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The use of procedural sedation in birds has become a routine practice in veterinary medicine during the past 10 years, with a corresponding increase in avian sedation research. Sedation is most often used in a clinical setting for birds to facilitate examination and/or diagnostic sample collection, splint application, grooming, and minor surgical procedures. Sedation provides several benefits over manual restraint or general anesthesia when performing clinical procedures. This review provides an overview of current studies on avian sedation and discusses common indications, protocols, and adverse effects of sedation in avian patients.
Alfaxalone is a safe and effective anesthetic drug for the induction of general anesthesia in many nonavian companion animal species; however, its efficacy has not been fully evaluated in birds. In premedicated trials, the chickens were sedated with butorphanol 2 mg/kg intramuscularly and midazolam 0.5 mg/kg intramuscularly, 15 minutes before intravenous administration of alfaxalone. The chickens were classified as anesthetized if endotracheal intubation was achieved without eliciting a cough reflex, provoking no patient resistance, and with minimal glottis movement within 15 seconds after the administration of alfaxalone. Qualitative and quantitative data were recorded, including duration of anesthesia, quality of induction, quality of recovery, reflexes, time to sternal recumbency, time to standing, and time to normal behaviors. Survival analysis was used to analyze the association between alfaxalone dosage and premedication with time-related variables. Out of the evaluated doses, the lowest intravenous alfaxalone dose required to achieve anesthetic induction and endotracheal intubation in unpremedicated and premedicated chickens was 7.5 and 4 mg/kg, respectively. The duration of anesthesia for all dose rates within the study ranged from 51 seconds to 4 minutes 45 seconds. Premedication generally improved the quality of induction and recovery, but significantly (P < .001) increased the time required for the chickens to stand after being anesthetized and to return to normal behaviors. Most chickens exhibited varying degrees of hyperactivity on anesthetic induction and recovery. No postinduction apnea or deaths of the subject birds occurred during this investigation.
New World vultures, such as turkey vultures (Cathartes aura), are obligate scavengers with large geographic ranges. In a preliminary characterization of the turkey vulture (TV) gastrointestinal microbiome in Southern California, we identified 2 recently described emerging bacterial pathogens not previously known to be associated with this avian species. High-throughput sequencing of broad-range 16S rRNA gene amplicons revealed sequences from TV cloacal swabs that were related closest to Wohlfahrtiimonas chitiniclastica and Ignatzschineria species, both Gammaproteobacteria considered by the United States Centers for Disease Control and Prevention as emerging zoonotic pathogens. None of these bacterial sequence types have been previously identified from samples obtained from the turkey vulture gastrointestinal microbiome. With the use of bioinformatics workflows previously established by our research group, we designed specific and sensitive polymerase chain reaction primer sets that represent novel diagnostic assays for the genera Wohlfahrtiimonas and Ignatzschineria. These primer sets were validated by Sanger sequence confirmation from complex TV samples. Because the genera Wohlfahrtiimonas and Ignatzschineria are both known to have dipteran hosts, the molecular diagnostic tools we present here should be useful for better understanding the role of flies, vultures, and other scavengers in the ecology and epidemiology of the genera Wohlfahrtiimonas and Ignatzschineria from a One Health perspective.
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.
Atherosclerosis is a chronic inflammatory disease that has been reported to affect the cardiovascular system of many avian species. However, atherosclerosis in raptor species has not been fully evaluated. The aim of this study was to histologically characterize central and peripheral atherosclerotic lesions in raptors that were submitted to a pathology service in Northern California from 1986 to 2013. We also evaluated risk factors, including age, gender, origin, and avian family. Atherosclerotic lesions were categorized as minimal, mild, moderate, or severe, based on the severity of the lesions and their distribution within the arterial wall. Among the central arteries, lesions were determined to be of greater severity in the aorta than in the pulmonary artery. More than 50% of the peripheral arteries were affected, including 53.1% (17/32) myocardial, 52% (13/25) coronary, 62.9% (22/35) arteries in the kidney, 52.2% (12/23) gonadal and 51.7% (15/29) splenic arteries; however, hepatic and pulmonary arteries were uncommonly affected. Atherosclerosis was diagnosed in 17 raptor species representing 4 families: Accipitridae, Cathartidae, Falconidae, and Strigidae. The overall prevalence (95% CI) of atherosclerosis in raptors was 2.3% (36/1574; range, 1.63%–3.19%) with the Falconidae having the highest prevalence at 7.4% (9/122; range 3.64%–13.93%) and with 0% detected in the Tytonidae and Pandionidae families. A multiple logistic regression model that jointly accounted for differences in risk by family, age, and gender found that the risk in Accipitridae was significantly less than that of Falconidae, that adult raptors were at greater risk of atherosclerotic lesions than juveniles were, and that females were more frequently affected than males were.
Although serum protein electrophoresis is a diagnostic tool available through many veterinary laboratories, there currently are no reference intervals for protein fractions in healthy common mynahs (Acridotheres tristis). Therefore, electrophoretic patterns of proteins in serum and heparinized plasma of the common mynah were evaluated. Blood specimens were collected from 55 healthy adult common mynahs of unknown age (26 males and 29 females). The serum total protein and protein fractions were measured using the biuret method followed by cellulose acetate electrophoresis (CAE). The serum level of albumin was compared with bromocresol green (BCG) dye-binding and CAE methods. Four protein fractions, including albumin and α, β, and γ globulins, were recorded in the electrophoretogram of serum specimens. Sex appeared to have no significant effect on the measured parameters. The serum BCG albumin fraction was significantly higher than the CAE albumin fraction (P = .01). Also, the comparison of total protein and protein fractions in serum and plasma specimens of 25 of the 55 birds sampled showed that total protein (Cohen index d = 0.66, P = .03), gamma globulin (d = 1.13, P = .00), and total globulin (d = 0.67, P = .00) in plasma samples were significantly higher than those in serum samples. The results of this study provide the specific reference intervals for total protein and protein fractions in common mynahs, which are essential for proper interpretation of laboratory results and also revealed that the albumin measurement by the BCG method yields unreliable results in common mynahs.
Birds are among the most visually proficient group of animals on the planet; however, their inability to visualize and discriminate translucent glass structures results in an extreme number of deaths worldwide from high-speed collisions. Despite reports of avian glass collisions in North America, only a few studies have been developed to understand this problem in South America, and none evaluated radiographic and postmortem findings. One hundred cadavers were examined radiographically and postmortem, and data from 186 collision reports were analyzed for seasonality (website and manual reports and cadavers). A total of 34 different species of birds within 22 families were evaluated for this study, with the rufous-bellied thrush (Turdus rufiventris; n = 12), eared dove (Zenaida auriculata; n = 12), and ruddy ground dove (Columbina talpacoti; n = 10) being the most common species. Only 6 (27.7%) migratory species were reported: Sick's swift (Chaetura meridionalis), small-billed elaenia (Elaenia parvirostris), Black Jacobin (Florisuga fusca), Great kiskadee (Pitangus sulphuratus), Double-collared seedeater (Sporophila caerulescens), and Creamy-bellied thrush (Turdus amaurochalinus). Males (51) were more frequently reported than females (5), and 50.1% of the males had active gonads. Sex was unable to be determined in 44 birds. The most common radiographic lesion, noted in 16 of 82 (19.5%) animals, was loss of coelomic definition, suggestive of hemorrhage. Prevalent postmortem findings included skull hemorrhages (58/75, 77.3%) and encephalic contusions (47/73, 64.4%), followed by coelomic hemorrhages (33/81, 40.7%). Most of the window collisions (61/186, 32.8%) occurred during spring, the most common breeding season of avian species in Brazil. Cranioencephalic trauma was identified as the primary cause of mortality associated with birds flying into glass windows. Migration does not appear to be the main predisposing factor for window collisions by birds in Brazil. Increased activity and aggression related to breeding season, especially in males, may be a more important predisposing factor for window collision accidents.
Beak and feather disease virus (BFDV), a circovirus, is the etiologic agent of psittacine beak and feather disease (PBFD), a progressive and often fatal disease in Psittaciformes. Even though neotropical psittacine species are more resistant to clinical infection than Old World species, BFDV is recognized as a threat to immunologically naïve wild psittacine flocks and its epidemiologic control is paramount for conservation efforts in Neotropical species. Samples were collected from multiple psittacine species, including Ara species, Amazona species, and the white-crowned parrot (Pionus senilis) from the only rescue center in Guatemala with formal psittacine rehabilitation and reintroduction programs. A total of 117 birds, with 101 adults and 16 juveniles of unknown sex, were tested for BFDV by means of a real-time polymerase chain reaction (PCR) assay. The BFDV prevalence found in this study was 0%, (95% confidence interval, 0%–6.0%). Seven 2–8-year-old scarlet macaws (Ara macao cyanoptera) with positive results from previous surveys by conventional PCR yielded negative results in this study, suggesting complete infection resolution.
Chlamydiaceae are obligate intracellular bacteria with a broad host range. Several studies have found chlamydial species that are genetically intermediate between Chlamydia psittaci and Chlamydia abortus in various avian species. One of these intermediate Chlamydia species, found in a red-shouldered hawk (Buteo lineatus), was recently classified as a new species Chlamydia buteonis. This newly described Chlamydia species has, so far, only been reported in hawks exhibiting clinical signs of conjunctivitis, dyspnea, and diarrhea. In the present study, fecal samples of 5 gyrfalcons (Falco rusticolus), 3 gyr/peregrine falcon hybrids (Falco rusticolus × Falco peregrinus), and 15 falcons of unknown species presented to falcon clinics on the Arabian Peninsula were shipped to the Vetsuisse Faculty, University of Zurich (Zurich, Switzerland), for examination for the presence of Chlamydiaceae. A step-wise diagnostic approach was performed to identify the chlamydial species involved. Chlamydiaceae were detected in 21/23 falcons by a family-specific real-time quantitative PCR (qPCR). Further identification with a 23S ribosomal RNA-based microarray assay and 16S conventional PCR and sequencing yielded inconclusive results, indicating the presence of an intermediate Chlamydia species. Because none of the falcons tested positive for Chlamydia psittaci by specific qPCR, all 23 samples were subjected to a Chlamydia buteonis–specific qPCR, which was positive in 16/23 samples. Detailed information regarding clinical history was available for 8 falcons admitted to a falcon clinic in Dubai, United Arab Emirates. Six of those birds that were presented to the clinic because of loss of performance and poor general condition, including vomiting and diarrhea, were positive for C buteonis. In 2 birds without clinical disease signs admitted for a routine health examination, 1 was positive for C buteonis, and 1 was negative. It is yet unknown whether Chlamydia buteonis causes disease in birds, but the findings in this study indicate that Chlamydia buteonis may be an infectious pathogen in falcon species.
A 24-year-old, female cockatiel (Nymphicus hollandicus) was diagnosed and treated for chronic lymphocytic leukemia. Diagnosis was based on a persistent lymphocytosis, with counts increasing 10 times from reference intervals with a high percentage of well-differentiated lymphocytes in the bone marrow. Immunohistochemical staining confirmed neoplastic cells of T-cell origin. Specific treatment for the disease was initially withheld but commenced based on an increasing lymphocytosis and decreasing packed cell volume. Therapeutic management of the cockatiel's chronic lymphocytic leukemia was based on human protocols. Treatment with chlorambucil stabilized the disease but did not result in a significant regression of the neoplasm. The bird was euthanatized 15 months after the initial diagnosis and 8 months after treatment commenced. On the postmortem examination, extensive T-cell lymphocytic infiltration was found throughout the internal organs.
Whereas craniodorsal displacement of the coxofemoral joint is the most common luxation reported in small and large mammals, it occurs less often in avian species. Closed reduction and external coaptation with a modified Ehmer sling is the initial treatment, in most cases, for small animals (eg, dogs, cats) that present with a coxofemoral luxation. However, the Ehmer sling is reported to have a low success rate in treating coxofemoral luxations in these animals. Intractable coxofemoral luxations require an open surgical reduction. A few successful closed reductions of coxofemoral luxations have been reported in avian patients, as well as open reduction surgical techniques to repair avian coxofemoral luxations. The successful treatment of an acute craniodorsal coxofemoral luxation in a scarlet ibis (Eudocimus ruber) with a closed reduction and a modified Ehmer sling is described in this clinical report. The specific characteristics of both the patient and the injury are thought to have contributed to the success in this case.
An Indian runner duck (Anas platyrhynchos domesticus) was presented for a second opinion after a linear, metallic foreign body was identified on radiographic images. The primary veterinarian performed diagnostic imaging while investigating the presenting complaint of the duck's left pelvic limb lameness. The images obtained from a computed tomography scan performed during the second-opinion visit revealed a linear, metallic foreign body with an associated migration tract originating from the ventriculus and terminating in the proximal left femur. Significant osteomyelitis was noted at the proximal left femur associated with the presence of the linear, metallic object. The foreign body and the adhesions associated with its migration were removed in 2, staged, surgical procedures. Although penetrating ventricular foreign bodies have been previously reported, migration through the cortex of a long bone is an unusual presentation. This case demonstrates that perforating, migrating, gastrointestinal foreign bodies can result in lameness refractory to analgesia and ancillary supportive care.
KEYWORDS: ocular neoplasia, uveal melanoma, ophthalmology, psittacine, hybrid macaw, calico macaw, Avian, green-winged macaw, Ara chloropterus, military macaw, Ara militaris
An adult male green-winged (Ara chloropterus) × military (Ara militaris) hybrid macaw of unknown age was presented to the Texas A&M Veterinary Medical Teaching Hospital for evaluation of left periocular swelling, blepharospasm, and ocular discharge. Complete ophthalmic examination and B mode ocular ultrasonography were performed to evaluate the affected eye. Ocular examination revealed a blind left globe with exophthalmos, periocular swelling, diffuse corneal edema, and severe anterior fibrinous uveitis obscuring visualization of the intraocular structures. An ultrasound examination revealed a hyperechoic mass that filled the posterior segment of the globe. Focal discontinuity of the posterior sclera suggested scleral rupture. Enucleation with histopathology was recommended and performed 1.5 months later. Intraoperatively, a heavily pigmented and friable soft tissue mass extruded through the posterior sclera and extended into the orbit. Histologically, the mass was consistent with a malignant melanoma. The patient died 18 hours after the surgical procedure because of unknown complications. Postmortem examination did not identify evidence of metastasis. This study described the clinical appearance and histopathologic findings of a rare ocular neoplasm with extrascleral extension in a hybrid macaw. Although uncommon in psittacine birds, primary ocular melanocytic neoplasms may display features of malignancy with scleral or orbital invasion, or both.
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