Evaluation of Thermal Antinociceptive Effects of Intramuscular Hydromorphone Hydrochloride in Great Horned Owls (Bubo virginianus).

Across the Americas, great horned owls (Bubo virginianus) are often presented to veterinarians for conditions requiring pain management. Although recent studies have evaluated opioid drugs in raptor species, information in Strigiformes is lacking. The objective of this study was to evaluate the analgesic effect and duration of action of hydromorphone hydrochloride, a full µ-opioid receptor agonist, in great horned owls. In a randomized, blinded, balanced crossover study, 6 adult birds (5 females and 1 male) received hydromorphone (0.3 and 0.6 mg/kg) or saline (0.9% NaCl) solution (0.03 mL/kg; control) in the left pectoral muscle, with a 7-day washout interval between treatments. Each bird was assigned an agitation-sedation score, and the thermal foot withdrawal threshold (TFWT) was measured at predetermined times before (t = 0 hours) and after treatment administration (t = 0.5, 1.5, 3, and 6 hours). Measurements of the TFWT were obtained with a test box equipped with a thermal perch, which delivered a gradually increasing temperature 40-62°C (104-143.6°F) to the right plantar surface of the owl's foot. Compared with controls, hydromorphone at 0.3 mg/kg dose resulted in significantly higher mean TFWT at 0.5 hours (P < 0.001), 1.5 hours (P = 0.003), and 3 hours (P = 0.005), whereas the 0.6 mg/kg dose resulted in significantly higher mean TFWT from 0.5 hours (P = 0.035) to 1.5 hours (P = 0.001). Both hydromorphone doses were associated with a significant change in the agitation-sedation score (P = 0.001), consistent with mild to moderate sedation. Two owls were observed tremoring after administration of the 0.6 mg/kg dose, which was not noted after the 0.5-hour timepoint; no other adverse effects were identified. This study offers scientific evidence to support the use of a µ-opioid agonist in great horned owls for pain management. Pharmacokinetics and other pharmacodynamic studies of other pain models evaluating hydromorphone and other opioid drugs in this species are still needed.

Blood Transfusion from a Magellanic Great Horned Owl (Bubo virginianus magellanicus) to a Barn Owl (Tyto alba): A Successful Case of Xenotransfusion.

This report describes successful transspecies blood transfusion from a Magellanic horned owl (Bubo virginianus magellanicus) to a barn owl (Tyto alba). The barn owl was admitted to a wildlife rehabilitation center with severe anemia (packed cell volume [PCV] = 6.7%) from suspected anticoagulant rodenticide poisoning. Procedures performed included patient stabilization, pharmacological treatment, and persistent monitoring following the blood transfusion. The patient's PCV was measured daily, increasing progressively, and attaining a normal value for the species (PCV > 40%) on the eighth day posttransfusion. With no possibility of obtaining a same-species donor and because of the serious condition of the patient and unfavorable prognosis, a decision was made to perform the xenotransfusion. The result was a successful recovery and ultimately the release of the owl into its natural habitat. We concluded that xenotransfusion for avian species should be considered in cases with no possibility of obtaining a homologous donor.

Distraction Osteogenesis in Two Wild Raptors.

Distraction osteogenesis was used in 2 wild raptor patients for the repair of tibiotarsal fractures. The first case was a hatching year female peregrine falcon (Falco peregrinus) admitted with an open oblique right distal tibiotarsal fracture. The fracture was surgically managed with the external skeletal fixator intramedullary pin tie-in technique (ESF-IM pin tie-in). Appropriate healing of the fracture site occurred with the ESF-IM pin tie-in. However, there was significant pelvic limb shortening of the affected leg, and the bird consequently developed pododermatitis on the contralateral foot. The second case was an adult female great horned owl (Bubo virginianus) that was admitted with a closed, partially healed, overriding right tibiotarsal fracture. Because of the advanced stage of this fracture, which presented with a fibrous callus, and the already apparent pelvic limb shortening, the ESF-IM pin tie-in was not used. Both patients were fitted with a circular external skeletal fixator (CESF), and distraction osteogenesis was performed until the length of the pelvic limb was deemed anatomically adequate. It is critical that rehabilitated raptors be released without any physical conditions that may reduce their ability to survive and reproduce in the wild. Pelvic limb shortening can potentially predispose a raptor patient to pododermatitis, even with fatal consequences, in both captive and wild environments. The orthopedic technique used here proved useful to repair the limb shortening in both raptor cases, and each bird fully recovered and was released.

Case Series: Virulent hemosporidiosis infections in juvenile great horned owls (Bubo virginianus) from Louisiana and California, USA.

A total of eight juvenile great horned owls (Bubo virginianus) were found lethargic and on the ground in spring 2015, 2016, and 2017, including one fledgling from Louisiana, USA and seven nestlings from California, USA. One bird survived to release after rehabilitation; seven birds died or were euthanized due to poor prognosis and were necropsied. Necropsy findings were similar and included general pallor of all tissues, particularly the subcutis and lungs, and enlarged liver and spleen. Histopathology revealed multi-organ necrosis, abundant meronts containing merozoites, and intracytoplasmic pigmented haemosporidian parasites in blood cells in one bird. Leucocytozoon lineages lSTOCC16 and BUVIR06 were identified by polymerase chain reaction and genetic sequencing. The systemic Leucocytozoon infections were likely associated with morbidity and mortality in these owls. A second parasite, Haemoproteus lineage hSTVAR01, was also identified in an owl from Louisiana. This is the first identification of Leucocytozoon lineages that have been associated with mortality in young great horned owls.

Presumptive keratoglobus in a great horned owl (Bubo virginianus).

A juvenile to young adult, male, great horned owl (Bubo virginianus,GHOW) was presented to the wildlife rehabilitation hospital at Lindsay Wildlife Museum (WRHLWM) due to trauma to the right patagium from barbed wire entanglement. On presentation, both corneas were irregular, dry, and no movement of the third eyelid was noted. A severe corneal enlargement/globoid appearance was the predominant ophthalmic feature. The fundus was normal in both eyes (OU). Over the course of several days, both corneas developed edema combined with further dessication at the ocular surface associated with diffuse dorsal fluorescein stain uptake. Repeated ophthalmic examinations found normal intraocular pressures and an inability to move the third eyelid over the enlarged corneas. The bird was deemed nonreleasable due to severe wing damage and poor prognosis associated with eye abnormalities and was humanely euthanized. Postmortem CT, enucleation, and histopathology were performed to evaluate the ocular anatomical abnormality and confirm the suspected diagnosis of keratoglobus. This GHOW represents the first reported case of presumptive keratoglobus in a raptor.

Infecção por pox vírus e Aspergillus fumigatus em Bubo virginianus (Coruja jacurutu) / Avipoxvirus infecction in Bubo virginianus (great horned owl)

Este trabalho descreve um caso de infecção mista por pox vírus e Aspergillus fumigatus em Bubo virginianus (coruja jacurutu). A ave, um macho adulto, foi encaminhada ao Núcleo de Reabilitação da Fauna Silvestre do Instituto de Biologia da Universidade Federal de Pelotas (NURFS/CETAS/UFPEL). Apresentava bom estado corporal, estava ativa, porém com incapacidade de voo. Após três dias apresentou lesões crostosas e de aspecto verrucoso na superfície dorsal das patas. Havia, também, nódulos de mesmo aspecto na pálpebra esquerda e na cera. A ave morreu após 15 dias de sua chegada ao NURFS e foi necropsiada no Laboratório Regional de Diagnóstico da Faculdade de Veterinária da Universidade Federal de Pelotas (LRD/UFPel). Histologicamente, as lesões verrucosas caracterizavam-se por hiperplasia do epitélio e nas células das camadas basal, espinhosa, granular e córnea havia corpúsculos de inclusão intracitoplasmáticos do tipo Bollinger. Na microscopia eletrônica foram visualizadas partículas virais características de pox vírus, incluindo Bubo virginianus como um hospedeiro do vírus. Havia, ainda, infiltrado inflamatório de células mononucleares e focos de colônias bacterianas na derme. Nos pulmões havia congestão e presença de granulomas com hifas fúngicas, que pela técnica de Grocott, apresentaram ramificação dicotômica compatível com Aspergillus spp., identificado na cultura como A. fumigatus. O diagnóstico de infecção por avipoxvirus pode contribuir para estudos relacionados com a ocorrência desta doença nas populações de vida livre e como informação auxiliar para o manejo e conservação desta espécie. Sugere-se, ainda, a inclusão do uso de raios-X nos protocolos de centros de reabilitação como o diagnostico de aspergilose em aves rapinantes com bom estado corporal, porém incapazes de voar.(AU)

This paper describes a case of mixed infection by pox virus and Aspergillus fumigatus in Bubo virginianus (Owl Jacurutu). An adult male Bubo virginianus was referred to the Núcleo de Reabilitação da Fauna Silvestre, Instituto de Biologia, Universidade Federal de Pelotas (NURFS/CETAS/UFPEL). The owl was active and had a good body condition but with flight disability. After three days of their admission at NURFS the owl developed crusty and verrucous lesions at the dorsal surface of their feet. Also it had nodes on the left eyelid and cera with the same aspect. The owl died 15 days after its arrival. Necropsy and histopatological examination were carried out. The warty lesions had hyperplasia of the epithelium and intracytoplasmic Bollinger-like inclusion bodies in the basal, spinal, granulosa layer and cornea. Viral particles characteristic of pox viruses were shown by electron microscopy. This case includes Bubo virginianus as a host of the avipoxvirus. There were also a mononuclear inflammatory cell infiltrate and bacterial colonies in the dermis. In the lugs, there was congestion and presence of granulomas with intralesional fungal hyphae. With the Grocott stain those structures showed dichotomous branching which was later identified in mycological culture as characteristic for A. fumigates. The diagnosis of avipoxvirus infection can contribute to studies related to the occurrence of this disease in free-living populations and as auxiliary information for the management and conservation of this raptor species. It is also suggested to include the use of X-rays in rehabilitation center protocols as screening test to diagnose aspergillosis in birds of prey with good body condition but inability to fly.(AU)