Hearing Assessment of Free-Ranging Owls and Implications for Wildlife Rehabilitation: 31 Cases (2014-2023).

Owls, members of the avian order Strigiformes, are nocturnal birds of prey that are found worldwide except for Antarctica. Traumatized, free-ranging owls are commonly presented to veterinary hospitals and wildlife rehabilitation facilities with the goal of providing medical care and rehabilitation to enable release back into their natural habitat. Minimal guidelines exist for the release of wildlife, and whereas a need for functional vision is described in raptors, assessing and evaluating hearing is usually not mentioned. This can be problematic for nocturnal predators because hearing is the primary sense utilized by owls when hunting and navigating in their dark environment. The brainstem auditory evoked response (BAER) test is a minimally invasive, objective assessment of hearing commonly used in companion animals. To the authors' knowledge, routine or standardized BAER evaluation has not been reported in traumatized, free-ranging owls. In the following retrospective study, 31 free-ranging owls presented to the University of Georgia Veterinary Teaching Hospital for known or suspected trauma or being found in a debilitated state underwent BAER testing to assess for the presence of complete sensorineural hearing loss. Similar to assessment of hearing in companion animals, the BAER test was elicited using a broad click stimulus delivered at 85 dB nHL. In all owls, qualitative assessment and peak latency measurements of the BAER test reflected hearing ability. This study highlights the importance of hearing in nocturnal raptors, how BAER testing can aid in decision making regarding rehabilitation, and provides a foundation for further investigation of hearing loss in traumatized owls. We suggest that veterinarians working with free-ranging owls in a rehabilitation setting should consider BAER testing as part of routine diagnostic testing.

Antemortem Diagnosis and Successful Long-term Management of Disseminated Intracoelomic Xanthogranulomatous Disease in an Eclectus Parrot (Eclectus roratus).

A 12-year-old male eclectus parrot (Eclectus roratus) was referred for evaluation of coelomic distention. Computed tomography and blood work revealed coelomic effusion with free coelomic mineral-attenuating material and elevations in the bile acids and aspartate aminotransferase activity, respectively. Coelomic effusion was consistent with macrophagic inflammation with abundant intracellular lipids. Initial treatment with meloxicam resulted in minimal patient improvement. Disseminated xanthogranulomatous inflammation was suspected based on imaging and diagnostic laboratory results, which were consistent with those previously reported. Biopsy samples of liver tissue and intracoelomic masses confirmed this diagnosis. Treatment was initiated with prednisolone 1 mg/kg/d for 6 months, followed by 0.5 mg/kg/d for 3 months. Clinical improvement was assessed based on owner evaluation, plasma bile acid concentrations, and repeated computed tomographic scans. After 2 months of treatment, the owner reported improved behavior and appetite; this persisted throughout treatment and when the bird was reexamined 17 months following the cessation of steroid therapy. Bile acid concentrations were normal 10 months after the prednisolone therapy was discontinued. Diagnostic imaging showed minimal coelomic effusion 10 months after the last prednisolone dose was administered, with improved ventilation of the air sacs and static to improved dystrophic mineral foci. This report describes the antemortem diagnosis and treatment of disseminated coelomic xanthogranulomatous disease in a psittacine species, with an observed measurable therapeutic response.

Unusual cases of chlamydiosis in psittacine birds.

Avian chlamydiosis is a common disease found in domesticated and nondomesticated avian species caused by several species of chlamydiae including but not limited to Chlamydia psittaci, Chlamydia avium, Chlamydia gallinacea, Chlamydia buteonis, and Chlamydia ibidis. Generally, early in the disease course, birds present with mild nonspecific clinical signs associated with gastrointestinal and respiratory tract disease. During end-stage disease, birds may present in a severe state of emaciation, dehydration, and/or acute death with no known history of prior illness. Between 2000 and 2009, 14 unusual cases of avian chlamydiosis were submitted to the California Animal Health and Food Safety Laboratory System. Histologic lesions noted in the 14 birds included meningoencephalomyelitis (3 of 13, 23%), otitis media (3 of 8), bursitis (9 of 11, 81%), nephritis (8 of 13, 61%), and orchitis (1 of 8). Corresponding immunopositive chlamydiae intracytoplasmic inclusions were detected in all tissues. Positive immunolabeling was detected in optic nerves (5 of 10, 50%), meninges (5 of 13, 38%), and endothelial cells (14 of 14, 100%) in the absence of significant microscopic lesions. This study highlights unusual gross, histological, and immunohistochemical findings of chlamydiosis in psittacines and highlights the importance of a thorough diagnostic approach when confirming or excluding chlamydiosis in psittacine birds.

Intralipid Emulsion Therapy for the Treatment of Suspected Toxicity in 2 Avian Species.

Intravenous lipid emulsion (ILE) therapy has shown promise as a treatment option for a variety of lipophilic toxins. Two birds presented for suspected ingestion of a toxic substance. A blue-and-gold macaw (Ara ararauna) presented after chewing a block of bromethalin rodenticide without overt clinical signs at the time of presentation. Additionally, a free-ranging bald eagle (Haliaeetus leucocephalus) was found weak and depressed near a municipal landfill after presumptive ingestion of pentobarbital. Both birds were treated with ILE therapy for potential intoxication without any adverse events. The macaw was clinically normal after 3 days of hospitalization and at a 1-week reevaluation. The eagle was transferred to a rehabilitation center after markedly improved mentation and strength and was released 7 days later. Clinicians should consider ILE therapy for the treatment of lipophilic toxicities; however, monitoring is recommended for persistent lipemia and other adverse effects that have been reported in the veterinary literature.

Prevalence and Risk Factors of Avian Chlamydiosis Detected by Polymerase Chain Reaction in Psittacine Birds in Thailand.

This study surveyed avian chlamydiosis, with the aim to estimate the prevalence and potential risk factors associated with Chlamydia psittaci infection in psittacine birds kept as domestic pets in Thailand. Oropharyngeal swabs were collected from 120 psittacine birds that were randomly selected from hospitals in the central (Bangkok) and northeastern regions (Khon Kaen) of Thailand between 2019 and 2021. The oropharyngeal swabs were subject to polymerase chain reaction testing to detect the C psittaci ompA gene. The prevalence of C psittaci was 2.5% (3/ 120, 95% confidence interval = 0.3-5.3). Of the 3 positive birds, 1 was a Forpus parrot (Forpus species)(CP43TH) and 1 was an African grey parrot (Psittacus erithacus)(CP49TH) from Bangkok; both were juvenile birds with clinical signs of disease. The third positive bird (CP12TH) was a subclinical adult sun conure (Aratinga solstitialis) from Khon Kaen. Two sequences of samples that were previously identified in human psittacosis cases (accession numbers MK032053.1 and HM450409.1) were also examined. Since there was a low number of infected birds, potential associations between C psittaci infection and various environmental variables (eg, cage cleaning, synanthropic birds, quarantine of new birds, and overcrowding) were assessed by Fisher exact tests. This study provides estimates of the prevalence and potential risk factors associated with C psittaci infection in psittacine birds from central (Bangkok) and the northeastern regions (Khon Kaen) of Thailand. The detection of C psittaci in captive psittacine birds demonstrates that there is a possibility for bird-to-bird transmission as well as some zoonotic potential for the human caretakers of these birds. Furthermore, larger-scale studies should be conducted to confirm these findings.

Visceral Haemoproteus minutus Infection in a Major Mitchell's Cockatoo (Lophochroa leadbeateri).

A 1-year-old major Mitchell's cockatoo (Lophochroa leadbeateri) was presented for evaluation of weakness, diarrhea with undigested seeds in the droppings, and weight loss. Leukocytosis with severe heterophilia, monocytosis, and lymphocytosis was noted on the complete blood count. Altered plasma biochemical parameters included a slight increase in creatine kinase and mild hypoproteinemia. Two blood smears before and after 2 days of treatment revealed mild polychromasia and anisocytosis but no blood parasites. Radiographic and computed tomographic imaging of the cockatoo were helpful in identifying airsacculitis, pneumonia, and gastrointestinal motility disorders. The patient died 5 days after treatment for the presenting clinical problems. On the gross postmortem examination, dark red foci in the ventricular muscle layers and 1-3-mm white foci in the myocardium, opaque air sacs, and dark lungs were identified. Histopathologic examination of submitted tissue samples found severe granulomatous ventriculitis and myocarditis with intralesional Haemoproteus species megalomeronts. Qualitative polymerase chain reaction testing for the cytochrome b (cyt b) gene performed on pooled heart, liver, kidney, and intestinal tissues identified 99.5% homology to Haemoproteus minutus. This case report demonstrates the expansion of the geographic range of H minutus to France and potentially to Belgium, which may compromise breeding and conservation of Australian parrots living outdoors. Challenging diagnosis, rapid disease progression, and the absence of validated treatment protocols for psittacine patients suggest that the use of preventive measures to reduce the presence of insect vectors such as hippoboscid flies and biting midges (Culicoides) should be considered. Haemoproteus minutus should be considered and potentially screened by polymerase chain reaction testing on blood samples, especially in the case of highly susceptible avian species (eg, Australian parrots in Europe) that present with sudden weakness, heterophilic leukocytosis, and monocytosis associated with mild anemia.

Determining the Prevalence of Avian Chlamydiosis in Wild Amazona Species From Brazil Using Molecular Testing and Clinical Signs.

Avian chlamydiosis is a disease that occurs in birds, especially parrots, and is caused by the Gram-negative bacterium Chlamydia psittaci. Wild Animal Screening Centers in Brazil receive, maintain, treat, and place (preferably to nature) wild animals recovered from illegal trafficking. We performed molecular testing for avian chlamydiosis in parrots from the genus Amazona that were presented to these centers. Cloacal swab samples were collected from 59 parrots (Amazona species) and transported in aqueous or culture medium. The samples were subsequently submitted for DNA extraction by the boiling method, polymerase chain reaction (PCR) amplification using CPF/CPR primers, and agarose gel electrophoresis. Conjunctivitis, nasal discharge, and poor body condition were the clinical signs associated with a differential disease diagnosis of avian chlamydiosis. Transport medium did not have an effect on the test results. The prevalence of C psittaci in the samples was 37% (22/59, 95% confidence interval: 25-49). There was a significant (P = 0.009) association between the PCR test results and clinical signs. Follow-up testing was conducted on a subgroup of 14 individuals that initially tested negative on PCR; 50% (7/14) of these birds were found to be positive within 24 days of the first test. The results of this study confirm the feasibility of using the CPF/CFP primer-based PCR to detect C psittaci in Amazona species, describe a less costly method of transporting biological material for DNA extraction, and evaluate the temporal aspect for obtaining positive results through molecular testing for C psittaci in Amazona species.

A multiplex real-time PCR assay for differential identification of avian Chlamydia.

Avian chlamydiosis is an acute or chronic disease of birds after infection by Chlamydia. Although Chlamydia psittaci is the primary agent of the disease, two additional species, Chlamydia avium and Chlamydia gallinacea, have also been recognized as potential disease agents. Therefore, the diagnosis of avian chlamydiosis requires differential identification of these avian Chlamydia species. The objective of the present study was to develop a multiplex real-time polymerase chain reaction (PCR) assay to rapidly differentiate between these three species of avian Chlamydia (C. psittaci, C. avium, and C. gallinacea) as well as to detect the genus Chlamydia. Specific genetic regions of the three species were identified by comparative analysis of their genome sequences. Also, the genus-specific region was selected based on 23S rRNA sequences. PCR primers and probes specific to the genus and each species were designed and integrated in the multiplex real-time PCR assay. The assay was highly efficient (94.8-100.7%). It could detect fewer than 10 copies of each target sequence of the genus and each species. Twenty-five Chlamydia control and field DNA samples were differentially identified while 20 other bacterial strains comprising 10 bacterial genera were negative in the assay. This assay allows rapid, sensitive, and specific detection of the genus and the three species of avian Chlamydia in a single protocol that is suitable for routine diagnostic purposes in avian diagnostic laboratories.

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.

A novel RFLP method for identification of morphologically similar avian Sarcocystis species.

Protozoans of genus Sarcocystis are widespread parasites infecting mammals, birds, and reptiles. Morphology of their sarcocysts is an important criterion for species identification. However, as more and more morphologically similar Sarcocystis species are being found and described, additional methods for their routine diagnostics are needed. We investigated restriction fragment length polymorphism (RFLP) as potential alternative to sequencing data analysis for the identification of Sarcocystis species using birds as an intermediate host. The internal transcribed spacer 1 (ITS1) region sequences of seventeen Sarcocystis species (S. albifronsi, S. anasi, S. calchasi, S. columbae, S. cornixi, S. corvusi, S. cristata, S. halieti, S. falcatula, S. fulicae, S. kutkienae, S. lari, S. lindsayi, S. rileyi, S. turdusi, S.wenzeli, and S. wobeseri) of interest were analysed and five best-fitting endonucleases generating most informative restriction fragments were selected for routine testing. In general, RFLP analyses are always inconclusive as they target very short DNA sequences. However, it can be an irreplaceable technique when fast and cheap identification and discrimination of known species are required, which was our main goal and preliminary results indicate that RFLP could be successfully used when identifying closely related avian Sarcocystis species with just two nucleases.

Adaptation of the classical end-point ITS-PCR for the diagnosis of avian trichomonosis to a real-time PCR reveals Bonelli's eagle as a new host for Trichomonas gypaetinii.

Avian trichomonosis is a parasitic disease caused mainly by Trichomonas gallinae and other Trichomonas species. It can be asymptomatic, or it can produce a necrotic lesion in the upper digestive tract and spread to other organs, causing the death of the infected birds. In this study, we aimed to evaluate an adapted real-time PCR method for the diagnosis of different genotypes and species of avian oropharyngeal trichomonads. Fifty-six samples from the oropharynx of Bonelli's eagles (Aquila fasciata) obtained between 2018 and 2019 were analyzed using the real-time PCR and the end-point PCR, both targeting trichomonads ITS, and the results were compared by a coefficient of agreement. All positive samples were sequenced. The analysis showed a higher percentage of detection of real-time PCR ITS compared with end-point PCR ITS (64.3 vs 55.4%), and good agreement value (Kappa = 0.816). Melting temperature value for resulting amplicons of real-time PCR for avian trichomonads was 83.45 ± 0.72 °C. Genotypes A, D, and III were found among the sequences. Moreover, Trichomonas gypaetinii, a common species in scavenger birds, is reported for the first time in Bonelli's eagles.

Untangling the actual infection status: detection of avian haemosporidian parasites of three Malagasy bird species using microscopy, multiplex PCR, and nested PCR methods.

The development of new molecular methods has significantly improved the detection and identification of avian haemosporidian parasites (Plasmodium, Haemoproteus and Leucocytozoon) compared to microscopic examination. Very large numbers of previously hidden Haemosporida species of a wide range of avian hosts have thus been discovered in the last two decades. However, test parameters of the various detection methods remain largely unevaluated. In this study, the merits of microscopy, multiplex PCR, and nested PCR were compared to identify the infection status of three Malagasy bird species. A total of 414 blood samples of Hypsipetes madagascariensis, Foudia omissa and F. madagascariensis, as well as 147 blood smears, were examined for haemosporidian infection. Thirty-four lineages of haemosporidian parasites could be identified, of which six have been detected for the first time. Microscopy, multiplex and nested PCR showed differences in detection rate, most likely due to low parasitemia of chronically infected birds. The combination of both PCR methods yielded the best results. In particular, detection of multiple infections could be greatly improved and will enable more precise prevalence estimates of individual haemosporidian species in wild birds in the future.

EVALUATION OF CLINICAL DIAGNOSTICS FOR PROVENTRICULAR NEMATODIASIS DUE TO SYNHIMANTUS NASUTA IN LORIKEETS (TRICHOGLOSSUS SPP.).

In this case series, clinical investigations were pursued during a Synhimantus nasuta infection in a lorikeet (Trichoglossus spp.) flock outbreak situation to better describe and document clinical presentations. In 11 lorikeets suspected to be infected with Synhimantus based on at least one abnormal finding on their physical examination (lethargy, feather-damaging behavior on the ventrum, weight loss, pale iris), the presence of five additional parameters was documented: anemia, relative eosinophilia, increased proventricular diameter-to-keel height ratio (PKR), proventricular barium filling defect, and positive fecal occult blood detection test. A total score (X of 9) was calculated by combining all these findings. Synhimantus nasuta infection was confirmed in four of these individuals by modified Wisconsin fecal examination. Suspected cases (n = 7 of 11) presented only with low scores (1-3 of 9), whereas birds with confirmed infections (n = 4 of 11) presented with both low (1-3 of 9, n = 2 of 4) and high (6-7 of 9, n = 2 of 4) total scores. High scores were associated with clinical anemia. Fecal occult blood was present in all confirmed cases and 4 of 7 suspected cases. An enlarged proventriculus was only observed in birds with active shedding (n = 3 of 4). Follow-up evaluations after 6 mon of treatment with ivermectin and selamectin suggested complete recovery with lowered or normalized total scores. In conclusion, during an S. nasuta outbreak, a rapid physical examination helps to identify suspect cases, including individuals requiring immediate medical attention. In the absence of ova shedding, infection cannot be excluded on the basis of scarce clinical findings, but the detection of occult fecal blood and an increased PKR should raise the index of suspicion.

Cardiac Disease of Raptors.

Cardiac disease, in its various presentations, is being recognized as a common raptor health problem. Evidence suggests that the prevalence of cardiac disease varies between captive and wild bird of prey populations, probably because of differences in activity levels and diet. However, a wide variety of cardiovascular diseases have been reported to affect raptor species (captive and free living), including atherosclerosis, pathogenic arrhythmias, infectious cardiomyopathies, and endocarditis. Diagnostic testing used to identify cardiac abnormalities include radiographic imaging, electrocardiogram, echocardiogram, and computed tomography angiograms. Information pertaining to therapeutic treatment for raptor cardiac disease patients is inadequate or has not been investigated. This review of cardiac disease will provide current information regarding cardiac diseases that are diagnosed in birds of prey, diagnostic testing, and treatment options.

Liposarcoma of Probable Medullary Bone Origin in a Lovebird (Agapornis roseicollis).

A 15-year-old female peach-faced lovebird (Agapornis roseicollis) was presented to the hospital for a possible left wing injury and an inability to fly after falling in its cage. On physical examination the left elbow was swollen and painful. Radiographic images revealed left wing soft tissue swelling surrounding the elbow and lysis of the distal humerus with extensive cortical thinning. Subsequent high-definition volumetric-imaging 3-dimensional computed tomography (HDVI 3D CT) revealed a pathological fracture, cortical lysis, periosteal reaction, and abnormal intraosseous soft tissue of the left humerus with associated soft tissue swelling, suggestive of neoplasia. No evidence of metastatic disease was identified. Surgical amputation of the left wing was elected. A liposarcoma and pathologic fracture of the humerus were diagnosed histologically and by oil red O staining for lipids in the neoplastic cells. The morphologic features of the tumor suggested that it developed within the adipocyte component of the medullary bone. The incision at the amputation site healed without complication. A follow-up HDVI 3D CT performed 4 months postsurgery showed no evidence of metastatic disease. To the authors' knowledge, this is the first report of a primary liposarcoma of medullary bone origin in an avian species.

Salivary Gland Adenoma in a North Island Brown Kiwi (Apteryx mantelli).

A 7-month-old male North Island brown kiwi (Apteryx mantelli) was transferred from a European zoological park to a North American private aviary. The bird appeared clinically normal upon arrival, but within 30 days, it developed clinical disease signs of sneezing, stridor, and increased respiratory effort. Upon examination a 1-mm yellow plaque was identified on the glottis. After 14 days of empiric treatment with enrofloxacin, meloxicam, and itraconazole, on repeat examination, the glottal plaque had increased in size to a 7-mm-diameter friable mass attached to the right laryngeal cartilage and was partially obstructing the airway. Initially, 80% of the mass was manually dislodged, but within 4 days the tissue mass had again enlarged to approximately 3 mm × 4 mm × 4 mm, prompting surgical excision. On histopathologic examination, the mass was identified as a benign salivary gland adenoma without clear margins. Approximately 3 years postexcision, there is no evidence of tumor regrowth. The successful excision of a benign salivary tumor described in this report will serve as a valuable guide for future cases of similar neoplasms diagnosed in the oral cavity of kiwis and other avian species.

Treatment of Recurrent Multifocal Cutaneous Squamous Cell Carcinoma in an African Grey Parrot (Psittacus erithacus) with Intralesional Carboplatin in Poloxamer 407.

A 16-year-old male Congo African grey parrot (Psittacus erithacus) was presented with an ulcerated wing mass that was excised and diagnosed on histopathology as squamous cell carcinoma (SCC). A second surgery was performed to completely excise the tumor margins, resulting in over 5 years of remission for the neoplasm. However, over the next 6 years the patient developed SCC in 3 new locations on the body, as well as 2 squamous papillomas. The 2 papillomas were surgically excised and did not recur. Due to their size and location, none of the 3 new SCCs were amenable to complete excision. Instead, the 3 SCCs were managed with a series of treatments with intralesional carboplatin in poloxamer 407 and carbon dioxide surgical laser debridements. This treatment regimen has resulted in long-term (52 months, 30 months, and 17 months) resolution for all 3 of the SCCs. The overall survival time for the patient, from the initial diagnosis to the time of this report, is over 2900 days. While being treated for the 3 SCCs, the African grey parrot had no overt signs of complications or adverse side effects.

Identification of the avian tracheal trematode Typhlocoelum cucumerinum (Trematoda: Cyclocoelidae) in a host-parasite-environment system: diagnosis, life cycle and molecular phylogeny.

Typhlocoelum cucumerinum is a tracheal parasite of birds widely distributed across the globe. Nevertheless, aspects of the biology of this cyclocoelid are still poorly understood. Herein, we report the finding of T. cucumerinum in definitive and intermediate hosts from an urban waterbody of Brazil. The parasite was initially detected during the necropsy of domestic Muscovy ducks (Cairina moschata) found dead in the locality. Coproparasitological tests in live animals revealed that 12/47 (25.53%) Muscovy ducks and 2/8 (25%) mallards (Anas platyrhynchos platyrhynchos) were infected with T. cucumerinum. Moreover, rediae and metacercariae morphologically similar to T. cucumerinum were found in 3/248 (1.33%) Biomphalaria straminea collected in the same waterbody frequented by the birds. The conspecificity between the adult and the larval stages was confirmed molecularly (100% similarity in Cox-1). Moreover, the phylogenetic position of T. cucumerinum was determined for the first time based on partial fragments of the 28S, Cox-1 and Nad-1 genes. The species grouped with other members of the subfamily Typhlocoelinae with sequences available, but the data obtained do not support the distinctiveness of the genera Typhlocoelum and Tracheophilus. Further studies involving a broader range of species can result in taxonomic rearrangements in Typhlocoelinae.

Lymphoma in Psittacine Birds: A Histological and Immunohistochemical Assessment.

In psittacine birds, round cell neoplasms that originate from lymphocytes, plasma cells, histiocytes, or mast cells are sporadic and poorly described. The lack of morphological and immunohistochemical diagnostic criteria or grading schemes make specific diagnoses and prognoses challenging. We assessed cases of psittacine birds diagnosed with round cell neoplasia from 3 North American veterinary diagnostic laboratories to describe the diagnostic features of these tumors. For all cases, demographic data, anatomic distribution, histological features, and immunoreactivity for T (CD3) and B (Pax5 and MUM-1) cell markers were assessed using tissue microarrays and whole slide mounts. Thirty-eight psittacine birds representing 14 species were included. Tumors were mainly infiltrative and multicentric, were composed of homogenous sheets of round to polygonal cells, and commonly presented with a high mitotic count (average 21 mitoses per high-power field). Based on Pax5 immunoreactivity, B-cell lymphoma was most common (19/38 [50%]), and was significantly associated with involvement of the gastrointestinal and urogenital systems. Of the 38 cases, 6 (16%) were consistent with T-cell lymphoma, 3 (8%) with plasma cell tumor, and 3 (8%) were double-reactive for both B- and T-lymphocyte markers. This is the first study to describe morphologic and immunohistochemical features of round cell neoplasia in a large number of psittacine birds, and provides benchmark data for future studies aimed at elucidating the diagnosis and prognosis of these neoplasms. These data also provide useful information about reactivity of commercially available antibodies as lymphocyte markers in tissues of multiple psittacine species.

Antemortem diagnosis of congenital glaucoma in a white-bellied caique (Pionites leucogaster).

A 34-day-old, male, white-bellied caique (Pionites leucogaster) was presented for a complaint of bilateral buphthalmos. Clinical examination was unremarkable apart from the ophthalmic findings. The ophthalmologic examination was negative for direct, consensual, and dazzle reflexes in both eyes. The intraocular pressure exceeded 40 mm Hg OU. Fluorescein stain demonstrated corneal surface lesions suggestive of exposure keratopathy subsequent to bilateral buphthalmos. Diagnostic imaging tests were conducted to perform ocular biometric measurements and investigate the intraocular structures, including the iridocorneal angle and lens, by means of high-resolution ultrasonography (HRUS). The presence of congenital glaucoma in this young parrot was strongly suspected after clinical and ophthalmological examination and the results of diagnostic imaging. Pharmacological treatment to reduce intraocular pressure was initiated using dorzolamide hydrochloride 2% and timolol maleate 0.5%. A month later, the parrot's eyes did not show any visual improvement, but the intraocular pressure had returned to normal. The parrot was unable to feed itself and died during a feeding procedure. Postmortem examination revealed ab ingestis pneumonia. Both eyes were submitted for histopathology, with severe anterior segment dysplasia and goniodysgenesis found OU. Histological findings added to the clinical presentation, the ophthalmologic examination and the imaging findings, confirmed the presence of congenital glaucoma.