Surveillance for highly pathogenic avian influenza A (H5N1) in a raptor rehabilitation center-2022.

An ongoing, severe outbreak of highly pathogenic avian influenza virus (HPAI) A H5N1 clade 2.3.4.4b has been circulating in wild and domestic bird populations throughout the world, reaching North America in 2021. This HPAI outbreak has exhibited unique characteristics when compared to previous outbreaks. The global distribution of disease, prolonged duration, extensive number of species and individual wild birds affected, and the large impact on the global poultry industry have all exceeded historical impacts of previous outbreaks in North America. In this study, we describe the results of HPAI surveillance conducted at The Raptor Center, a wildlife rehabilitation hospital at University of Minnesota (Saint Paul, MN, U.S.A.), from March 28th-December 31, 2022. All wild raptors admitted to the facility were tested for avian influenza viruses using polymerase chain reaction (PCR) testing. All non-negative samples were submitted to the United States Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS) National Veterinary Services Laboratories for confirmatory HPAI testing and genetic sequencing. During the study period, 996 individual birds representing 20 different species were tested for avian influenza, and 213 birds were confirmed HPAI positive. Highly pathogenic avian influenza surveillance conducted at The Raptor Center contributed 75% of the HPAI positive raptor detections within the state of Minnesota, located within the Mississippi flyway, significantly augmenting state wildlife surveillance efforts. The viral genotypes observed in birds sampled at The Raptor Center were representative of what was seen in wild bird surveillance within the Mississippi flyway during the same time frame. Wildlife rehabilitation centers provide an opportune situation to augment disease surveillance at the human, wildlife and domestic animal interface during ongoing infectious disease outbreaks.

Lesions and viral antigen distribution in bald eagles, red-tailed hawks, and great horned owls naturally infected with H5N1 clade 2.3.4.4b highly pathogenic avian influenza virus.

An epidemic of highly pathogenic avian influenza (HPAI) began in North America in the winter of 2021. The introduced Eurasian H5N1 clade 2.3.4.4b virus subsequently reassorted with North American avian influenza strains. This postmortem study describes the lesions and influenza A virus antigen distribution in 3 species of raptors, including bald eagles (Haliaeetus leucocephalus, n = 6), red-tailed hawks (Buteo jamaicensis, n = 9), and great horned owls (Bubo virginianus, n = 8), naturally infected with this virus strain based on positive reverse transcriptase polymerase chain reaction and sequencing results from oropharyngeal swabs. The birds presented with severe neurologic signs and either died or were euthanized because of the severity of their clinical signs and suspected influenza virus infection. Gross lesions were uncommon and included forebrain hemorrhages in 2 eagles, myocarditis in 1 hawk, and multifocal pancreatic necrosis in 3 owls. Histological lesions were common and included encephalitis, myocarditis, multifocal pancreas necrosis, multifocal adrenal necrosis, histiocytic splenitis, and anterior uveitis in decreasing frequency. Influenza A viral antigen was detected in brain, heart, pancreas, adrenal gland, kidney, spleen, liver, and eye. In conclusion, bald eagles, red-tailed hawks, and great horned owls infected with the HPAI clade 2.3.4.4b virus strain and showing neurological signs of illness may develop severe or fatal disease with histologically detectable lesions in the brain that are frequently positive for viral antigen.

An avian Modified Glasgow Coma Scale as a prognostic indicator in raptors with head trauma.

OBJECTIVE: To develop a Modified Glasgow Coma Scale (MGCS) for use in raptors presenting with head trauma and assess the agreement of the MGCS scores between examiners with varying backgrounds, and to assess the prognostic value of the avian MGCS in raptors with head trauma. ANIMALS: 156 native raptorial species. METHODS: All raptors received an MGCS assessment within 8 hours of their presentation, between January 1, 2018, and December 31, 2019. For the first objective, the assessment was performed by a veterinary student, a wildlife veterinarian, and a board-certified or resident veterinary neurologist. Each animal received a score in 3 categories (motor activity, level of consciousness, and brain stem reflexes) and an overall score. For the second objective, the MGCS scoring was performed by the intaking clinical team member and survival after 48 hours was documented. RESULTS: Agreement between the 3 individual scores was assessed via Cronbach α and intraclass correlation. There was excellent-good agreement in all 3 assessment categories as well as the overall score. Univariate associations between survival and demographic factors were determined using the χ2 test. Overall, raptors with a total MGCS of < 10 were less likely to survive than those with a score > 12. CLINICAL RELEVANCE: An avian-specific MGCS demonstrated good-excellent agreement among raters of various backgrounds in assessing raptors with head trauma. Additionally, this study showed that an avian-specific MGCS may be correlated with the probability of survival within the first 48 hours after presentation to rehabilitation facilities in raptors with head trauma.

Massive hepatic trematodosis in 5 juvenile bald eagles.

Hepatic trematodosis by opisthorchiid flukes has been reported sporadically in North American fish-eating raptors. Bald eagles (Haliaeetus leucocephalus) infected by these flukes often have various degrees of granulomatous cholangitis, pericholangitis, necrosis of adjacent hepatocytes, and subsequent hepatic fibrosis. Species identification has been complicated by the inability to dissect intact specimens from liver tissue. Between 2007 and 2018, 5 juvenile bald eagles with massive hepatic trematodosis were identified at autopsy. Histologically, flukes were non-spinous. Parasitologic identification revealed ventral suckers (80-93 µm diameter), and uteri containing golden, operculated eggs (~25.0 × 12.0 µm). An unfixed frozen liver sample of one eagle was analyzed by PCR and DNA sequencing targeting the large subunit rRNA, ITS region, and cox1 genes of the parasite. The fluke DNA sequences shared 99.6%, 98.4%, and 87.0% similarity, respectively, with Erschoviorchis anuiensis, a newly described opisthorchiid species infecting the liver and pancreas of fish-eating birds in Europe and Asia. Infection by E. anuiensis is highly pathogenic in several piscivorous bird species. The clinical significance of trematodosis in our 5 cases is uncertain because all birds had comorbidities.

Assessment of 2 Treatment Methods for Ulna Fractures With an Intact Radius in Raptors: Conservative Management and Surgical Fixation With a Type I External Skeletal Fixator Intramedullary Pin Tie-in.

Several methods have been reported for treating avian antebrachial fractures, yet the quantitative information regarding their success is limited. This retrospective study applied data from raptors admitted to a wildlife rehabilitation center to provide metrics associated with the treatment of ulna fractures with an intact radius by either conservative management or a single surgical method: a type I external skeletal fixator tied in to an intramedullary pin (ESF IMP tie-in). Postfledging wild raptors with an ulna fracture admitted to The Raptor Center at the University of Minnesota College of Veterinary Medicine (St Paul, MN, USA) between January 1, 2007, and December 31, 2017, that survived for at least 7 days after admission were included in the study. Information regarding signalment, fracture characteristics, treatment method, outcome, and complications were recorded. The study included 110 raptors representing 15 species. The majority of birds (69%, 76/110) were treated with conservative management. Conservative management was used more often in cases of chronic (P = .02) and closed (P = .02) fractures, whereas fractures with poor alignment at the time of admission were frequently treated through surgical means (P=.001). Alignment was more likely to improve with an ESF IMP tie-in (P=1.01 ×10-9). The majority of cases (65%, 72/110) had a successful outcome. Birds with closed fractures were more likely to have a successful outcome (P=.03). Birds in which fracture alignment became exacerbated with either treatment method were more likely to have a poor outcome (P=.002). The results of this retrospective study found that conservative management and surgical fixation by the ESF IMP tie-in technique are both viable treatment options for ulna fractures with an intact radius in raptors. The choice of treatment method is dependent on the clinician's assessment of the fracture characteristics and individual patient.

Evaluation of neurobehavioral abnormalities and immunotoxicity in response to oral imidacloprid exposure in domestic chickens (Gallus gallus domesticus).

Domestic chickens (Gallus gallus domesticus) were exposed to imidacloprid by gavage once daily for 7 consecutive days at 0, 0.03, 0.34, 3.42, 10.25, and 15.5 mg/kg/day (n = 20 per group; 5 6-week-old males, 5 6-week-old females, 5 9-week-old males, and 5 9-week-old females). The severity and duration of neurobehavioral abnormalities were recorded. Components of the innate and adaptive immune system were assessed with 7 standard functional assays. Temporary neurobehavioral abnormalities were observed in a dose-dependent manner, including muscle tremors, ataxia, and depressed mentation. Based upon mean clinical severity scores, the no observed adverse effect level (NOAEL) was 3.42 mg/kg/day, and the lowest observed adverse effect level (LOAEL) was 10.25 mg/kg/day. The effective dose value for the presence of any neurobehavioral abnormalities in 50% of the test group (ED50) was 4.62 ± 0.98 mg/kg/day. The ED50 for an adjusted score that included both severity and duration of neurobehavioral abnormalities was 11.24 ± 9.33 mg/kg/day. These ED50 values are equivalent to a 1 kg bird ingesting 29 or 70 imidacloprid treated soybean seeds respectively. Immunotoxicity was not documented, possible causes include the assays were insensitive, relevant immune functions were not examined, or imidacloprid is not immunotoxic at this dosing schedule in this species. Neurobehavioral abnormalities were a more sensitive indicator of the sublethal effects of imidacloprid than immunotoxicity.

PREVALENCE OF BOX TURTLE ADENOVIRUS IN EASTERN BOX TURTLES (TERRAPENE CAROLINA CAROLINA) PRESENTED TO A WILDLIFE REHABILITATION CENTER IN VIRGINIA, USA.

Eastern box turtles (Terrapene carolina carolina) are a native North American species with a declining population trend that may be attributable to habitat fragmentation, vehicle collisions, and disease. Adenoviral infections can cause significant morbidity and mortality in captive reptile populations. Adenoviruses have been documented in box turtles, but their occurrence and impact in wild populations are unknown. A disease survey was performed at The Wildlife Center of Virginia, USA, to assess the prevalence of box turtle adenovirus (BTAdV) in wild eastern box turtles and evaluate potential associations with clinical disease. Swabs from the oral cavity, including the choanal slit, and the cloaca were collected from 106 eastern box turtles from July 2015 through June 2016. The quantitative polymerase chain reaction (qPCR) primer detected both ornate box turtle adenovirus 1 and eastern box turtle adenovirus. The resulting qPCR adenovirus prevalence was 55.7% (n = 59). Most animals (99.3%) that tested positive for BTAdV had fewer than 100 viral copies/ng DNA. This study did not find a statistically significant association between cause of admission, age, sex, outcome, and BTAdV qPCR status. However, the probability of BTAdV detection was 1.5 times higher in rehabilitation turtles compared with wild turtles (P = 0.01). Albumin was significantly lower in qPCR BTAdV-positive turtles (P = 0.007). Hypoalbuminemia is not generally associated with adenovirus infections in other species, and no obvious clinical cause for this abnormality was identified. The results of this study suggest that eastern box turtles may harbor BTAdV infections at low levels and that infection is rarely associated with clinical disease, potentially identifying BTAdV as a host-adapted pathogen. Future studies should focus on this pathogen's ability to induce clinical disease and its potential impact on recovery efforts for this species.

Bilateral Anterior Uveitis in a Northern Saw-whet Owl (Aegolius acadicus) With a Metastatic Pectoral Malignant Mesenchymoma.

A captive, adult, male northern saw-whet owl (Aegolius acadicus) was examined for blepharospasm of the left eye. The owl was diagnosed with bilateral anterior uveitis and a corneal ulceration in the left eye. It was treated with oral and topical nonsteroidal anti-inflammatory medications and a topical antibiotic. Multiple recheck examinations and medication adjustments were performed over the next 4 months, at the end of which time the bilateral anterior uveitis was controlled with a topical nonsteroidal anti-inflammatory applied 3 times per week to both eyes. The owl was re-examined 2 months later after 2 suspected neurologic episodes. On physical examination, the owl was quiet and had difficulty standing and ambulating. Five firm multilobular and immobile masses were identified overlying the pectoral muscle and sternum. Fine-needle aspiration from 1 mass revealed neoplastic cells consistent with a sarcoma. The owl was euthanatized. On the basis of results of histopathologic examination, the mass was diagnosed as a pleomorphic spindle cell sarcoma with features of rhabdomyosarcoma, liposarcoma, and osteosarcoma. Numerous tumor cells were immunopositive for myoglobin and desmin, indicating striated muscle origin. Although a metastatic lesion was present in 1 adrenal gland, lesions of inflammation or neoplasia were absent in either eye on histopathologic examination. This report describes an apparent ocular manifestation of systemic disease in an avian species with clinically diagnosed recurrent anterior uveitis.

The Use of Lead Isotope Analysis to Identify Potential Sources of Lead Toxicosis in a Juvenile Bald Eagle ( Haliaeetus leucocephalus) With Ventricular Foreign Bodies.

A male juvenile bald eagle ( Haliaeetus leucocephalus) was admitted to the Wildlife Center of Virginia with a left humeral fracture a large quantity of anthropogenic debris in the ventriculus, a blood lead level of 0.616 ppm, and clinical signs consistent with chronic lead toxicosis. Because of the poor prognosis for recovery and release, the eagle was euthanatized. Lead isotope analysis was performed to identify potential anthropogenic sources of lead in this bird. The lead isotope ratios in the eagle's femur (0.8773), liver (0.8761), and kidneys (0.8686) were most closely related to lead paint (0.8925), leaded gasoline (0.8450), and zinc smelting (0.8240). The lead isotope ratios were dissimilar to lead ammunition (0.8179) and the anthropogenic debris in the ventriculus. This case report documents foreign body ingestion in a free-ranging bald eagle and demonstrates the clinical utility of lead isotope analysis to potentially identify or exclude anthropogenic sources of lead poisoning in wildlife patients.

PHARMACOKINETICS OF PIROXICAM IN CRANES (FAMILY GRUIDAE).

To investigate the pharmacokinetics of the nonsteroidal anti-inflammatory drug (NSAID) piroxicam in cranes, three brolgas (Antigone rubicunda) were administered piroxicam as a single oral dose at 0.5 mg/kg and 1.0 mg/kg during separate trials. Serial blood samples were collected for quantification of piroxicam in plasma. Piroxicam was readily absorbed at both dosages, and no adverse effects were observed. Plasma concentrations peaked at 3.67 hr with a concentration of 4.00 µg/ml for the lower dosage, and at 0.83 hr at 8.77 µg/ml for the higher dosage. Piroxicam may exhibit linear kinetics and dose proportionality in brolgas, but will require further study. Mean peak plasma concentrations in brolgas were comparable to concentrations demonstrated to be analgesic in humans. To the authors' knowledge, this study represents the first pharmacokinetic investigation of piroxicam in an avian species.