDS WITH SODIUM URATE CHOLELITHIASIS.

Four green iguanas (Iguana iguana) and one blue iguana (Cyclura lewisi) from five facilities were diagnosed with sodium urate cholelithiasis. One case was diagnosed antemortem via ultrasonography, and the iguana underwent a choledochotomy for treatment. The other four cases were identified at necropsy. Pathologic hepatic and biliary changes were present in four of the five cases at necropsy. Histologically, four iguanas had hepatic fibrosis, three had bile duct hyperplasia, and one had cholangiohepatitis and pancreaticocholedochitis. Two iguanas had pathologic renal changes. This is the first report of sodium urate cholelithiasis in reptiles. This case series highlights the potential significant clinical disease caused by sodium urate cholelithiasis and the importance of biliary system evaluation. Further investigation is recommended to explore the pathogenesis of reptilian sodium urate cholelith formation.

Cane toad (Rhinella marina) vitamin A, vitamin E, and carotenoid kinetics.

Many amphibian species are threatened with extinction. Understanding their vitamin A (retinol), E (alpha-tocopherol), and carotenoid requirements is vital, as normal levels of these nutrients have a known connection to breeding success with abnormal levels leading to disease. This research examined vitamins A, E, and carotenoids (apocarotenoid, beta-carotene; beta-cryptoxanthin, lutein, zeaxanthin, and esters) concentration kinetics in the liver and plasma of 65 (57.8) cane toads (Rhinella marina) over 4 months supplemented with commercially available invertebrates in human care. Cane toads were opportunistically collected as part of a population control program for use as an amphibian model species. Toads were randomly assigned to one of two diets: treatment 1 was brown house crickets (Acheta domesticus) consuming Mazuri® Hi Calcium Gut Loading Diet without vitamin A or E supplement, plus fresh raw vegetables (carrot/sweet potato); Treatment 2 was the same diet except no vegetables. Ten toads were euthanized on Day 0 to analyze baseline free-ranging liver and plasma metabolites. Six toads consuming each treatment were euthanized on Days 22, 50, and 81, and n = 7 on Day 119 for analysis. Regardless of dietary treatment, most liver and blood metabolites were substantially higher at time 0 than all time points thereafter (p < .05); Ex: liver vitamin A at time 0 was 87.7 ± 16.12 µg/g while Day 119 for treatments 1 and 2 were 11.6 ± 1.19 and 8.2 ± 0.74, respectively. Few statistically significant differences between diets at the same time point were noted (p < .05). The results from this study indicate that additional or alternative diet supplementation may be needed for cane toads (and potentially other amphibians) to mimic their free-ranging diets.

Conservation medicine and One Health in zoos: Scope, obstacles, and unrecognized potential.

Zoo veterinarians and allied professionals have been contributing to conservation medicine (CM) and One Health (OH) activities for more than two decades. Although the Association of Zoos and Aquariums (AZA) considers conservation a key part of its mission, little published material exists about the extent of AZA work in CM/OH or the challenges and opportunities associated with these endeavors. To better understand the current scope of CM/OH in zoos, we surveyed 53 AZA-accredited institutions from April through October of 2016. We obtained information on CM/OH infrastructure, support for expansion in this area, and strategies to overcome perceived obstacles hindering CM/OH from becoming a core AZA activity. Survey results revealed that while most zoos favor greater investment in CM/OH programs, awareness, and understanding of CM/OH across the broader zoo community and public is lacking. The majority of respondents stated that overcoming this challenge is paramount to attaining support for CM/OH initiatives. In spite of these obstacles, survey respondents highlighted many positive developments in CM/OH. We found that 84% of zoos surveyed are actively engaged in CM/OH activities, and 12% house formal CM/OH programs. Another 8% of respondents said their institutions were developing CM/OH programs. Perhaps most noteworthy, we found that zoo size did not have a significant bearing on the financial amount allocated toward an institution's CM/OH activities. This suggests that all zoos, regardless of size, can make meaningful contributions to the growing movement of CM/OH and help redefine the role of zoos within this movement.

URINARY CORTICOSTERONE CONCENTRATIONS IN FREE-RANGING AND MANAGED CANE TOADS (RHINELLA MARINA).

Approximately 40% of amphibian species are threatened with extinction. The welfare of amphibians maintained under managed care as assurance populations is of vital importance to guard against extinction and provide a viable source population for future reintroduction. To manage amphibian species properly ex situ, it is important to understand how stress levels change over time when animals are removed from the wild and placed into managed environments. Corticosterone was analyzed in urine samples from free-ranging cane toads (Rhinella marina, n = 55) in Miami, FL, and under managed care for 22 (n = 48), 50 (n = 11), 81 (n = 25), or 119 (n = 10) days. Concentrations of corticosterone in free-ranging toad urine averaged 1.74 ± 0.195 ng/ml urine specific gravity (sp. gr.), which was greater (P < 0.05) than other time points (day 22: 0.77 ± 0.114 L; day 81: 0.85 ± 0.191 ng/ml sp. gr.; day 119: 0.58 ± 0.093 ng/ml sp. gr.), except day 50 (0.91 ± 0.274 ng/ml sp. gr.), which was not different from free-ranging or managed care values. Thus, corticosterone was lower in cane toads under managed care compared with those sampled in the wild, suggesting that managed care is not a stressor for this species.

Vitamin A values of wild-caught Cuban tree frogs (Osteopilus septentrionalis) and marine toads (Rhinella marina) in whole body, liver, and serum.

Recent issues surrounding captive amphibians are often nutritionally related problems, such as hypovitaminosis A. Although supplementation of frogs with vitamin A is a topic of investigation, the underlying issue is understanding vitamin A metabolism in amphibian species. To develop a range of "normal" vitamin A concentrations for captive amphibians, baseline vitamin A concentrations must be established in wild amphibian species. In this study, two species, Cuban tree frogs (Osteopilus septentrionalis; n = 59) and marine toads (Rhinella marina; n = 20) were collected from the wild as part of an invasive species control program at Zoo Miami, Miami, Florida. Serum, liver, and whole body samples were analyzed for vitamin A content. The Cuban tree frogs showed higher concentrations on average of vitamin A in serum (82.8 ppb), liver (248.3 IU/g), and whole body (5474.7 IU/kg) samples compared with marine toads (60.1 ppb; 105.3 IU/g; 940.7 IU/kg, respectively), but differences were not significant (P = 0.22). What can be considered "normal" values of vitamin A concentrations across different amphibian species requires further investigation. Although all amphibians collected in this study appeared healthy, a larger sample size of animals, with known health histories and diets, may provide stronger evidence of normal expectations.

Comparison of Corticosterone Concentrations in Dermal Secretions and Urine in Free-Ranging Marine Toads (Rhinella marina) in Human Care.

Corticosterone concentrations have been measured in amphibians by collecting blood or urine samples. However, blood sampling is invasive, and urine can be difficult to collect. A novel method of swabbing the skin of an amphibian has been utilized in numerous species but has not been verified in marine toads (Rhinella marina). This pilot study tested dermal swabs as a noninvasive method for collecting and measuring dermal corticosterone secretions. Swabs were used to collect dermal secretion samples from sixty-six free-ranging marine toads collected on Zoo Miami grounds. The subsequent day the toads were shipped to the North Carolina Zoo where dermal samples were collected again. Additional dermal and urine samples were collected on days 9, 15, 32, and 62 under human care to measure corticosterone concentrations. There was no significant correlation (P ≥ 0.05) noted between corticosterone concentrations reported in dermal swabs and those in urine samples at all four of the euthanasia time points or between the corticosterone concentrations reported in either urine or dermal swabs and the weight of the toads. Dermal swab concentrations (ng/mL) were significantly higher (P ≤ 0.05) on the day of capture (0.64 ± 0.03) and the day of arrival (0.67 ± 0.03) than on day 15 (0.47 ± 0.03). The urine corticosterone concentrations decreased while the toads were in human care with a significant decrease (P ≤ 0.05) between days 9 (0.45 ± 0.07) and 32 (0.21 ± 0.06). This study demonstrated that dermal swabs can be used to collect marine toad corticosterone concentration samples.

Migration and Histologic Effects of Visible Implant Elastomer (VIE) and Passive Integrated Transponder (PIT) Tags in the Marine Toad (Rhinella marina).

Passive integrated transponder (PIT) and visible implant elastomer (VIE) tags are commonly used to identify reptiles, amphibians, and fish. Despite reports of good retention rates and little to no negative effect on survival time, migration remains a concern and histologic changes have not been widely evaluated. Fifty-six wild-caught marine toads (Rhinella marina) were marked with a PIT tag in the left caudal thigh and a VIE tag over the right gastrocnemius muscle prior to transport to the North Carolina Zoo. Fourteen toads were then humanely euthanized on day 9, 15, 32, and 62 for postmortem examination and histopathology which were compared to 10 control toads with no tags. All PIT tags were functional and 95% remained at the insertion site with minimal to no histologic changes. Externally, 48% of VIE tags were visible through the skin at the original site of injection under fluorescent or UV light. Upon gross examination of the tissues, VIE tags had an overall retention rate of 62% at the injection site, with similar retention rates across time points. Migrated VIE material was visible grossly and histologically in the kidneys of 98% of toads and along the right leg, proximally and distally, in 25% of toads. VIE material was also found sporadically in mesentery, colon, and free in the coelomic cavity. Histologically, VIE material in the skin was surrounded by minimal to mild granulomatous inflammation while in the kidney it was associated with dilation of the small vessels, edema, and granulomatous nephritis that progressed in severity over time. Based on these findings, the authors recommend the use of PIT tags over VIE tags for identification of adult anurans, when feasible.

Oral eosinophilic granulomas in tigers (Panthera tigris)--a collection of 16 cases.

Oral eosinophilic granulomas were diagnosed in 16 tigers (Panthera tigris). All lesions were located on the hard or soft palate and typically consisted of flat or slightly raised circular ulcers. Histologic features of these lesions were essentially identical to those seen in oral eosinophilic granulomas of domestic cats and dogs. No clinical signs were noted in eight cases, though various degrees of inappetence, excessive salivation, and dysphagia were noted in the other eight tigers. Six cases were not treated. Treatment for the remaining 10 cases centered on corticosteroids and additional treatments included surgical removal, cryotherapy, antibiotics, and chlorpheniramine. Treatment with corticosteroids did appear to be effective in some cases, though lesions would worsen after cessation of therapy and no cases were cured. In addition, three cases developed complications possibly related to this corticosteroid therapy. The etiology of these lesions remains unknown, though an underlying allergic condition is likely.

Conservation of IL-6 trans-signaling mechanisms controlling L-selectin adhesion by fever-range thermal stress.

Fever is associated with improved survival during infection in endothermic and ectothermic species although the protective mechanisms are largely undefined. Previous studies indicate that fever-range thermal stress increases the binding activity of the L-selectin homing receptor in human or mouse leukocytes, thereby promoting trafficking to lymphoid tissues across high endothelial venules (HEV). Here, we examined the evolutionary conservation of thermal regulation of L-selectin-like adhesion. Leukocytes from animals representing four taxa of vertebrates (mammals, avians, amphibians, teleosts) were shown to mediate L-selectin-like adhesion under shear to MECA-79-reactive ligands on mouse HEV in cross-species in vitro adherence assays. L-selectin-like binding activity was markedly increased by fever-range thermal stress in leukocytes of all species examined. Comparable increases in L-selectin-like adhesion were induced by thermal stress, IL-6, or the IL-6/soluble IL-6 receptor fusion protein, hyper-IL-6. Analysis of the molecular basis of thermal regulation of L-selectin-like adhesion identified a common IL-6 trans-signaling mechanism in endotherms and ectotherms that resulted in activation of JAK/STAT signaling and was inhibited by IL-6 neutralizing antibodies or recombinant soluble gp130. Conservation of IL-6-dependent mechanisms controlling L-selectin adhesion over hundreds of millions of years of vertebrate evolution strongly suggests that this is a beneficial focal point regulating immune surveillance during febrile inflammatory responses.