Prevalence and risk factors of hepatic lipid changes in bearded dragons (Pogona vitticeps).

Hepatic lipidosis is a common disease of captive bearded dragons (Pogona vitticeps). Diagnosis, prevention, and treatment of this condition are challenging, as there is minimal information in the literature. Our study determined the prevalence and epidemiological risk factors associated with the grade and severity of hepatic lipid changes in bearded dragons submitted for necropsy in 2 North American institutions. A total of 571 postmortem cases were retrieved, and from each pathology report the demographic data (age, sex) and the list of final diagnoses were extracted. For each case diagnosed with hepatic lipidosis, the archived sections of liver were reviewed and the severity of lipid change was stratified using a standardized histologic grading system. Descriptive statistics were used to estimate the prevalence of each grade and severity class. Associations between grade and severity, as well as demographic data and concurrent diseases, were explored using ordinal logistic regression analysis. On multiple logistic models, the occurrence of infectious disease and neoplasia was associated with decreased grade and severity of hepatic lipid changes, while the female sex and adult age were associated with an increased grade and severity. None of the other variables were significantly associated with hepatic lipid changes. These results suggest that reproductively active females and adult bearded dragons are predisposed to increasing hepatic lipid changes, while those with an underlying disease process have reduced hepatic lipid accumulation and changes, possibly due to increased fat catabolism. Data in this study can serve to benchmark the prevalence of hepatic lipidosis in bearded dragons and allow further investigations.

Morphological features of hepatic lipid changes in bearded dragons (Pogona vitticeps), and a proposed grading system.

Hepatic lipidosis is commonly diagnosed in pet bearded dragons (Pogona vitticeps). However, there are no studies detailing the histological features of hepatic lipid changes in this species. This study describes the microscopic features of lipid change and details an associated scoring system. Histologic hepatic sections were retrospectively evaluated from 252 bearded dragons submitted for necropsy. Pathologic assessment was used to develop a grading scheme with 2 qualitative, 1 quantitative, and 6 semi-quantitative microscopic parameters, which were refined based on variability. The final grading system developed for diffuse and panlobular lipid accumulation included 2 semi-quantitative and 1 quantitative categories: percentage of hepatocellular vacuolation, fibrosis, and hepatocellular swelling, respectively. Hepatocellular swelling was indirectly quantified by counting the number of nuclei per unit area. There was a strong positive correlation (P < .001) between the percentage of hepatocellular vacuolation and lipid content, a strong negative correlation (P < .001) between nuclear count and lipid content, and a moderate correlation (P < .001) between fibrosis and lipid content. Each category was given a numerical value ranging from 0 to 4, with the sum of each representing the final grade. Cutoff values stratified microscopic changes into mild (final grade 1-4), moderate (5-7), and severe (≥8). There was strong interrater agreement for assessment of vacuolization, fibrosis, and severity classification and moderate for hepatocellular swelling. This study documents the features of hepatic lipid changes in bearded dragons. Although a cutoff to differentiate pathologic from nonpathologic lipid accumulation could not be estimated, the proposed grading scheme can be used to inform future studies.

MAST CELL NEOPLASIA IN THE GREEN IGUANA, IGUANA IGUANA.

This case series is the first description of mast cell neoplasia in green iguanas, Iguana iguana. All iguanas were adults. Six were females, and four were males. Lesions were associated with the oral cavity in 3 of 10 cases, and on the head in 3 of 10 cases. Three of the cases had masses over the trunk; a single case had a lesion on a limb. Single masses were most common involving the face or oral cavity (6 of 10), whereas four cases with neoplasia distributed along the trunk had multiple masses. One case developed peripheral blood mastocytosis. In most neoplasms, cells contained metachromatic granules in toluidine blue-stained sections. Polymerase chain reaction identified no internal tandem duplication mutation in exon 11 of c-kit, but a mutation in exon 8 in a single case. Compared with other reptiles, green iguanas may be predisposed to development of mast cell neoplasia.

AIR SAC TREMATODES (CYCLOCOELIDAE STOSSICH, 1902) INFECTING BIRDS IN ZOOLOGICAL INSTITUTIONS IN THE UNITED STATES.

Air sac trematodes (Digenea: Cyclocoelidae) were detected in 23 avian species from eight aviaries in the United States. Most of the infected host species were passeriform birds, but a few species in other orders also were infected. Four species of adult flukes were encountered: Circumvitellatrema momota, Morishitium sp., Psophiatrema greineri, and Szidatitrema yamagutii. Findings from retrospective review of medical records, necropsy records, and author observations are presented. Potential terrestrial snail intermediate hosts were collected from three indoor aviaries. A high prevalence (47%) of larval trematode infections was demonstrated in one species of nonnative snail (Prosopeas achatinacea); one larva was isolated and matched to the adult species (C. momota) from birds using PCR. Problems with introducing potentially infected wild-caught birds into aviaries, and exchanging captive individuals between aviaries where they potentially may carry infections, are discussed.

Neuropathology of feral conures with bromethalin toxicosis.

Bromethalin is a widely used neurotoxic rodenticide sometimes affecting nontarget wildlife. However, the effects of bromethalin on avian species are largely unknown. Here, we report the neuropathology of 14 feral conures (Psittacara sp.) with bromethalin toxicosis. Clinically, all birds presented with different degrees of paraparesis that sometimes progressed to dysphagia, ataxia, and tetraparesis. Histologically, there was astrogliosis, pallor, and vacuolation of white matter in the brain. This was usually more prominent in the medial longitudinal fasciculus, pons, optic tectum, cerebellar peduncle, and ventral funiculus. In most affected areas, there was loss of oligodendrocytes, and axons had extensive myelin loss or marked intramyelinic edema with splitting of myelin sheaths at the intraperiod line. Conures with bromethalin toxicosis had neuropathological changes similar to those of mammals exposed to bromethalin but with a characteristic distribution, probably related to higher susceptibility to cytotoxic edema in certain regions of the avian brain.

Disseminated coelomic xanthogranulomatosis in eclectus parrots (Eclectus roratus) and budgerigars (Melopsittacus undulatus).

Xanthogranulomatosis is an inflammatory lesion characterized by lipid-containing macrophages, extracellular lipid, hemorrhage, and necrosis. We describe disseminated intracoelomic xanthogranulomatosis in 5 eclectus parrots (Eclectus roratus) and 2 budgerigars (Melopsittacus undulatus). Postmortem, clinicopathologic, and historical case material was reviewed. Ages ranged from 3 to 24 years; there were 5 males and 2 females. Table food was included in the diet of 3/5 cases, and animal products were included in 2/3 cases. Common clinicopathologic abnormalities included leukocytosis (4/5 cases) and elevated concentrations of bile acids (3/4 cases) and cholesterol within 6 months prior to death (2/4 cases). At postmortem examination, all 7 birds had grossly visible, irregular, soft, tan to yellow, amorphous plaques distributed on the surfaces of the viscera and body wall. Histologic evaluation and oil red O stain revealed xanthogranulomatous inflammation with phagocytized and extracellular lipid, necrosis, cholesterol clefts, fibrosis, and mineralization. Infectious agents were not identified with special stains in all cases. Concurrent hepatobiliary disease was present in 6/7 cases, and 6/7 had lipid accumulation within the parenchyma of various visceral organs. Five cases had atherosclerosis of great vessels. We describe a unique form of disseminated coelomic xanthogranulomatosis in 2 psittacine species. This condition should be recognized as a differential diagnosis in cases of disseminated coelomic mass formation and coelomic distension in psittacine birds, particularly in eclectus parrots and budgerigars.

Diagnosis of Seminoma With Metastasis to the Brain and Kidneys in a Moluccan Eclectus (Eclectus roratus) Using Advanced Contrast Based Imaging.

A 20-year-old male Moluccan eclectus (Eclectus roratus) was presented with a history of falling off the perch, ataxia, unilateral blindness, hyporexia, and progressive lethargy. The eclectus was found to have a leukocytosis (52 × 103 cells/µL), characterized by an absolute and relative heterophilia (42.6 × 103 cells/µL and 82%, respectively), relative lymphopenia (18%), elevated bile acids (88 µmol/L), and elevated triglycerides (236 mg/dL). Radiographic images revealed a mass effect within the caudal coelom. After 13 days of outpatient supportive care, the patient was rechecked and had normalized bile acids (<35 µmol/L), static triglycerides (232 mg/ dL), and hyperuricemia (18.6 mg/dL). Computed tomography was performed antemortem with and without iodinated contrast agent, 4 mL/kg IV over 2 minutes, and a mass was found associated with the left kidney. Due to worsening neurologic signs and involvement with surrounding structures, the owner elected euthanasia. Before the postmortem examination, a postmortem intravascular contrast agent was used to provide a more thorough visualization of internal anatomical structures, including left renal vasculature disruption, mass vasculature, caudal coelomic organ displacement, and increased irregular optic chiasm radiodensity. Postmortem, a 4 × 4.1 × 5.1-cm white to tan mass was identified. Histopathology confirmed a seminoma with metastasis to the kidneys and optic chiasm. Seminomas have been described in avian species; however, seminoma metastasis in an eclectus parrot confirmed by histopathology has not been reported, and optic chiasm metastasis of a seminoma has not been described in any avian species. This report describes postmortem computed tomographic angiography of metastatic seminoma in a Moluccan eclectus with metastasis to the optic chiasm.

Giant Cell Sarcomas in Domestic Rabbits (Oryctolagus cuniculus).

Multinucleated giant cells (MGCs) are a prominent histological feature of various mesenchymal neoplasms and are often considered a criterion of malignancy. Mesenchymal neoplasms with MGCs for which the cell lineage is unclear generally are referred to as giant cell sarcomas. Here we characterize the gross, histologic, and immunohistochemical features of 90 giant cell sarcomas in domestic pet rabbits. Based on the anatomic location and histologic and immunohistochemical findings, 18 cases were classified as histiocytic sarcomas (HS) and 72 cases as anaplastic sarcomas (AS). At postmortem examination, HS was either localized HS (n = 7) always affecting the lungs, or disseminated HS (n = 10) that affected the lungs (n = 10), liver (n = 6), kidneys (n = 4), pleura (n = 2), mediastinum (n = 2), heart (n = 4), skeletal muscle (n = 1), adipose tissue (n = 1), and lymph node (n = 1). Additionally, one cecal biopsy was consistent with HS. Microscopically, HS were characterized by sheets of neoplastic polygonal to round cells that contained single to several, often greatly enlarged nuclei as well as abundant cytoplasm. HS were always positive for CD204 and always negative for SMA and desmin. In contrast, AS arose most commonly from the skin or subcutis (n = 62) and rarely the skeletal muscle (n = 8) or abdominal organs (n = 2). In 29% of extra-abdominal AS, the tumor deeply invaded into surrounding connective tissue, skeletal muscle, tendons, and bone causing pathological fractures. Five of 9 postmortem cases metastasized to various organs often including the lungs. Microscopically, AS were characterized by sheets of spindle or pleomorphic cells admixed with variable numbers of MGCs. Immunohistochemically, AS were always negative for CD204 and often (71%) positive for SMA and/or desmin.

Retrospective Review of Mycobacterial Conjunctivitis in Cockatiels (Nymphicus hollandicus).

The etiologic disease organism responsible for causing mycobacteriosis in avian species is an acid-fast gram-positive bacterium. This bacterium causes granulomatous disease in various internal organs, but in cockatiels (Nymphicus hollandicus) it has been commonly identified within the conjunctival tissues. Twenty-six cases of mycobacterial conjunctivitis in cockatiels were diagnosed through histopathologic assessment of diseased tissue samples, Fite acid-fast staining, and polymerase chain reaction in this retrospective study. Clinicians who saw these cases were contacted, and information was obtained regarding recommended treatment protocols prescribed for the patients, the Mycobacterium species identified, and case outcomes. All patients in this retrospective study had a biopsy performed on the affected conjunctival tissue, and because of the small size of the patients, this excisional biopsy removed the affected tissue in its entirety or significantly debulked the lesion. Of the 26 cases, 10 were lost to follow-up, 4 were euthanatized, 7 died, and 5 were alive at the time this information was submitted for publication.

Lipid-Related Lesions in Quaker Parrots ( Myiopsitta monachus).

The Quaker parrot has been used as a psittacine model to study clinical lipidology and lipid-related disorders. However, while Quaker parrots appear to be anecdotally susceptible to a variety of spontaneous dyslipidemic disorders and lesions caused by excess lipid accumulation, epidemiologic data are lacking. A multicenter retrospective study on 652 pathology submissions (411 necropsies and 243 biopsies) from Quaker parrots was performed by recording the final pathological diagnoses, age, and sex for each bird. The prevalence of lesions associated with lipid metabolism, such as hepatic lipidosis, atherosclerosis, xanthomas, adipose tumors, coelomic steatitis/steatonecrosis, endogenous lipid pneumonia, and acute pancreatic necrosis/pancreatitis, was reported. Multiple logistic regression models were used to characterize the effects of sex and age on these lesions, and the prevalence of hepatic lipidosis and atherosclerosis was compared to those in a random sample of control psittacine birds. The raw prevalence of atherosclerosis and hepatic lipidosis was 5.6% (95% confidence interval [CI], 3.4%-7.8%) and 21.2% (95% CI, 17.2%-25.1%), respectively. While the prevalence of atherosclerosis was similar to other psittacine species, hepatic lipidosis was more common in Quaker parrots. Quaker parrots also showed a unique susceptibility to acute pancreatic necrosis with a prevalence of 12.9% (95% CI, 9.7%-16.1%). Male parrots were found to be more susceptible than females to lipid accumulation lesions ( P = .0024), including atherosclerosis ( P = .018) and hepatic lipidosis ( P < .001). This retrospective study confirms the high susceptibility of Quaker parrots to lipid-related disorders and presents epidemiological data that may be useful to avian clinicians, pathologists, and researchers using Quaker parrots.

Surgical Management of an Intrathoracic Branchial Cyst in a Yellow-crested Cockatoo (Cacatua sulphurea).

A 40-year-old, female lesser crested cockatoo (Cacatua sulphurea) was presented with a complaint of hyporexia and sudden onset of sneezing and wheezing. Physical examination revealed mild stertorous inhalation, and the apex of the heart was palpable caudoventral to the distal tip of the sternum. Projection radiographic images showed a soft tissue mass displacing the heart and the thoracic portion of the trachea. A subsequent computed tomography series revealed a single, large, and predominantly encapsulated soft-tissue mass. The mass was contained within the cranial thoracic region and occupied most of the anatomic location of the thoracic portion of the clavicular air sac, extending around a portion of the trachea. A surgical exploratory procedure was performed, with a thoracic inlet thoracotomy, and the mass was found to be cystic and deeply attached to surrounding tissues at its caudal-most aspect. Complete excision was not possible, and the mass was drained and an incomplete resection was accomplished with approximately one-half of the cystic structure removed and submitted for histopathology. The mass was found to be benign, epithelial-lined, dense, fibrous connective tissue that would be consistent with a branchial cyst.

Four cases of iridociliary tumors in domestic rabbits (Oryctolagus Cuniculus).

Spontaneously occurring ocular neoplasia is rarely reported in rabbits. This case series presents four cases of rabbits diagnosed with iridociliary tumors, which have not been previously reported in this species. Major pathological findings include epithelial tumors affecting the anterior uvea with variable pigmentation and basement membrane formation. Follow-up information was only available for two cases, but neither showed evidence of metastasis, suggesting that the prognosis for these tumors in rabbits, as in other species, may be very good.

Widespread recombination, reassortment, and transmission of unbalanced compound viral genotypes in natural arenavirus infections.

Arenaviruses are one of the largest families of human hemorrhagic fever viruses and are known to infect both mammals and snakes. Arenaviruses package a large (L) and small (S) genome segment in their virions. For segmented RNA viruses like these, novel genotypes can be generated through mutation, recombination, and reassortment. Although it is believed that an ancient recombination event led to the emergence of a new lineage of mammalian arenaviruses, neither recombination nor reassortment has been definitively documented in natural arenavirus infections. Here, we used metagenomic sequencing to survey the viral diversity present in captive arenavirus-infected snakes. From 48 infected animals, we determined the complete or near complete sequence of 210 genome segments that grouped into 23 L and 11 S genotypes. The majority of snakes were multiply infected, with up to 4 distinct S and 11 distinct L segment genotypes in individual animals. This S/L imbalance was typical: in all cases intrahost L segment genotypes outnumbered S genotypes, and a particular S segment genotype dominated in individual animals and at a population level. We corroborated sequencing results by qRT-PCR and virus isolation, and isolates replicated as ensembles in culture. Numerous instances of recombination and reassortment were detected, including recombinant segments with unusual organizations featuring 2 intergenic regions and superfluous content, which were capable of stable replication and transmission despite their atypical structures. Overall, this represents intrahost diversity of an extent and form that goes well beyond what has been observed for arenaviruses or for viruses in general. This diversity can be plausibly attributed to the captive intermingling of sub-clinically infected wild-caught snakes. Thus, beyond providing a unique opportunity to study arenavirus evolution and adaptation, these findings allow the investigation of unintended anthropogenic impacts on viral ecology, diversity, and disease potential.

Organ weights and histopathology of double-crested cormorants (Phalacrocorax auritus) dosed orally or dermally with artificially weathered Mississippi Canyon 252 crude oil.

A series of toxicity tests were conducted to assess the effects of low to moderate exposure to artificially weathered Deepwater Horizon Mississippi Canyon 252 crude oil on representative avian species as part of the Natural Resource Damage Assessment. The present report summarizes effects of oral exposure (n=26) of double-crested cormorants (DCCO; Phalacrocorax auritus) to 5 or 10ml oil kg-1 day-1 for up to 21 days or dermal application (n=25) of 13ml oil to breast and back feathers every three days totaling 6 applications in 21 days on organ weights and histopathology. Absolute and relative kidney and liver weights were increased in birds exposed to oil. Additionally, gross and/or histopathologic lesions occurred in the kidney, heart, pancreas and thyroid. Clinically significant renal lesions in the orally dosed birds included squamous metaplasia and increased epithelial hypertrophy of the collecting ducts and renal tubules and mineralization in comparison to controls. Gross cardiac lesions including thin walls and flaccid musculature were documented in both orally and dermally dosed birds and myocardial fibrosis was found in low numbers of dermally dosed birds only. Cytoplasmic vacuolation of the exocrine pancreas was noted in orally dosed birds only. Thyroid follicular hyperplasia was increased in dermally dosed birds only possibly due to increased metabolism required to compensate damaged feather integrity and thermoregulate. Gastrointestinal ulceration was found in orally dosed birds only. There were no significant hepatic histopathologic lesions induced by either exposure route. Therefore, hepatic histopathology is likely not a good representation of oil-induced damage. Taken together, the results suggest that oral or dermal exposure of DCCOs to artificially weathered MC252 crude oil induced organ damage that could potentially affect survivability.

MYCOBACTERIUM GENAVENSE IN AN AFRICAN PENGUIN (SPHENISCUS DEMERSUS).

A 19-yr-old female African penguin (Spheniscus demersus) presented with labored breathing and anorexia. Radiographs revealed soft-tissue density lesions in the left lung fields and fluid in the right. The penguin died during the night. Postmortem examination demonstrated multiple granulomas in the lungs and air sacs. The right coelom was filled with opaque fluid. Histopathology of the lung, liver, kidney, and spleen identified Mycobacterium as a primary disease etiology. Large numbers of acid fast-positive, rod-shaped bacteria were recognized on tissue staining. Mycobacterium genavense was detected by polymerase chain reaction (PCR) using primers specific for the species. Further confirmation of M. genavense was accomplished using PCR with universal Mycobacterium spp. primers followed by sequencing of the amplicon obtained. To our knowledge, this is the first reported case of mycobacteriosis-and specifically M. genavense -in an African penguin. This case also demonstrates the similarities of presentation between the more commonly suspected and encountered aspergillosis and mycobacteriosis.

Isolation of a Bohle-like iridovirus from boreal toads housed within a cosmopolitan aquarium collection.

A captive 'survival assurance' population of 56 endangered boreal toads Anaxyrus boreas boreas, housed within a cosmopolitan collection of amphibians originating from Southeast Asia and other locations, experienced high mortality (91%) in April to July 2010. Histological examination demonstrated lesions consistent with ranaviral disease, including multicentric necrosis of skin, kidney, liver, spleen, and hematopoietic tissue, vasculitis, and myriad basophilic intracytoplasmic inclusion bodies. Initial confirmation of ranavirus infection was made by Taqman real-time PCR analysis of a portion of the major capsid protein (MCP) gene and detection of iridovirus-like particles by transmission electron microscopy. Preliminary DNA sequence analysis of the MCP, DNA polymerase, and neurofilament protein (NFP) genes demonstrated highest identity with Bohle iridovirus (BIV). A virus, tentatively designated zoo ranavirus (ZRV), was subsequently isolated, and viral protein profiles, restriction fragment length polymorphism analysis, and next generation DNA sequencing were performed. Comparison of a concatenated set of 4 ZRV genes, for which BIV sequence data are available, with sequence data from representative ranaviruses confirmed that ZRV was most similar to BIV. This is the first report of a BIV-like agent outside of Australia. However, it is not clear whether ZRV is a novel North American variant of BIV or whether it was acquired by exposure to amphibians co-inhabiting the same facility and originating from different geographic locations. Lastly, several surviving toads remained PCR-positive 10 wk after the conclusion of the outbreak. This finding has implications for the management of amphibians destined for use in reintroduction programs, as their release may inadvertently lead to viral dissemination.

Diagnosis and treatment of diffuse large B-cell lymphoma in an orangutan (Pongo pygmaeus).

Lymphoma is a common malignancy observed in companion animals. This type of naturally occurring neoplasia has been uncommonly reported in great apes. Diffuse large B-cell lymphoma was diagnosed in an 8-yr-old captive orangutan (Pongo pygmaeus) with gastrointestinal disease by histologic and immunohistochemical methodologies. The orangutan was treated with three cycles of combination chemotherapy (intravenous Rituxan, cyclophosphamide, doxorubicin, and vincristine). The primate has been in good health and exhibiting normal behaviors for more than 15 mo following treatment.

Osteosarcoma of the tibiotarsus with possible pulmonary metastasis in a ring-necked dove (Streptopelia risoria).

An unknown-age, adult female ring-necked dove (Streptopelia risoria) was presented with an ulcerated mass on the medial side of the right tibiotarsus. Radiographs revealed severe boney lysis with proliferative periosteal reaction. Surgical amputation was performed at the level of the mid femur and histopathologic examination of the mass identified an osteosarcoma. At the 6-month recheck, the bird was in good condition with no evidence of tumor regrowth or metastasis; however, at 8 months, the dove was found dead. On necropsy, a large mass was present in the coelomic cavity invading the left pulmonary parenchyma. Histopathologic examination indicated a spindle cell sarcoma. Immunohistochemical staining for osteocalcin and osteonectin was performed on the confirmed osteosarcoma in the tibiotarsus and the spindle cell sarcoma mass. Results indicated positive intracytoplasmic immunoreactivity for osteocalcin and osteonectin in the confirmed osteosarcoma neoplasm. Very rare positive cytoplasmic immunoreactivity occurred in the spindle cell sarcoma.

Gastrointestinal cryptosporidiosis in captive psittacine birds in the United States: a case review.

Histopathologic analysis performed on tissue samples from 34 captive psittacine birds over a 14-year period demonstrated gastrointestinal cryptosporidiosis. Although 8 birds had died unexpectedly, at least 10 showed gastrointestinal signs before death. Most birds had other significant pathologic lesions, unrelated to cryptosporidiosis, in which case Cryptosporidium was likely a secondary pathogen. However, in 11 birds the only significant histopathologic finding was gastrointestinal cryptosporidiosis. In 2 lovebird (Agapornis species) cases, direct sequencing of proventricular samples confirmed the presence of Cryptosporidium avian genotype III. A description and analysis of the pathologic findings in these 34 birds, as well as a review of avian gastrointestinal cryptosporidiosis, is provided.