Confirmed or suspected circoviral infection recently has been reported in several nonpsittacine birds. An overview of clinical signs of disease, gross lesions, and microscopic pathology of circoviral infections reported in nonpsittacine birds is presented. In addition, current methods of disease diagnosis, management, and prevention are discussed.

The relative sensitivity of conventional assays of liver function was evaluated in comparison with galactose clearance, a test of liver function used in humans since the 1960s. Results of galactose clearance tests were compared with plasma enzyme concentrations and serum bile acid levels in clinically normal galahs (Eolophus roseicapillus; n = 8), after celiotomy (n = 4), and after 6% or 18% hepatectomy (n = 8, respectively). Clearance tests and biochemical analyses were performed within 2–4 hours of surgery and at 4 and 7 days after surgery. Celiotomy and 6% and 18% hepatectomy resulted in changes in alkaline phosphatase, aspartate aminotransferase, and alanine aminotransferase concentrations that were consistent with muscle trauma. Celiotomy and 6% hepatectomy did not significantly alter the results of galactose clearance tests; however, 18% hepatectomy resulted in significant reduction in galactose clearance and galactose clearance as a function of body surface area (GEC-SA). Galactose single-point concentrations were not significantly elevated at any time during the experiments; however, single-point concentrations were strongly correlated with galactose clearance and GEC-SA values, especially at 80 minutes after galactose injection. Serum bile acid levels were not significantly elevated after celiotomy or partial hepatectomy. Measurement of galactose single-point concentrations has the potential to be a simple, sensitive method of screening for reduced hepatic function in birds. Galactose clearance and GEC-SA have the potential to be sensitive assays of hepatic functional mass, for use as a noninvasive method of monitoring hepatic function.

Serum corticosterone concentrations were evaluated in 40 adult Hispaniolan Amazon parrots (Amazona ventralis) after manual restraint and anesthesia and before and after skin testing. Twenty-four to 72 hours before the skin testing, blood samples were collected immediately after capture from manually restrained birds. On 2 separate days, half of the parrots in the study group (20 birds each) were anesthetized with isoflurane, and blood samples were taken immediately before and at 2.5, 7.5, and 17 minutes after skin testing. Serum samples were assayed by radioimmunoassay for corticosterone concentration. Although baseline corticosterone concentrations plotted against time varied in both anesthetized and manually restrained parrots, a downward trend was seen at 1400 hours (anesthetized birds) and at 1300 hours (manually restrained birds). The mean baseline concentration (±SEM) of corticosterone measured in birds that were manually restrained was significantly higher (33.7 ± 2.83 ng/ml) than that in anesthetized birds (19.8 ± 1.97 ng/ml). Mean corticosterone concentrations (±SEM) in anesthetized birds increased progressively after skin testing, from 19.8 ± 2.02 ng/ml before skin testing to 52.7 ± 2.63 ng/ml at 2.5 minutes, 63.1 ± 2.3 ng/ml at 7.5 minutes, and 74.5 ± 2.79 ng/ml at 17.0 minutes after skin testing. In birds, this increase in serum corticosterone concentration may account for the weak wheal formation observed during skin testing and emphasizes the need to read skin test results within a few minutes after intradermal injection.

Preprandial and postprandial plasma uric acid concentrations were evaluated in 12 healthy blackfooted penguins (Spheniscus demersus). Five male and 7 female penguins were fasted overnight, and blood was collected the next morning. Four days later, the same group of birds was given a morning feeding of fish ad libitum. Each bird's food consumption was recorded over a 2-hour feeding period. A blood sample was collected from each bird after removal of the fish (0- to 2-hour postprandial sample) and again 4 hours later (4- to 6-hour postprandial sample). Plasma samples were analyzed for uric acid and blood urea nitrogen (BUN) concentrations. In the 8 birds that consumed food during the 2-hour feeding period, plasma uric acid concentrations were significantly higher in both the 0- to 2-hour and 4- to 6-hour postprandial samples than in the preprandial samples. Uric acid concentrations were significantly lower in the 4- to 6-hour postprandial samples than in the 0- to 2-hour postprandial samples. Preprandial uric acid concentrations were <10 mg/dl, and 0- to 2-hour postprandial concentrations were >13.4 mg/dl (mean concentration = 21.2 mg/dl). No significant differences were found between preprandial and postprandial BUN concentrations. In penguins, uric acid concentrations must be measured after a fast to avoid a possible misdiagnosis of renal disease or gout.

Techniques for ultrasound imaging and percutaneous, ultrasound-guided fine-needle aspiration of the liver were initially tested on 5 Amazon parrots. The techniques were then applied to 27 clinically normal Amazon parrots. Each of the 27 birds was anesthetized with isoflurane and placed in dorsal recumbency with the head elevated 30°. Optimal imaging of the liver was achieved by cranially directing a 7.5-MHz pediatric mechanical sector transducer through a parasternal acoustic window. The normal sonographic appearance of the liver was evaluated. In each bird, an ultrasound-guided aspirate of the liver was collected by using a 22-gauge, 1-in needle connected to a 6-in extension set and a 3-ml syringe. Three techniques were used to collect the aspirates for cytologic evaluation, and the quality of the samples was compared microscopically. Samples with the lowest degree of hemodilution and the highest number and quality of hepatic cells were obtained by penetrating the liver parenchyma multiple times with the needle while simultaneously applying 0.5 ml of suction. Ultrasonographic examination of the liver 5 minutes after fine-needle aspiration revealed no hemorrhage in any bird. No morbidity or mortality occurred in any of the parrots during or after ultrasound imaging or ultrasound-guided fine-needle aspiration of the liver.

Mycotic keratitis is most commonly reported in horses and humans and is rarely reported in birds. We diagnosed mycotic keratitis, localized to the left eye, in an adult blue-fronted Amazon parrot (Amazona aestiva). The ophthalmic examination revealed a diffuse yellow-green haze encompassing the entire surface of the left cornea. Diffuse fluorescein uptake occurred in the entire cornea. The right eye appeared normal. Aspergillus fumigatus was isolated on conjunctival culture. The affected eye was enucleated because of the bird's discomfort and the poor prognosis for successful treatment. Histopathologic examination revealed a severe granulomatous keratitis with intracorneal fungal hyphae and corneal perforation. Multinucleated giant cells and fungal hyphae were present within the anterior chamber. Aspergillus fumigatus is an uncommon cause of keratitis in birds but should be considered as a potential cause of refractory ulcers.