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Squamous cell carcinoma is a commonly reported neoplasm in avian species. Often locally invasive, it rarely distantly metastasizes. Superficial chronic ulcerative dermatitis (SCUD) is a commonly observed dermatologic condition in companion psittacine birds. This report describes a case of metastatic squamous cell carcinoma in an African gray parrot (Psittacus erithacus) caused by malignant transformation of an initial SCUD lesion that developed over a 2.5-year period. The right humerus was previously amputated to treat a squamous cell carcinoma, but it recurred in the skin 4 months prior to presentation. The bird presented on referral with pelvic limb paresis, and computed tomography showed a large, more right sided, paraspinal mass involving the right caudal coelom and effacing the lungs, ribs, and vertebral canal, resulting in the presenting neurologic signs. The patient was euthanized, and limited necropsy diagnosed the coelomic mass as a squamous cell carcinoma effacing the liver. Though uncommonly reported, squamous cell carcinoma may distantly metastasize to other parts of the body even with partial or seemingly complete excision. SCUD is still a poorly understood condition and should be further researched to determine etiology and find more effective therapies. This is the first report of a metastatic squamous cell carcinoma invading the vertebral canal and spinal cord resulting in upper motor neuron signs in the pelvic limbs. Chronic inflammation may lead to malignant transformation, and once squamous cell carcinoma has developed, the goal of therapy should be complete surgical excision where possible. [ABSTRACT FROM AUTHOR]

Neuropathic pain is a manifestation of chronic pain that arises with damage to the somatosensory system. Pharmacologic treatment recommendations for alleviation of neuropathic pain are often multimodal, and the few reports communicating treatment of suspected neuropathic pain in avian patients describe the use of gabapentin as part of the therapeutic regimen. To determine the pharmacokinetics of gabapentin in Hispaniolan Amazon parrots ( Amazona ventralis), compounded gabapentin suspensions were administered at 30 mg/kg IV to 2 birds, 10 mg/kg PO to 3 birds, and 30 mg/kg PO to 3 birds. Blood samples were collected immediately before and at 9 different time points after drug administration. Plasma samples were analyzed for gabapentin concentration, and pharmacokinetic parameters were calculated with both a nonlinear mixed-effect approach and a noncompartmental analysis. The best compartmental, oral model was used to simulate the concentration-time profiles resulting from different dosing scenarios. Mild sedation was observed in both study birds after intravenous injection. Computer simulation of different dosing scenarios with the mean parameter estimates showed that 15 mg/kg every 8 hours would be a starting point for oral dosing in Hispaniolan Amazon parrots based on effective plasma concentrations reported for human patients; however, additional studies need to be performed to establish a therapeutic dose. [ABSTRACT FROM AUTHOR]

A 37-year-old female yellow-naped Amazon parrot ( Amazona auropalliata) was presented with a history of lethargy, inappetence, and decreased vocalizations. On examination, the coelom was moderately distended and palpated fluctuant, and the heart was muffled on auscultation. Coelomic ultrasound, coelomocentesis, and radiographs were performed and revealed an enlarged cardiac silhouette and marked coelomic effusion. Pericardial effusion was confirmed by echocardiography. A well-circumscribed, hyperechoic soft tissue density was observed at the level of the right atrium on initial echocardiography; however, a cardiac mass was not identified by computed tomography scan or repeat echocardiograms. Ultrasound-guided pericardiocentesis was performed under anesthesia, and cytology results were consistent with hemorrhage; no neoplastic cells were identified. A repeat echocardiogram 4 days after pericardiocentesis revealed recurrence of the pericardial effusion. Due to the grave prognosis, the owners declined endoscopic pericardiectomy, and the patient died the following day. On postmortem examination, the pericardial surface of the heart was covered in a white to yellow, multinodular mass layer. Histologic analysis revealed a multinodular mass extending from the atria, running along the epicardium distally, and often extending into the myocardium. Neoplastic cells present in the heart mass and pericardium did not stain with a Churukian-Schenk stain, and thyroglobulin immunohistochemistry was negative. Cytokeratin and vimentin stains showed positive expression in the neoplastic cells within the mass. These results are consistent with a diagnosis of mesothelioma. This is the first report of mesothelioma in a psittacine bird. [ABSTRACT FROM AUTHOR]

Objective To document intraocular measurements and predict intraocular lens ( IOL) power specific to the bald eagle. Animals studied Eleven adult, captive bald eagles. Procedures Axial globe length ( AGL), anterior chamber depth ( ACD), crystalline lens thickness ( CLT), and the distance from the cornea to the posterior lens capsule ( CPLC) were measured in eight adult bald eagles using B-mode with vector A-mode ultrasound. Keratometry was done on four eagles. Two estimates for postoperative anterior chamber depth ( PACD) were obtained from four aphakic eyes from three eagles by measuring from the apex of the anterior cornea to the center of an imaginary line that would connect the remaining edges of the anterior lens capsule across the capsulorhexis ( PACD1) and from the apex of the anterior cornea to halfway between the anterior and posterior lens capsule ( PACD2). IOL strength was predicted using the Colenbrander, Binkhorst, and Fyodorov theoretical formulas. Results Mean ± SD biometry for phakic eyes was AGL = 26.57 ± 0.45 mm, ACD = 4.45 ± 0.18 mm, CLT = 5.49 ± 0.14 mm, and CPLC = 10.00 ± 0.33 mm. Mean predicted PACD1 was 6.1 ± 0.66 mm, and PACD2 was 6.4 ± 0.70 mm. Mean horizontal and vertical corneal refractive power was 39.91 ± 0.43 diopters (D) and 40.02 ± 0.08 D, respectively. Calculated IOL power ranged from +16.4 to 17.4 D. Conclusions Calculations using ultrasonographic biometry, keratometry, and theoretical IOL formulas suggest that the strength of an IOL necessary to return an aphakic bald eagle to emmetropia is between +16.4 and +17.4 D. [ABSTRACT FROM AUTHOR]

The objectives of this study were to determine reference intervals, perform longitudinal analyses, and determine the index of individuality (IoI) of 8 hematologic, and 13 biochemical and electrophoretic variables for a group of captive bald eagles (Haliaeetus leucocephalus). Reference intervals were determined from blood samples collected during annual wellness examinations for 41 eagles (23 male and 18 female) with ages ranging between 6 and 43 years (18.7 +- 7.4, mean +- SD) at the time of sample coll Please check similar errors throughout the ASAection. Longitudinal analyses and IoI were determined for measured hematologic, biochemical, and protein electrophoretic variables, both individually and as a group, for a subset of 16 eagles (10 male and 6 female) during a 12-year period. This smaller group of eagles ranged in age between 2 and 20 years at the start of the study period, and between 14 and 32 years (21.96 5.0, mean 6 SD) at the end of the study period. Significant increases with age within the group of 16 eagles were observed only for red blood cells, percent heterophils, total protein, and ß-globulin protein fraction, while albumin:globulin decreased significantly with age. A low IoI (>1.4) was determined for all hematologic and biochemical variables except y globulins, which had high IoI (<0.6) for 3 individuals within the subset of 16. [ABSTRACT FROM AUTHOR]

Sixteen adult captive bald eagles (Haliaeetus leucocephalus) underwent a complete bilateral ocular examination to assess normal ocular parameters and describe ophthalmic lesions. Tear production was measured with the Schirmer tear test 1 and intraocular pressure was measured with applanation tonometry. The menace response was normal bilaterally in 13 of 16 eagles. Two birds had normal menace responses despite having fundic lesions, and 2 birds with an inconsistent or absent menace response did not have appreciable ophthalmic lesions. Mean (SD) tear production was 14 ± 2 mm/min (range, 8-19 mm/min). Mean intraocular pressure was 21.5 ± 1.7 mm Hg (range, 15-26 mm Hg). At least 1 ocular lesion was present in 50% of examined eyes. Cataracts, the most common lesion observed, were present in 8 eyes of 5 birds. Three of 4 known geriatric birds were or had been affected with bilateral cataracts. Overall, ocular lesions are common in captive bald eagles, and cataracts appear to be more prevalent in geriatric bald eagles. An obvious positive menace response is present in most visual birds but may be absent in some eagles that are either normal or that do not have appreciable ophthalmic lesions. Applanation tonometry and the Schirmer tear test 1 can be performed easily on adult bald eagles and provide reproducible results. [ABSTRACT FROM AUTHOR]

A 3-year-old male, hybrid mallard duck (Anas platyrhynchos) was presented with a 2-year history of progressive, ascending paresis and paralysis. On presentation, the bird was in sternal recumbency and displayed intermittent focal seizures and intention tremors. Proprioceptive deficits and absent withdrawal reflexes were observed in both pelvic limbs, wing extension was limited, and reflexes were diminished bilaterally. Other findings included emaciation and dehydration. Results of a complete blood count and plasma biochemical analysis revealed anemia, hypoproteinemia, hypoglycemia, and hyperuricemia. Radiographs were unremarkable and results of an Aspergillus antibody were weakly positive. The duck went into cardiopulmonary arrest and died approximately 1 hour after initiating treatment with intravenous crystalloid fluids. A postmortem diagnosis of neuronal ceroid lipofuscinosis (NCL) was made based on the presence of neuronal granular cytoplasmic material that was autofluorescent and stained with periodic acid-Schiff and Luxol fast blue. To our knowledge, this is only the second case report of NCL in an avian species and the first in waterfowl. [ABSTRACT FROM AUTHOR]

Abstract: More so than any other terrestrial vertebrate, birds rely most heavily on their ability to assess their visual environment. High visual acuity is not only necessary to find and acquire food, but also to navigate surroundings, to identify conspecifics and potential mates, and to quickly identify and escape from predators. This article aims to help the reader understand how birds, particularly birds of prey, see by reviewing pertinent anatomy and physiology of the eye, color vision, visual fields, visual acuity, accommodation, and flicker-fusion frequency. For more information on specific disease conditions of the avian eye, the reader is encouraged to review any number of avian medical and surgical texts. [Copyright &y& Elsevier]

The objective of this study was to evaluate the pharmacokinetic properties of ceftiofur crystalline free acid (CCFA) administered intramuscularly at dosages of 10 and 20 mg/kg in bald eagles (BAEAs) (Haliaeetus leucocephalus). Ceftiofur crystalline free acid is a long-acting, injectable, third-generation cephalosporin antibiotic drug. A prospective, randomized, complete crossover design was used for this pharmacokinetic investigation. CCFA (10 or 20 mg/kg) was administered intramuscularly, and blood samples were obtained from 6 adult, nonreleasable, healthy BAEAs at predetermined sampling times. After a 4-week washout period, the protocol was repeated with each bird receiving the dose not given during the initial sample collection according to the randomized crossover design. Plasma ceftiofur free acid equivalents were quantified and data were analyzed by a noncompartmental pharmacokinetic approach. The mean observed peak plasma concentrations were 9.23 µg/mL and 15.08 µg/mL for 10 and 20 mg/kg CCFA IM administration, respectively. The mean observed time to maximum plasma concentration was 18 and 17.6 hours, and the mean terminal elimination half-life was 32.38 and 38.08 hours for intramuscular administration of 10 and 20 mg/kg CCFA, respectively, in the BAEAs. Reported minimum inhibitory concentrations of raptor bacterial isolates from a prior study was used to determine the target minimum inhibitory concentration of 1 µg/mL selected for this investigation. From the previously published information, a target plasma concentration of 4 µg/mL was determined for the CCFA in the BAEAs. From the results of this study, CCFA may be dosed every 60 and 110 hours at 10 mg/kg IM, and every 80 and 160 hours at 20 mg/kg IM in BAEAs. [ABSTRACT FROM AUTHOR]

Milk thistle (Silybum marianum) has been used in humans for the treatment of liver disease because of its antioxidant properties and its ability to stabilize cell membranes and regulate cell permeability. To investigate possible hepatoprotective effects in birds, standardized extracts (80%) of silymarin from milk thistle were tested in white Carneaux pigeons (Columba livia). Pigeons were separated into 3 groups and fed diets formulated to provide milk thistle at a level of 0, 10, or 100 mg/kg body weight per day. After acclimation, the birds were challenged with B1 aflatoxin (3 mg/kg body weight for 2 consecutive days) by oral gavage. Liver function then was assessed by hematologic testing and plasma biochemical analysis, liver histopathology, and hepatobiliary scintigraphy. Results of histopathology and hepatobiliary scintigraphy showed no protective effects from milk-thistle administration. Aflatoxin challenge resulted in hepatic inflammation and necrosis, biliary-duct hyperplasia, and lymphocyte infiltration. All hepatobiliary scintigraphy elements increased significantly after aflatoxin challenge. Bile acid levels and plasma enzyme concentrations of aspartate aminotransferase, lactate dehydrogenase, alanine aminotransferase, and creatine phosphokinase all increased after aflatoxin exposure and were mostly unchanged with consumption of milk thistle. Only birds fed 10 mg/kg body weight milk thistle showed significant reductions in lactate dehydrogenase, alanine aminotransferase, and creatine phosphokinase concentrations after aflatoxin exposure. Our results show that consumption of milk thistle is not associated with hepatoprotective effects against acute B1 aflatoxin exposure in pigeons. [ABSTRACT FROM AUTHOR]