Probable Enalapril Hepatotoxicity in a 13-Year-Old Male Western Lowland Gorilla: Pharmacologic Risks and Vigilance.

A 13-year-old male Western lowland gorilla presented acutely with a precipitous decline in health status from liver disease. Through diagnostic assessment, including serum chemistries and advanced imaging, it was diagnosed with probable hepatotoxicity resulting from its prescribed medication, enalapril. As one of several angiotensin converting enzyme inhibitors (ACE-I) available to zoo veterinarians, enalapril had been administered for treatment of mild ventricular hypertrophy diagnosed during routine examination 2.5 years prior to the presentation. The gorilla made a complete recovery with discontinuation of this medication, and provision of hepatoprotectants. Hepatotoxicity has been documented in humans receiving this product as an adverse drug reaction and is considered both rare and unpredictable in occurrence. In this event, an association was suspected with indulgent consumption of mulberry browse (Morus sp.) offered as nutritional enrichment immediately prior to clinical presentation and had potential impact on hepatic cytochrome P450 metabolism of the enalapril. Although ACE-I are important medications in this taxon due to its predisposition to cardiac disease, this event underscores the need for vigilance on the part of veterinarians and managers whenever pharmaceuticals are administered. Most drugs are modeled in a limited number of species but utilized in a wide variety, and unintended results are possible.

LONG-TERM SURVEILLANCE OF LANGUR ALPHAHERPESVIRUS IN A ZOO POPULATION OF SILVERED LANGURS ( TRACHYPITHECUS CRISTATUS).

Langur alphaherpesvirus (HVL), a provisionally named alphaherpesvirus in the Simplexvirus genus, was first identified in 1991 at the Bronx Zoo in wild-origin silvered langurs ( Trachypithecus cristatus) and their descendants. HVL is closely related to B virus ( Macacine alphaherpesvirus 1) based on serologic and genetic data, but its natural history and zoonotic potential remain unknown. A cohort study was undertaken to describe the epidemiology, clinical impact, and potential management implications of this virus in a naturally infected, zoo-based population of silvered langurs. Opportunistic surveillance sampling from 1991 through 2015 resulted in 235 serum samples and 225 mucosal swabs from 75 individuals. A total of 43 individuals (57.3%) were seropositive for HVL within this period. Seroprevalence increased significantly with age, and indirect evidence suggested a peak in transmission at the onset of sexual maturity. These findings were similar to the behavior of other simplexviruses in their adapted hosts. Yearly cumulative incidence declined significantly through the study period, with zero or one new case detected each year from 2007 through 2015. The density of this population decreased within the study period for management reasons unrelated to HVL infection, and a change in age distribution or less-frequent contacts may have contributed to low transmission. In addition, clinical signs of simplexvirus infection were rare, and virus isolation was negative on all mucosal swabs, suggesting that viral shedding was infrequent. Yearly period seroprevalence remained relatively constant with a median of 45.8%, likely because of the extended survival of infected individuals within the population. Maintenance of a naturally occurring, novel virus with unknown zoonotic potential in a zoo population for over 25 yr highlights the importance of biosecurity and biosafety for management of silvered langurs and all primate species.

Ocular anatomy of the black pacu (Colossoma macropomum): gross, histologic, and diagnostic imaging.

OBJECTIVE: To describe the ocular anatomy of the black pacu (Colossoma macropomum), a freshwater teleost fish of the Amazon River basin, including an unusual choroid laden with adipose tissue. PROCEDURES: Three adult black pacu were anesthetized and examined clinically and with ocular ultrasonography, then euthanized. Three fish were euthanized and their heads imaged immediately postmortem using computed tomography. One fish was euthanized and its exenterated eyes imaged by high-resolution magnetic resonance imaging. The exenterated eyes of all seven fish were fixed in formalin; eyes from three fish were examined grossly and histologically. Additionally, archived histologic sections from two smaller black pacu specimens were examined. RESULTS: Findings were consistent among the ocular imaging modalities used. Intrinsic to the sclera were circumferential ossicles and scleral cartilage. The lens was spherical and protruded through the ovoid pupil with an aphakic space inferiorly when the accommodative mechanism was relaxed under anesthesia. Both a small falciform process and epiretinal vasculature were present in the posterior segment. The retina was cone-rich, and processes of the retinal pigment epithelium enveloped the photoreceptor outer segments. Remarkably, the choroid occupied one-third of the anteroposterior length of the globe; histology confirmed that the bulk of the choroid was composed of adipose tissue. CONCLUSIONS: The eye of the pacu overall is typical of teleosts but has the notable and consistent finding of a substantive store of choroidal fat of unknown function.

Comparison of intraosseous pentobarbital administration and thoracic compression for euthanasia of anesthetized sparrows (Passer domesticus) and starlings (Sturnus vulgaris).

OBJECTIVE To compare intraosseous pentobarbital treatment (IPT) and thoracic compression (TC) on time to circulatory arrest and an isoelectric electroencephalogram (EEG) in anesthetized passerine birds. ANIMALS 30 wild-caught adult birds (17 house sparrows [Passer domesticus] and 13 European starlings [Sturnus vulgaris]). PROCEDURES Birds were assigned to receive IPT or TC (n = 6/species/group). Birds were anesthetized, and carotid arterial pulses were monitored by Doppler methodology. Five subdermal braided-wire electrodes were used for EEG. Anesthetic depth was adjusted until a continuous EEG pattern was maintained, then euthanasia was performed. Times from initiation of euthanasia to cessation of carotid pulse and irreversible isoelectric EEG (indicators of death) were measured. Data (medians and first to third quartiles) were summarized and compared between groups within species. Necropsies were performed for all birds included in experiments and for another 6 birds euthanized under anesthesia by TC (4 sparrows and 1 starling) or IPT (1 sparrow). RESULTS Median time to isoelectric EEG did not differ significantly between treatment groups for sparrows (19.0 and 6.0 seconds for TC and IPT, respectively) or starlings (88.5 and 77.5 seconds for TC and IPT, respectively). Median times to cessation of pulse were significantly shorter for TC than for IPT in sparrows (0.0 vs 18.5 seconds) and starlings (9.5 vs 151.0 seconds). On necropsy, most (14/17) birds that underwent TC had grossly visible coelomic, pericardial, or perihepatic hemorrhage. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that TC might be an efficient euthanasia method for small birds. Digital pressure directly over the heart during TC obstructed venous return, causing rapid circulatory arrest, with rupture of the atria or vena cava in several birds. The authors propose that cardiac compression is a more accurate description than TC for this procedure.

EFFECTS OF EXERCISE ON THE PLASMA LIPID PROFILE IN HISPANIOLAN AMAZON PARROTS (AMAZONA VENTRALIS) WITH NATURALLY OCCURRING HYPERCHOLESTEROLEMIA.

Hypercholesterolemia is common in psittacines, and Amazon parrots ( Amazona spp.) are particularly susceptible. Associations have been demonstrated between naturally occurring and experimentally induced hypercholesterolemia and atherosclerosis in psittacines. Daily exercise improves lipid metabolism in humans and other mammals, as well as pigeons and chickens, under varying experimental conditions. Hispaniolan Amazon parrots ( Amazona ventralis ) with naturally occurring hypercholesterolemia (343-576 mg/dl) were divided into two groups. An exercised group (n = 8) was housed as a flock and exercised daily with 30 min of aviary flight and 30 min walking on a rotating perch. A sedentary control group (n = 4) was housed in individual cages with no exercise regime. A plasma lipid panel, including total cholesterol, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol, and triglycerides, was validated for this species. Body weight, chest girth, and the lipid panel were measured at 0, 61, and 105 days. Hematology and plasma biochemistry were measured at 0 and 105 days. Weight and girth were significantly lower in exercised than sedentary parrots at 61 and 105 days. HDL-C concentrations were significantly higher in exercised parrots at 61 days but returned to near baseline by 105 days. There were no significant changes in hematology, biochemistry, or other lipid panel parameters. Results were similar to studies in humans and animal models, in which increased HDL-C was the most consistent effect of exercise on circulating lipid and lipoprotein parameters. The return toward baseline HDL-C may have resulted from decreased participation in aviary flight. Additional investigation will be required to determine the amount of exercise and change in circulating lipid-related parameters necessary to improve long-term wellness in psittacine species predisposed to hypercholesterolemia.

Evaluation of the mydriatic effects of topical administration of rocuronium bromide in Hispaniolan Amazon parrots (Amazona ventralis).

UNLABELLED: OBJECTIVE :To determine the mydriatic effects of topical rocuronium bromide administration in Hispaniolan Amazon parrots (Amazona ventralis) and to identify any adverse effects associated with treatment. DESIGN: Randomized crossover study. ANIMALS: 8 healthy adult Hispaniolan Amazon parrots. PROCEDURES: Rocuronium bromide (20 µL/eye; 10 mg/mL) or saline (20 µL/eye; 0.9% NaCl) solution was administered in both eyes of each bird with a 26-day washout period. The birds were manually restrained in lateral recumbency with the apex of the cornea positioned upward for 2 minutes following administration in each eye. Infrared pupillometry and direct pupillary light reflex measurements were used to evaluate the mydriatic effects. Pupillary measurements were recorded prior to administration and every 20 minutes for 2 hours after administration, then hourly for a total of 7 hours. A brief physical examination was performed, direct pupillary light reflex was tested, and fluorescein staining was performed on each eye of each bird 24 hours after administration. RESULTS: A significant difference in pupillary diameter for the active versus control treatment group was noted from 20 to 360 minutes after drug administration, but not at 420 minutes. Minimal adverse effects were noted. Three birds had transient inferior eyelid paresis noted in both eyes after receiving rocuronium; 24 hours after the treatment, no differences in ocular measurements existed between the active and control treatments. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that topical rocuronium bromide administration may be safely used for pupillary dilation in Hispaniolan Amazon parrots and could be used for clinical evaluation, fundus imaging, and surgical interventions involving the lens and posterior segment in this species.

Renal, gastrointestinal, and hemostatic effects of oral administration of meloxicam to Hispaniolan Amazon parrots (Amazona ventralis).

OBJECTIVE: To investigate renal, gastrointestinal, and hemostatic effects associated with oral administration of multiple doses of meloxicam to healthy Hispaniolan Amazon parrots (Amazona ventralis). ANIMALS: 12 Hispaniolan Amazon parrots. PROCEDURES: Birds were assigned to receive meloxicam oral suspension (1.6 mg/kg, PO, q 12 h) and 2.5 mL of tap water inserted into the crop by use of a gavage tube (n = 8) or the equivalent volume of tap water only (control group; 4) for 15 days. Urine and feces were collected 2 hours after treatment administration each day. Feces were evaluated for occult blood. Results of a CBC and serum biochemical analysis and measured N-acetyl-ß-d-glucosaminidase (NAG) activity and whole blood clotting time were evaluated before, during, and after completion of treatments. Results of urinalysis and measured urine NAG activity were also evaluated. RESULTS: Birds treated with meloxicam had a significant increase in number of WBCs and decrease in PCV from before to after treatment. The PCV also decreased significantly, compared with results for the control group; however, WBC count and PCV for all birds remained within reference ranges throughout the study. One parrot treated with meloxicam had a single high value for urine NAG activity. CONCLUSIONS AND CLINICAL RELEVANCE: Meloxicam administered orally at the dosage used in this study caused no apparent negative changes in several renal, gastrointestinal, or hemostatic variables in healthy Hispaniolan Amazon parrots. Additional studies to evaluate adverse effects of NSAIDs in birds will be needed.

Echocardiographic and radiographic findings in a cohort of healthy adult green iguanas (Iguana iguana).

OBJECTIVES: To describe characteristics of echocardiography and cranial coelomic radiography in a cohort of iguanas. ANIMALS: Twenty apparently healthy adult green iguanas (Iguana iguana) from a reptile sanctuary. METHODS: Physical examination, radiography, two-dimensional and color Doppler echocardiography were performed to assess cardiac structures and function, and any related normal or abnormal findings were recorded. RESULTS: Echocardiographic examination was possible without sedation and allowed visualization of the great vessels, atria, and ventricle. Some structures could not be evaluated in a minority of the iguanas due to individual differences in bony conformation and imaging quality. Suspected abnormal echocardiographic findings in 3 iguanas included pericardial effusion (n = 1) and enlarged caudal vena cava and/or sinus venosus (n = 2). Objective measurements were repeatable as assessed by within-subject coefficient of variation, and reliable as assessed by intra-observer intraclass correlation coefficient. Left atrial and ventricular measurements were significantly correlated with body weight. Valve regurgitation was common, with atrioventricular valve regurgitation present in 53% (9/17) and aortic or pulmonic valve regurgitation in 71% (12/17) of otherwise normal iguanas. A heart murmur was not appreciated during examination of any of the iguanas. Heart size cannot be measured radiographically due to superimposition and silhouetting of other coelomic structures. Echocardiographic or radiographic findings consistent with mineralization of the great vessels were present in 76% of iguanas (13/17). CONCLUSIONS: Echocardiography in iguanas is well tolerated without sedation and allowed both subjective evaluation and structural measurements. Valve regurgitation and great vessel mineralization were commonly observed in this cohort of apparently healthy adult iguanas.

Pharmacokinetics of buprenorphine hydrochloride following intramuscular and intravenous administration to American kestrels (Falco sparverius).

OBJECTIVE: To determine the pharmacokinetics of buprenorphine hydrochloride after IM and IV administration to American kestrels (Falco sparverius). ANIMALS: 13 healthy 3-year-old captive-bred American kestrels. PROCEDURES: Buprenorphine hydrochloride (0.6 mg/kg) was administered IM to all birds. Blood samples were collected at 9 times, ranging from 5 minutes to 9 hours after drug administration. Plasma buprenorphine concentrations were measured by use of tandem liquid chromatography-mass spectrometry. Pharmacokinetic parameters were determined by use of least squares linear regression and noncompartmental analysis of naïve pooled data. After a washout period of 2 weeks, the same dose of buprenorphine was administered IV to all birds and blood samples were collected at the same times after drug administration. RESULTS: Maximum plasma buprenorphine concentration was achieved within 5 minutes after IM administration. For IM administration, bioavailability was 94.8% and elimination half-life was 92.1 minutes. For IV administration, steady-state volume of distribution was 4,023.8 mL/kg, plasma clearance was 49.2 mL/min/kg, and elimination half-life was 105.5 minutes. CONCLUSIONS AND CLINICAL RELEVANCE: Buprenorphine was rapidly absorbed, and bioavailability was good after IM administration to American kestrels. Plasma buprenorphine concentrations were > 1 ng/mL for 9 hours after both IM and IV administration. These results, in combination with those of a pharmacodynamic study, suggested that the analgesic effects of buprenorphine could last at least 6 to 9 hours in this species. Further investigations of the duration of analgesic effects, multiple-dose protocols, and potential adverse effects of buprenorphine are warranted in American kestrels and other raptors.

Assessment of platelet-derived growth factor using A splinted full thickness dermal wound model in bearded dragons (Pogona vitticeps).

Wounds in reptiles are a common reason for presentation to a veterinarian. At this time there is limited information on effective topical medications to aid in wound closure. The objectives of this study were to translate the splinted, full-thickness dermal wound model, validated in mice, to the bearded dragon (Pogona vitticeps) and to determine the effect of topical becaplermin (BP), a platelet-derived growth factor (0.01%), on the rate of wound closure. Ten bearded dragons were anesthetized and two full-thickness cutaneous wounds were made on the dorsum of each lizard. Encircling splints were applied surrounding each wound and subsequently covered by a semi-occlusive dressing. Five lizards had one wound treated with BP and the adjacent wound treated with a vehicle control. Five additional lizards had one wound treated with saline and the second wound treated with a vehicle control. Wounds were imaged daily, and the wound area was measured using digital image analysis. The change in percentage wound closure over 17 days and the time to 50% wound closure was compared among the four treatment groups. There was no significant difference in wound closure rates between BP-treated and saline-treated wounds or in the time to 50% wound closure between any treatments. Vehicle-treated wounds adjacent to saline-treated wounds closed significantly slower than did BP (P < 0.010), saline (P < 0.001), and vehicle-treated wounds adjacent to BP-treated wounds (P < 0.013). Our preliminary study indicates that the splinted wound model, with modifications, may be used to determine wound closure rates in bearded dragons. When compared with saline, BP did not have a significant effect on wound closure rates, while the vehicle alone delayed wound closure. Histologic analysis of experimentally created wounds throughout the wound healing process is needed to further evaluate the effects of these treatments on reptile dermal wound healing.

Shape perception: complex contour representation in visual area V4.

A recent study has put forward a physiologically plausible population model that implements a parts-based shape-coding scheme for macaque visual area V4.