Natalie D. Mylniczenko

Evaluation of critical care blood analytes assessed with a point-of-care portable blood analyzer in wild and aquarium-housed elasmobranchs and the influence of phlebotomy site on results.

OBJECTIVE To establish reference ranges for critical care blood values measured in wild and aquarium-housed elasmobranchs by use of a point-of-care (POC) blood analyzer and to compare values on the basis of species category (pelagic, benthic, or intermediate) and phlebotomy site. DESIGN Cross-sectional study. ANIMALS 66 wild and 89 aquarium-housed elasmobranchs (sharks and rays). PROCEDURES Aquarium-housed elasmobranchs were anesthetized for sample collection; wild elasmobranchs were caught via hook and line fishing, manually restrained for sample collection, and released. Blood was collected from 2 sites/fish (dorsal sinus region and tail vasculature) and analyzed with the POC analyzer. Reference values of critical care blood analytes were calculated for species most represented in each population. Values were compared on the basis of species categorization (pelagic, intermediate, or benthic) and collection site. RESULTS Oxygen saturation and circulating concentrations of lactate and glucose were significantly different among aquarium-housed pelagic, intermediate, and benthic species. Lactate concentration was significantly different among these categories in wild elasmobranchs. Significant differences were detected between samples from the 2 collection sites for all blood analytes. In both study populations, pH and lactate values were infrequently < 7.2 or > 5 mmol/L, respectively. CONCLUSIONS AND CLINICAL RELEVANCE Brevity of handling or chemical restraint may have reduced secondary stress responses in fish because extreme variations in blood analyte values were infrequent. Sample collection site, species categorization, acclimation to handling, and restraint technique should be considered when assessing values obtained with the POC analyzer used in this study for blood analytes and immediate metabolic status in elasmobranchs.

DIAGNOSIS AND TREATMENT OF SARCOCYSTIS NEURONA IN A CAPTIVE HARBOR SEAL (PHOCA VITULINA)

Abstract A captive harbor seal (Phoca vitulina) presented with partial anorexia, ataxia, and head bobbing, which progressed to complete anorexia, lethargy, and persistent whole-body intention tremors within several days. Response to treatment with ponazuril, serology, and cerebrospinal fluid analysis supported a diagnosis of Sarcocystis neurona. Analysis of serum levels for ponazuril indicated that therapeutic levels could be achieved at a dosage of 5 mg/kg p.o. s.i.d., whereas clinical response was improved at a dosage of 10 mg/kg. Several months after initiation of antiprotozoal therapy, the neurologic signs resolved, although rare intermittent tremors were seen with significant exertion.

SUCCESSFUL TREATMENT OF MANDIBULAR SQUAMOUS CELL CARCINOMA IN A MALAYAN SUN BEAR (HELARCTOS MALAYANUS)

Abstract An adult, female Malayan sun bear (Helarctos malayanus) was diagnosed with squamous cell carcinoma of the rostral mandible. Initial treatment included bilateral mandibulectomy rostral to the lingual frenulum followed by intra- and perilesional cisplatin injections. Recovery after the procedure was uneventful and the Malayan sun bear adapted well to a shortened mandible. Histopathology indicated incomplete surgical excision of the tumor; therefore, radiation therapy was instituted weekly for four treatments at 2 Gy in parallel opposed fields (total 4 Gy each treatment) with one additional cisplatin treatment. Two years after initial presentation, the animal showed no recurrence of neoplasia.

Colonic obstruction in three captive reticulated giraffe (Giraffa camelopardalis reticulata).

Abstract Fatal colonic obstructions were diagnosed in three captive, adult, reticulated giraffe (Giraffa camelopardalis reticulata). Clinical presentations varied, but all cases displayed decreased activity, anorexia, and considerably decreased fecal production, consistent with intestinal obstruction. Case 1 was diagnosed at necropsy with a phytobezoar obstructing the spiral colon. Case 2 was diagnosed at necropsy with a fecal impaction of the colon. Case 3 was diagnosed during surgery with colonic ileus. Cases 2 and 3 underwent surgical intervention but were markedly compromised by the time of surgery and died during surgery or 24 hr postoperatively. Gastrointestinal obstruction, requiring aggressive supportive care and early surgical intervention, should be considered in giraffe in which anorexia and substantially decreased fecal production are observed. Abdominal exploratory surgery will likely be necessary for diagnosis and treatment. Based on a small number of cases, gastrointestinal obstruction has a poor prognosis in giraffe.

PHARMACOKINETIC EVALUATION OF MELOXICAM AFTER INTRAVENOUS AND INTRAMUSCULAR ADMINISTRATION IN NILE TILAPIA (OREOCHROMIS NILOTICUS)

Abstract Critically evaluating the pharmacokinetic behavior of a drug in the body provides crucial information about how to effectively treat a patient. Pharmacokinetic studies that exist in fish have primarily focused on drugs used to treat infectious disease, with minimal attention given to analgesic drugs. The objective of this study was to determine the pharmacokinetics of meloxicam (1 mg/kg) in Nile tilapia (Oreochromis niloticus) (n = 12). A single dose of meloxicam was administered either i.v. or i.m. Blood samples were obtained at predetermined times after drug injection. Plasma meloxicam concentrations were determined by a validated liquid chromatography/mass spectrometry method, and noncompartmental pharmacokinetic analysis was performed. The mean peak plasma concentration after i.m. injection was 1.95 μg/ml. The mean terminal half-life of meloxicam after i.v. and i.m. administration was 1.36 and 1.8 hr, respectively. The area under the plasma concentration-versus-time curve extrapolated to infinity was 11.26 hr·μg/ml after i.v. administration and 5.72 hr·μg/ml after i.m. administration. Bioavailability of meloxicam after i.m. administration was approximately half that of i.v. administration. Elimination was rapid in both the i.m. and i.v. routes of administration, suggesting that maintaining clinically relevant plasma concentrations may be difficult using this dose. This study represents the first pharmacokinetic evaluation of a nonsteroidal anti-inflammatory drug in a fish species, and further studies evaluating efficacy are needed.

Morphologic evidence suggestive of hypertension in western gray kangaroos (Macropus fuliginosus).

Marked renal vascular changes, suggestive of hypertension, were present in adult western gray kangaroos (Macropus fuliginosus) from a single facility over a 14-year period. A subset of these kangaroos also had vague clinical nervous system deficits, including blindness. To characterize the vascular lesions, determine prevalence, and document other changes, case histories and archival tissue sections from 21 adult kangaroos (8 male, 13 female) that died or were euthanatized between 1994 and 2008 were reviewed. Relevant lesions included increased thickness of the renal arteriolar tunica media with smooth muscle hypertrophy and/or hyperplasia, accumulation of extracellular matrix within arterioles, increased vascular tortuosity, and varying degrees of juxtaglomerular hyperplasia. Renal tissue from two more severely affected animals was further examined by transmission electron microscopy, highlighting arteriolar endothelial cell hypertrophy and disruption of the medial architecture. Hypertrophy of arteries and arterioles in other organ systems was also present (3/21), including vessels in the brain and spinal cord of one animal with clinical neurologic signs. Four kangaroos had antemortem retinal detachment, a potential sequel of hypertension in humans and domestic mammals. The cause of these vascular lesions in this mob is uncertain. Lesions were not associated with an infectious disease process, age, underlying renal disease, or thyroid abnormalities. In the absence of other causes, hypertension was a differential. Further investigation into clinical significance and predisposing factors, such as genetics and diet, is warranted.

Dilated Ureters, Renal Dysplasia, and Chronic Renal Failure in an African Elephant (Loxodonta africana)

Abstract:  An ultrasonographic reproductive health examination of a 26-yr-old female African elephant (Loxodonta africana) revealed bilateral ureteral wall thickening and dilatation. On ultrasonographic examination, the bladder and both ureters were normal near the trigone; however, the cranial-most aspect of each ureter was dilated and thickened for a length of 30–50 cm. The same month, elevated blood creatinine (3.0 mg/dl), and urine protein-creatinine ratio (4.0) were observed. Chronic renal failure was diagnosed based on these abnormalities, and the persistent ureteral dilatation was seen on subsequent ultrasound examinations. Complete blood cell counts, serum chemistries, and urinalyses remained relatively unchanged until 24 mo after diagnosis, at which time azotemia, hypophosphatemia, and hypercalcemia (including elevated ionized calcium) developed. Hydronephrosis of both kidneys and prominent sacculation of the left ureter were noted on ultrasonographic examination. Lethargy, ventral edema, and oral mucosal ulceration acutely developed 30 mo after diagnosis. Although blood urea nitrogen remained elevated, creatinine, total calcium, and ionized calcium returned to within reference ranges at that time. Due to rapid clinical decline and grave prognosis, humane euthanasia was elected. Bilateral ureteral dilatation, dysplasia of the right kidney, and chronic nephritis of the left kidney were identified postmortem.

Seasonal dynamics of agonistic behavior and hormones in an ex situ all-male colony of large flying foxes

Large flying foxes (Pteropus vampyrus) are a socially complex species. In situ colonies typically comprise thousands of individuals in small harems of one male to many females. In ex situ environments, all-male colonies are becoming more common due to a surplus of males in the population. There is limited information describing the hormonal and behavioral patterns of all-male colonies during the breeding season. We assessed seasonal changes in hormones and behavior in an all-male colony of 12 large flying foxes at Disneys Animal Kingdom® . We validated hormone assays using morning urine and fecal samples to assess seasonal changes in excreted immunoreactive testosterone and glucocorticoid metabolites. We collected behavior data using an all-occurrence method, recording agonistic behaviors related to territorial defense (hooking, biting, wing flexing, vocalizing, and wrestling), and sexual behavior (mounting and frontal grabbing). Results indicated that (i) we could reliably measure testosterone and glucocorticoid metabolites concentrations from fecal and urine samples collected from individual bats; (ii) there were distinct relationships between changes in levels of agonism and hormone concentrations throughout the year; and (iii) three agonistic behaviors (chasing, wrestling, and open-mouth threat) peaked prior to the increase in testosterone and glucocorticoid hormones measured during the breeding season. These three behaviors could potentially be used as early indicators to signal the onset of the breeding season and allow time to implement ex situ management changes to reduce the incidence of agonism between individuals.

A SEROLOGIC AND POLYMERASE CHAIN REACTION SURVEY OF EQUINE HERPESVIRUS IN BURCHELL'S ZEBRAS (EQUUS QUAGGA), HARTMANN'S MOUNTAIN ZEBRAS (EQUUS ZEBRA HARTMANNAE), AND THOMSON'S GAZELLES (EUDORCAS THOMSONII) IN A MIXED SPECIES SAVANNAH EXHIBIT

Abstract Reports of equine herpesvirus (EHV) 1 and EHV-9 causing clinical disease in a wide range of species have been well documented in the literature. It is thought that zebras are the natural hosts of EHV-9 both in the wild and in captive collections. Concerns about potential interspecies transmission of EHV-1 and EHV-9 in a mixed species savannah exhibit prompted serologic and polymerase chain reaction surveys. Eighteen Burchells zebras (Equus quagga), 11 Hartmanns mountain zebras (Equus zebra hartmannae), and 14 Thomsons gazelles (Eudorcas thomsonii) cohabitating the same exhibit were examined for EHV-1 virus neutralization titers, and evidence of virus via EHV 1-5 polymerase chain reactions. None of the animals had previous exposure to vaccination with EHV-1 or EHV-4. All tested zebras had positive EHV-1 titers, ranging from 4 to 384. All zebras and Thomsons gazelles had negative polymerase chain reaction results for all targeted equine herpesviruses. EHV-9–specific assays are not available but EHV-1, EHV-4, and EHV-9 cross-react serologically. Positive serology results indicate a potential latent equine herpesvirus in the zebra population, which prompted initiation of an equine herpesvirus vaccine protocol, changes in pregnant zebra mare management, and equine herpesvirus polymerase chain reaction screening prior to shipment to or from the study site.