Neurological examination of clinically healthy pigeons (Columba livia domestica), mute swans (Cygnus olor), common buzzards (Buteo buteo), common kestrels (Falco tinnunculus) and northern goshawks (Accipiter gentilis).

BACKGROUND: A neurological examination is essential for determining the localisation of neurological lesions. However, in avian species, quantitative data regarding the practicability and feasibility of neurological tests are very limited. Therefore, the aim of this study was to establish normative data for the neurological examination of clinically healthy birds of different species. METHODS: Forty-two domestic and feral pigeons (Columba livia domestica), 42 mute swans (Cygnus olor), 12 common buzzards (Buteo buteo), 24 common kestrels (Falco tinnunculus) and six northern goshawks (Accipiter gentilis) were examined. All birds underwent a predefined neurological examination. Interobserver variations between three examiners were investigated in 11 pigeons and 11 mute swans. RESULTS: All postural reaction tests, except for the drop and flap reaction in mute swans, provoked a consistent response in pigeons and mute swans, whereas postural reaction tests of the legs in raptors were often not performable. Cranial nerve tests and most of the spinal reflexes revealed variable responses in all birds. The gastrocnemius reflex was not provokable in any bird. Interobserver agreement was almost perfect (Gwet's AC1 coefficient ≥0.81) for 16 of 21 parameters in the examination in pigeons and for 14 of 21 in mute swans. LIMITATIONS: The inclusion of free-ranging birds, which were not used to handling and for which limited information regarding age, history of previous diseases, etc. was available, may have influenced the results. CONCLUSION: The normative neurological examination data provided in this study will help improve clinicians' interpretation of neurological examination results in the respective bird species.

Retrobulbar Adenocarcinoma with Subconjunctival Extension in a Common Buzzard (Buteo buteo).

A free ranging, fledged common buzzard (Buteo buteo) was found with severe feather damage and left periorbital swelling. Clinical examination revealed a 3.0 × 2.5 × 1.5 cm left medial subconjunctival mass. The abnormal tissue extended over most of the left cornea, severely impairing the bird's vision in that eye. Additionally, the left globe was displaced in a temporal direction. Computed tomography revealed the origin of the mass to be retrobulbar tissue. An ultrasound examination of the mass found cystic areas, and a sanguineous fluid was aspirated. Cytological examination of the aspirated fluid revealed numerous erythrocytes and a few round cells with oval nuclei, single large nucleoli, and abundant foamy cytoplasm. After a poor prognosis for rehabilitation to the wild, the bird was humanely euthanatized. A postmortem examination of the bird confirmed the retrobulbar mass with extension around the bulbus. Histological examination of the mass was consistent with an invasive adenocarcinoma, likely arising from the lacrimal glands. Neoplasia in the orbit has occasionally been described in Psittaciformes, but only rarely in birds of prey such as Accipitriformes.

Clinical, pathological and virological aspects of fatal West Nile virus infections in ten free-ranging goshawks (Accipiter gentilis) in Germany.

West Nile virus (WNV), a zoonotic arbovirus, is a new epizootic disease in Germany and caused increasing avian and equine mortality since its first detection in 2018. The northern goshawk (Accipiter gentilis) is highly susceptible to fatal WNV disease and thus is considered as an indicator species for WNV emergence in European countries. Therefore, information regarding clinical presentation and pathological findings is important for identifying suspect cases and initiating further virological diagnostics. Between July and September 2019, ten free-ranging goshawks were admitted to the Small Animal Clinic of the Freie Universität Berlin with later confirmed WNV infection. Clinical, pathological and virological findings are summarized in this report. All birds were presented obtunded and in poor to cachectic body condition. Most of the birds were juveniles (8/10) and females (9/10). Neurologic abnormalities were observed in all birds and included stupor (3/10), seizures (3/10), head tremor (2/10), head tilt (2/10), ataxia (2/10) and monoplegia (2/10). Concurrent diseases like aerosacculitis/pneumonia (7/10), clinical infections with Eucoleus spp. and Trichomonas spp. (3/10), trauma-related injuries (3/10) and myiasis (2/10) were found. Blood analysis results were unspecific considering concurrent diseases. Median time of survival was two days. The most common pathological findings were meningoencephalitis (9/10), myocarditis (8/10), iridocyclitis (8/8) and myositis (7/10). WNV infection was diagnosed by real-time quantitative reverse transcription polymerase chain reaction and confirmed by serology and immunohistochemistry.