Clinicopathologic, gross necropsy, and histologic findings after intramuscular injection of carprofen in a pigeon (Columba livia) model.

To evaluate the pathologic effects of carprofen in a pigeon model (Columba livia), 52 young adult pigeons were used in a randomized control study design. Sixteen pigeons were randomly assigned to 1 of 3 treatment groups and received carprofen by intramuscular injection at dosages of either 2, 5, or 10 mg/kg once daily for 7 days. Four pigeons served as saline-injected controls. Four pigeons from each group and 1 control pigeon were randomly selected on days 2, 4, 6, and 8 to obtain blood samples and then were euthanatized and submitted for necropsy. Histologic lesions in pectoral muscle, liver, kidney, and digestive tract tissue samples were ranked in severity as 0, normal/not present; 1, minimal; 2, mild; 3, mild to moderate; 4, moderate; 5, moderate to marked; and 6, marked pathologic changes. Two-way analysis of variance (day x dose) and pairwise t tests revealed significant (P < or = .05) mild decreases in total protein and glucose concentrations and marked increases in aspartate aminotransferase and alanine aminotransferase enzyme activities after carprofen treatments. Gross lesions in carprofen-treated pigeons were pale injection sites (23/48 [47.9%]), mottled yellow livers (9/48 [18.8%]), and congestion of small intestines (7/48 [14.6%]). Liver, kidney, and muscle injection sites had significantly increased (P < or = .05) severity of histologic lesions. In pigeons, intramuscular administration of carprofen is associated with increased aspartate aminotransferase and alanine aminotransferase enzyme concentrations, gross lesions in muscle injection sites and liver, and histologic lesions in liver and muscle.

Relationship of hemoglobin concentration to packed cell volume in avian blood samples.

To determine whether a proportional relationship exists between hemoglobin (Hgb) concentration and pack cell volume (PCV) in avian blood samples, Hgb concentration measured by a point-of-care portable hemoglobinometer and corresponding PCV were determined in blood samples collected from 128 birds comprising 13 avian orders. For all birds evaluated and pooled across orders, a significant and consistent relationship was found between Hgb concentration and PCV, expressed as Hgb = 0.304 x PCV + 0.461. To determine whether the relationship of PCV and Hgb differs, 9 avian orders with n > or = 8 samples per order were analyzed by linear regression. Individual slopes for the 9 orders did not differ significantly (P = .44), indicating that a single slope can be used to model the avian Hgb to PCV relationship for these taxonomic orders. A single intercept can also be used, with the exception of order Phoenicopteriformes, which was the only intercept that was significantly different from 0 (P = .01). These results indicate that a simplified relationship of Hgb (g/dL) = 0.30 x PCV provides a reasonable estimate of Hgb concentration from the PCV of birds from the orders Anseriformes, Columbiformes, Falconiformes, Galliformes, Passeriformes, Psittaciformes, Sphenisciformes, and Strigiformes, but a separate relationship of Hgb = 0.217 x PCV + 6.69 might be warranted for the order Phoenicopteriformes.

Evaluation of gastrointestinal tract transit times using barium-impregnated polyethylene spheres and barium sulfate suspension in a domestic pigeon (Columba livia) model.

Barium impregnated polyethylene spheres (BIPS) are used in small animal medicine as an alternative to barium sulfate for radiographic studies of the gastrointestinal tract. To determine the usefulness of BIPS as an alternative to barium suspension in measuring gastrointestinal (GI) transit time for avian species, ventrodorsal radiographs were used to follow the passage of BIPS and 30% barium sulfate suspension through the GI tracts of domestic pigeons (Columba livia). Gastrointestinal transit times of thirty 1.5-mm BIPS administered in moistened gelatin capsules and 30% barium sulfate suspension gavaged into the crop were compared in 6 pigeons. Although the barium suspension passed out of the GI tract of all pigeons within 24 hours, the 1.5-mm BIPS remained in the ventriculus for 368.0 +/- 176.8 hours and did not clear the GI tract for 424.0 +/- 204.6 hours. Although the times for passage of BIPS and 30% barium sulfate suspension from the crop into the ventriculus were not significantly different (P = .14), the times for passage of BIPS from the ventriculus into the large intestine-cloaca and for clearance from the GI tract of the pigeons were significantly longer (P < .001) than for the 30% barium sulfate suspension. From the results of this study, we conclude that BIPS are not useful for radiographically evaluating GI transit times in pigeons and are unlikely to be useful in other avian species that have a muscular ventriculus. BIPS may or may not be useful for evaluating GI transit times in species that lack a muscular ventriculus.

Improvement in myocardial dysfunction in a hypothyroid dog.

An 8-year-old, male, Alaskan malamute was evaluated for a 2-week history of lethargy, inappetence, and distended abdomen. The dog was diagnosed with severe hypothyroidism, exhibited facial myxedema and had myocardial dysfunction with ascites and pleural effusion. Myocardial function improved and facial myxedema and effusions resolved with levothyroxine supplementation.

Retrospective evaluation of idiopathic hematuria and associated pathology in Grant's gazelles (Gazella granti): 10 cases.

Ten cases of hematuria in Grant's gazelle (Gazella granti) (two male and eight female) from five institutions were examined and the clinicopathologic data summarized. Five gazelles died spontaneously and five were euthanized. All gazelles had marked hematuria without pyuria. Mean age at the onset of clinical signs and time of euthanasia or death was 5.0 +/- 1.4 yr and 8.2 +/- 3.7 yr, respectively. The severity of clinical signs with hematuria ranged from episodes of chronic intermittent hematuria to marked dysuria, with urinary bladder rupture secondary to obstructive blood clots in one case. Submandibular edema was the most common associated clinical sign (five of 10 cases). Serum chemistries from eight gazelles obtained during hematuria episodes revealed hypocalcemia (8/8), hypoproteinemia (7/8), hypoalbuminemia (7/8), and hyperphosphatemia (6/8). Fifty percent of the gazelles (4/8) developed anemia over the course of hematuria episodes. Prothrombin times and partial thromboplastin times were presumed increased in two of four animals evaluated. The predominant histologic lesions in seven of 10 gazelles reviewed were vascular necrosis, vasculitis, and perivasculitis in the urinary tract. Lesions in necropsied gazelles were identified in the urinary bladder (7/10 gazelles), kidney (3/10), and ureter (3/10). Additional urinary tract lesions included tubulointerstitial nephritis (5/10 gazelles), hemorrhagic cystitis (4/10), renal tubular necrosis (4/10), and subacute renal infarcts (2/10). Polymerase chain reaction testing on paraffin-embedded urinary tract tissue for alcelaphine herpesvirus-1 and -2, ovine herpesvirus-2, bluetongue virus, and epizootic hemorrhagic disease virus was negative for the six cases tested. One gazelle that had been vaccinated for Leptospira interrogans had a titer to serovar icterohaemorrhagiae, but serum from the six other gazelles tested was negative for all L. interrogans serovars. No exposure to any toxic agent was identified. An underlying cause for vascular lesions associated with episodic hematuria in Grant's gazelles remains to be determined.

Seroprevalence of retrovirus in North American captive macropodidae.

Laboratory records of serology results from captive macropodidae sampled between 1997 and 2005 were reviewed to assess the seroprevalence of retrovirus exposure. Serum samples from 269 individuals (136 males, 133 females) representing 10 species of macropods housed in 31 North American captive collections were analyzed for retrovirus antibody using an indirect immunofluorescent assay. The prevalence of positive antibody titers comparing male versus female, between species, between age groups, and among animals with identified parentage was examined by nonparametric statistical analyses. Median age of animals at time of sample collection was 36 mo (range 2-201 mo). Total percentage seropositive was 20.4%. Serum antibody was detected in 31 of 47 (66.0%) tammar wallaby (Macropus eugenii), nine of 24 (37.5%) yellow-footed rock wallaby (Petrogale xanthopus), four of 11 (36.4%) swamp wallaby (Wallabia bicolor), 10 of 80 (12.5%) red-necked wallaby (Macropus rufogriseus), and one of 54 (1.9%) parma wallaby (Macropus parma). No individuals of western gray kangaroo (n=3) (Macropus fuliginosus), eastern gray kangaroo (n=19) (Macropus giganteus), common wallaroo (n=6) (Macropus robustus), red kangaroo (n=11) (Macropus rufus), or Matschie's tree kangaroo (n=14) (Dendrolagus matschiei) were positive for retrovirus antibody. These results demonstrate that five species of captive macropods have a history of exposure to retrovirus, with the highest percentage seropositive and highest statistical correlation in M. eugenii (pair-wise Fisher's exact test, alpha = 0.05). Additionally, one wild-caught M. eugenii was confirmed seropositive during quarantine period, indicating that retrovirus exposure may exist in wild populations.

Plasma uric acid, creatinine, and urea nitrogen concentrations after whole blood administration via the gastrointestinal tract in domestic pigeons (Columba livia).

To determine if blood administered to pigeons by gavage tube would simulate gastrointestinal hemorrhage in a noncarnivorous avian model, be digested in the gastrointestinal tract, and subsequently alter concentrations of plasma urea nitrogen, creatinine, or uric acid, blood from common peacocks (Pavo cristatus) was administered by gavage tube to 5 healthy domestic pigeons (Columba livia) at doses of 0.5, 1.0, 2.0, 4.0, and 8.0 ml/kg. No significant difference in plasma concentrations of urea nitrogen, creatinine, or uric acid was seen 4-6 hours after gavage. The findings did not support or rule out the presence of gastrointestinal blood in pigeons as a model for hemorrhage in noncarnivorous avian species.

Plasma pharmacokinetics of selamectin after a single topical administration in the American bullfrog (Rana catesbeiana).

Parasitism is common in wild and captive amphibians; however, pharmacologic data are lacking for anthelmintic drugs. This study was developed to determine the plasma pharmacokinetics of selamectin after topical administration in bullfrogs. Thirty-two adult American bullfrogs (Rana catesbeiana) were randomly assigned into eight groups of four with each group representing a different collection time point. Seven groups received selamectin (6 mg/ kg) topically and the remaining group served as the untreated control group. One group of frogs was euthanized and blood samples immediately collected on days 0 (control), 1, 5, 10, 15, 20, 25, and 30. Plasma was analyzed for selamectin using high performance liquid chromatography with fluorescence detection. Individual samples were analyzed, then data were reported as the mean of the four frogs at each time point. A histologic evaluation of the lung, liver, kidney, and skin tissues was performed and none of the frogs showed histologic evidence of toxicity due to selamectin administration. The mean peak plasma concentration was 162.5 +/- 42.3 ng/ml, area under the curve was 2,856 ng day/ml, mean residence time was 12.2 days, and disappearance half-life was 1.87 days. Based on the plasma pharmacokinetics, bullfrogs appear to absorb selamectin very efficiently, concentrations reach high levels in the plasma, and there were no apparent histologic effects from single dose administration.

B-cell lymphoma in a dog with ehrlichiosis (Ehrlichia canis) and systemic histoplasmosis (Histoplasma capsulatum).

A mixed breed dog treated for ehrlichiosis and systemic histoplasmosis developed a refractory thrombocytopenia. When an abdominal mass was detected, exploratory laparotomy and biopsies confirmed lymphoma, which on immunohistochemical stains was determined to be of B-cell origin. Conceivably, the B-cell lymphoma in this dog was associated with chronic inflammation from ehrlichiosis, histoplasmosis, or both.

Epitheliotropic lymphoma in a captive bontebok (Damaliscus pygargus).

A 16-yr-old, female, captive-bred bontebok (Damaliscus pygargus) estimated to be 75 kg, was presented with a 1-mo history of chronic diarrhea and weight loss. A cause for the deteriorating condition was not found antemortem, and the bontebok was humanely euthanatized when it failed to respond to empirical therapy. On necropsy, numerous nodules were present on the pleural surfaces and within the lung parenchyma, the pancreas appeared inflamed and fibrotic. Histologic examination revealed lymphoma in the mesenteric lymph nodes, alimentary tract, reproductive tract, and liver. In the small and large intestine, rumen, esophagus, bile duct, and vagina, the neoplastic cells had a tropism for epithelium. The neoplastic cells within the epithelium and subepithelium of the alimentary tract stained positively for CD3, consistent with T cell differentiation.

A new species of Cytauxzoon from Pallas' cats caught in Mongolia and comments on the systematics and taxonomy of piroplasmids.

DNA was extracted and the 18S ribosomal RNA gene was amplified and sequenced from the blood of 2 Pallas' cats (Otocolobus manul) infected with small intraerythrocytic piroplasms. Sequences of the parasite were found to be identical with that of a previously reported Cytauxzoon-like piroplasm from a Pallas' cat. Phylogenetic analyses of the parasite DNA sequences obtained from the 3 Pallas' cats to other piroplasms revealed a sister group relationship to C. felis. The mean corrected percent sequence divergence between the Pallas' cat parasite and C. felis was 1.490%, which is greater than that for most other piroplasms in which species status has been accepted. On the basis of the sequence variation, we propose to name the Pallas' cat parasite C. manul. Phylogenetic analyses of C. manul also revealed a close relationship with the Spanish Cytauxzoon-like isolate because they exhibited only 0.389% sequence divergence, yet these sequences exhibit a mean of 1.690% sequence divergence from the New World isolate of C. felis. Our phylogenetic analyses also revealed several taxonomic problems that have impeded the development of a classification that accurately reflects evolutionary history of piroplasms. As currently arranged, Babesia and Theileria are paraphyletic taxa and are in need of reorganization.

Blood thiamine values in captive adult African lions (Panthera leo).

Heparinized whole-blood samples from 22 adult African lions (Panthera leo) fed diets considered nutritionally adequate in 10 American Zoo and Aquarium Association member zoos in North America were provided for this study. Blood thiamine values were estimated using a standard microbiological assay method. The mean +/- standard deviation for blood thiamine values was 249.3 +/- 43.5 nmol/L with a range in values from 160 to 350 nmol/L after exclusion of one outlier. There were no differences (P > 0.05) in the mean blood thiamine values of male and female lions, or of lions that were over and under 10 yr of age. This range (160 to 350 nmol/L) is proposed as a reasonable estimate of the expected range in blood thiamine values for captive adult African lions as currently fed in North American zoos.

Presumed primary thiamine deficiency in a young African lion (Panthera leo).

A 1-yr-old intact male African lion (Panthera leo) fed only beef muscle meat was evaluated for episodes of hypermetric ataxia, generalized weakness and tonic-clonic front limb movements. A hemogram, biochemical profile, blood lead, electrocardiogram, survey radiographs, and brain computed tomography were normal. Cerebral spinal fluid analyses suggested mild inflammation. Acetylcholine receptor antibody and serologic tests for all infectious agents tested were negative. Clinical signs resolved completely 9 days after instituting oral thiamine (3 mg/kg/day) and a completely nutritional diet. This lion's pretreatment thiamine blood value (11 nmol/L) was markedly lower than that of a healthy lion (191 nmol/L) and a proposed reference range for adult African lions (160-350 nmol/L). The lion remained clinically normal 2 yr later when his blood thiamine value was 340 nmol/L. African lions can develop clinical primary thiamine deficiency and may respond favorably when thiamine treatment and adequate diet are instituted prior to irreversible neuronal necrosis.

Serologic responses after vaccination of fennec foxes (Vulpes zerda) and meerkats (Suricata suricatta) with a live, canarypox-vectored canine distemper virus vaccine.

Fennec foxes (Vulpes zerda) and meerkats (Suricata suricatta) are considered to be susceptible to canine distemper virus (CDV) infection. Although no definitive clinical cases of natural CDV infections have been reported, mortalities due to CDV have been suspected and are reported in other closely related species. A commercially available monovalent, live, canarypox-vectored CDV vaccine induced neutralizing antibody titers that were maintained for at least a year in both fennec foxes and meerkats.

Paresis secondary to an extradural hematoma in a Sumatran tiger (Panthera tigris sumatrae).

A 15-yr-old female Sumatran tiger (Panthera tigris sumatrae) was presented to the Boren Veterinary Medical Teaching Hospital at Oklahoma State University with a 3-wk history of progressive hind limb weakness. Neurologic evaluation was limited to review of videotape that demonstrated weakness and ataxia with conscious proprioceptive deficits of the tiger's pelvic limbs. Spinal radiography demonstrated disc space narrowing, and myelography demonstrated a large extradural compressive lesion at the level of L2-3. Computed tomography did not reveal bone involvement. Surgery was performed to decompress the spinal cord and obtain a definitive diagnosis. A right hemilaminectomy was performed after a dorsal approach to the lumbar spine. Histologic examination of the mass revealed a consolidated extradural spinal hematoma, presumed to be secondary to intervertebral disc herniation. Despite incomplete resection of the mass and plastic deformation of the spinal cord, the tiger returned to normal ambulation within 3 wk of surgical decompression.

Hematology and plasma biochemistry of captive puna ibis (Plegadis ridgewayi).

Normal hematology and plasma biochemistry values are reported for a single captive population of 14 puna ibises (Plegadis ridgewayi). The natural biology and conservation status of this species is virtually unknown and it is considered a vulnerable species in parts of South America. The values presented here may be useful to clinicians or wildlife managers working with puna ibises.

Use of a hybrid external skeletal fixator for repair of a periarticular tibial fracture in a Patagonian cavy.

An 8-week-old female Patagonian cavy was examined because of acute right hind limb lameness; radiography revealed a moderately displaced, comminuted fracture of the proximal third of the tibia. The fracture was stabilized with a hybrid external skeletal fixator. Two Kirschner wires were placed in the main proximal fragment, parallel to the tibial plateau and at right angles to each other. These wires were connected to a partial circular external fixator ring. Three half pins were placed in the distal fragment, and a straight connecting rod positioned on the medial side of the limb was connected to these pins and the fixator ring. A second connecting rod was positioned on the craniomedial side of the limb and was connected to the fixator ring and a fourth half pin in the distal fragment. The fracture healed without complications, and the fixator was removed 3 weeks after surgery. Hybrid external skeletal fixators combine the benefits of circular and linear external skeletal fixation methods, enabling rigid fixation of periarticular long bone fractures without adversely affecting mobility of the adjacent joint.

Immunodeficiency associated with multiple concurrent infections in captive Pallas' cats (Otocolobus manul).

Five neonatal Pallas' cats (Otocolobus manul) at the Oklahoma City Zoo died from toxoplasmosis with concurrent herpesvirus infection. These multiple infections suggested underlying immunodeficiency, perhaps caused by concurrent infection with feline immunodeficiency virus (FIV); so blood samples were collected for serology, serum protein electrophoresis, lymphocyte proliferation assays, and cytokine analysis by reverse transcriptase-quantitative competitive polymerase chain reaction (RT-qcPCR). Resulting data were compared with data from FIV-infected and control domestic short-haired cats. In addition, peripheral blood mononuclear cell cultures were propagated to detect FIV virus by both RT-qcPCR and detection of reverse transcriptase activity. Serum protein electrophoresis showed that four of six Pallas' cats had increased alpha, globulins. At least two Pallas' cats had decreased lymphoproliferation responses to mitogen. and all three tested animals exhibited defective interleukin-12 gene expression. Although these clinical and laboratory findings suggested an immunodeficiency syndrome, FIV infection could not be confirmed. On the basis of repeated blood test results, it can be concluded that nutritional, metabolic, or other systemic problems probably did not contribute to the disease syndrome. Further investigation of other possible causes of immunodeficiency, including a possible genetic component, in this population is needed.

An intraerythrocytic small piroplasm in wild-caught Pallas's cats (Otocolobus manul) from Mongolia.

During the quarantine examination of four Pallas's cats (Otocolobus manul) imported from Mongolia in October and December 2000, intraerythrocytic piroplasms were detected on Wright-Giemsa stained blood films that were morphologically indistinguishable from other small piroplasms of felids. Further characterization of this unknown organism via polymerase chain reaction amplification, sequencing of a portion of the 18S nuclear small subunit rRNA gene, and comparisons with orthologous sequences from other piroplasms, revealed similarity to Cytauxzoon felis. This is the first report of naturally occurring erythroparasitemia in Pallas's cats and the first documented case of naturally occurring piroplasm infections in a free-ranging felid from Mongolia.

Spinal compression due to atlantal vertebral malformation in two African lions (Panthera leo).

Two young (14-mo-old and 6-mo-old), unrelated, male African lions (Panthera leo) were presented to the Veterinary Teaching Hospitals of Oklahoma State University and Kansas State University with progressive ambulatory difficulty. In both cases, limited neurologic evaluation demonstrated pelvic limb paresis and ataxia with conscious proprioceptive deficits. Spinal imaging showed nearly identical lesions in both cases. Radiography and myelography demonstrated cervical stenosis secondary to atlantal (C1) malformation producing a dorsoventral deformity of the laminar arch with atlantoaxial spinal cord compression between the ventrally displaced laminar arch of the atlas and the underlying odontoid process of C2. Computed tomography of the atlanto-axial junction confirmed cervical stenosis and cord compression, showing flattening of the spinal cord between the laminar arch of C1 and the dens of C2. Decompressive surgery consisting of dorsal laminectomy of C1 was performed. Each lion demonstrated progressive improvement of neurologic status to recovery of normal ambulation after surgical intervention. Neurologic disease in large captive felids is rare; atlanto-axial spondylomyelopathy has not been reported previously.