PHARMACOKINETICS OF ORAL FLUNIXIN MEGLUMINE, MELOXICAM, OR GABAPENTIN IN THREE BLACK RHINOCEROS (DICEROS BICORNIS)

Pharmacokinetics of single, separate doses of IV flunixin meglumine (1 mg/kg), IV meloxicam (0.5 mg/kg), oral flunixin meglumine (1 mg/kg), oral meloxicam (1 mg/kg), and oral gabapentin (15 mg/kg) in three adult black rhinoceroses (Diceros bicornis) were determined from serial blood collection made over 72 h. The concentration versus time profiles were analyzed for each drug and route in each individual rhinoceros, and individual pharmacokinetic parameters were calculated for each medication administered. Meloxicam had near complete bioavailability in each trial, while flunixin meglumine was generally lower. Oral meloxicam was noted with similar half-life values between all animals (range 9.22-14.52 h) tested, while oral gabapentin had a larger range (range 10.25-24.85 h). Oral flunixin meglumine achieved a lower C_max (range 170.67-664.38 ng/ml) in this study compared with the mean C_max (1,207 ng/ml) reported in a similar study in white rhinoceroses (Ceratotherium simum), but some overlap in range of values was noted. Oral flunixin meglumine T_max (range 1.05-10.78 h) and half-life (range 3.88-14.85 h) values in black rhinoceroses was similar to mean values reported in white rhinoceroses (3 and 8.3 h, respectively).

Shell Lesions Associated With Emydomyces testavorans Infection in Freshwater Aquatic Turtles

A newly described onygenalean fungus, Emydomyces testavorans, has been isolated from ulcerative shell and skin lesions of freshwater aquatic chelonians. To investigate the shell lesions associated with infection and determine if any lesional features were unique to E. testavorans, tissues from turtles housed in zoological institutions (n = 45) in the United States and free-living turtles (n = 5) submitted for diagnostic biopsy or necropsy were examined. Free-living turtles were from geographically distinct habitats in Florida (n = 1) and Washington (n = 4) at the time of sampling. Histologic shell sections were evaluated for the presence or absence of specific lesional features. Infection with E. testavorans was evaluated in all cases by screening GMS (Grocott-Gomori's methenamine silver)-stained histologic sections for the presence of morphologically consistent fungi and by quantitative PCR (polymerase chain reaction) on representative frozen tissue or formalin-fixed paraffin-embedded sections. Additionally, culture was performed for 15 cases with available fresh/frozen tissue. In total, there were 17 PCR-confirmed E. testavorans cases, 29 cases with morphologically consistent fungi on GMS-stained sections, and 21 cases of shell lesions without histologic or molecular evidence of E. testavorans infection. Epithelial inclusion cysts, defined as cystic structures within the dermis lined by keratinized stratified squamous epithelium and containing necrotic bone and keratin debris, were significantly (P < .01) associated with E. testavorans infection. Other significantly associated shell lesions included squamous metaplasia, hyperkeratosis, inflammation, and osteonecrosis (P < .05). This study identified characteristic shell lesions associated with E. testavorans infection. Further studies to prove causality are needed.

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.

Novel Herpesvirus Associated With Oropharyngeal Squamous Cell Carcinoma in Smooth Green Snakes (Opheodrys vernalis)

During a 19-month period, 5 smooth green snakes (Opheodrys vernalis) maintained as an ex situ conservation colony presented with rapid clinical progression of locally invasive oropharyngeal squamous cell carcinoma. All 5 originated from the same wild source and were housed together or in close proximity. An infectious cause was considered likely, and nested conventional polymerase chain reaction (PCR) and in situ hybridization confirmed the presence of a novel alphaherpesvirus, Opheodrys herpesvirus 1, in the neoplastic tissue in 4 of the 5 snakes. Retrospective screening of previously submitted smooth green snakes by in situ hybridization did not detect virus in prior submissions from the colony. This report documents molecular characterization of an ophidian herpesvirus as well as colocalization of its viral nucleic acid with neoplastic transformation in snakes.

Human metapneumovirus infection in chimpanzees, United States

Zoonotic disease transmission and infections are of particular concern for humans and closely related great apes. In 2009, an outbreak of human metapneumovirus infection was associated with the death of a captive chimpanzee in Chicago, Illinois, USA. Biosecurity and surveillance for this virus in captive great ape populations should be considered.

Effects of ultracentrifugation on plasma biochemical values of prefledged wild peregrine falcons (Falco peregrinus) in northeastern Illinois

Centrifugation is performed on whole blood samples to obtain serum or plasma for biochemical analysis. Although blood samples centrifuged in a microhematocrit tube may maximize recovery of plasma from small-volume samples, plasma biochemical values from such samples have been implicated as causing erroneous results. To compare blood biochemical values obtained by microhematocrit centrifugation and centrifugation with a commercial tilt-rotor machine, blood samples were collected from peregrine falcon (Falco peregrinus) eyases aged 32-40 days (n=51). The samples were separated into 2 equal aliquots with 1 aliquot centrifuged in a tilt-rotor machine and the other aliquot ultracentrifuged in microhematocrit tubes. Separated plasma from both processes was sent to a commercial veterinary reference laboratory for routine clinical biochemical analysis. No significant differences were found in the biochemical results of the paired samples by the 2 centrifugation methods. These results show that the centrifugation method has no effect on the plasma quality for biochemical analysis in young peregrine falcons.

Blood groups in the Species Survival Plan®, European endangered species program, and managed in situ populations of bonobo (Pan paniscus), common chimpanzee (Pan troglodytes), gorilla (Gorilla ssp.), and orangutan (Pongo pygmaeus ssp.)

Blood groups of humans and great apes have long been considered similar, although they are not interchangeable between species. In this study, human monoclonal antibody technology was used to assign human ABO blood groups to whole blood samples from great apes housed in North American and European zoos and in situ managed populations, as a practical means to assist blood transfusion situations for these species. From a subset of each of the species (bonobo, common chimpanzee, gorilla, and orangutans), DNA sequence analysis was performed to determine blood group genotype. Bonobo and common chimpanzee populations were predominantly group A, which concurred with historic literature and was confirmed by genotyping. In agreement with historic literature, a smaller number of the common chimpanzees sampled were group O, although this O blood group was more often present in wild-origin animals as compared with zoo-born animals. Gorilla blood groups were inconclusive by monoclonal antibody techniques, and genetic studies were inconsistent with any known human blood group. As the genus and, specifically, the Bornean species, orangutans were identified with all human blood groups, including O, which had not been reported previously. Following this study, it was concluded that blood groups of bonobo, common chimpanzees, and some orangutans can be reliably assessed by human monoclonal antibody technology. However, this technique was not reliable for gorilla or orangutans other than those with blood group A. Even in those species with reliable blood group detection, blood transfusion preparation must include cross-matching to minimize adverse reactions for the patient.

Two cases of atypical mycobacteriosis caused by Mycobacterium szulgai associated with mortality in captive African elephants (Loxodonta africana)

Mycobacterium szulgai was associated with mortality in two captive African elephants (Loxodonta africana) housed at Lincoln Park Zoo. The first elephant presented with severe, acute lameness of the left rear limb. Despite extensive treatments, the animal collapsed and died 13 mo after initial presentation. Necropsy revealed osteomyelitis with loss of the femoral head and acetabulum and pulmonary granulomas with intralesional M. szulgai. The second elephant collapsed during transport to another institution with no premonitory clinical signs. This animal was euthanized because of prolonged recumbency. Granulomatous pneumonia with intralesional M. szulgai was found at necropsy. Two novel immunoassays performed on banked serum samples detected antibody responses to mycobacterial antigens in both infected elephants. It was not possible to determine when the infection was established or how the elephants were infected. When reviewing the epidemiology of this organism in humans, however, transmission between elephants seemed unlikely because human-to-human transmission of this organism has never been reported and a third elephant in the herd was not affected. In addition to Mycobacterium bovis and Mycobacterium tuberculosis, atypical mycobacterial organisms need to be considered potentially pathogenic in elephants.

Taxus sp. intoxication in three Francois' langurs (Trachypithecus francoisi)

Three Francois' langurs (Trachypithecus francoisi) were found dead, without previous clinical signs, over a 48-hour period at a zoological institution after transfer to a new exhibit. A hybrid yew shrub (Taxus baccata X T. cuspidata) was found in close proximity to the exhibit perimeter fence. Despite clinical suspicion of yew intoxication, thin-layer chromatography performed on gastric contents was negative. However, microscopic examination of gastric contents revealed multiple yew fragments, and taxine alkaloids were detected by gas chromatography and mass spectrometry of the gastric contents to confirm yew intoxication. Acute death of the animals prevented treatment. The fourth langur in the collection survived, most likely because of its low rank in the troop's hierarchy, with a suspected small amount or none of the plant ingested. To the authors' knowledge, this case report is the first yew intoxication documented in a nonhuman primate species. Taxus spp. intoxication is an often fatal condition reported in domestic animals and humans. In comparison with these species, mortality appeared delayed in the Francois' langurs, most likely because of their unique gastrointestinal anatomy, with both foregut and colonic fermentation. Plant intoxication should be a differential diagnosis when multiple acute deaths are observed after recent introduction to a new enclosure.

Tracheitis associated with Bordetella bronchiseptica in a polar bear (Ursus maritimus)

A male polar bear (Ursus maritimus) was diagnosed with tracheitis associated with Bordetella bronchiseptica that was cultured from an endotracheal sample of thick mucopurulent exudate. The condition responded to oral amoxicillin/clavulanic acid, and clinical signs of inappetence, depression, dysphagia, and tussis were resolved. One week after this presentation, a female conspecific presented with similar clinical signs, suggesting a transmissible nature of the disease or the same source of infection. The source of infection remains unknown.

CESTODE CYSTS IN TWO AFRICAN GIANT POUCHED RATS (CRICETOMYS GAMBIANUS)

Multiple cestode cysts identified as Taenia serialis were present in the bodies of two wild-caught African giant pouched rats (Cricetomys gambianus) at necropsy. This rodent species can be an intermediate host for this parasite. Exotic rodents kept as pets in the United States may be affected.

Pancreatic islet fibrosis in rock hyrax (Procavia capensis), Part 2: Pathology, immunohistochemistry, and electron microscopy

Pancreatic islet fibrosis with varying degrees of islet cell hyperplasia or islet effacement was diagnosed histologically in 19 rock hyraxes (Procavia capensis) from seven zoological parks. Some, but not all, affected hyraxes were from a common lineage. The condition was associated with apparent hyperglycemia in seven and diabetes mellitus in two. Immunohistochemistry revealed hyperplasia of beta, alpha, and delta cells proportional to the degree of the fibrosis. Electron microscopy revealed collagen deposition and fibroplasia within and around the islets. Special stains and electron microscopy were negative for the presence of amyloid. Beta cell depletion was never identified. The condition has morphologic features that resemble islet fibrosis of human infants born to diabetic mothers.

Pancreatic islet fibrosis in rock hyraxes (Procavia capensis), Part 1: Case histories, clinical pathology, and epizootiology

Two adult female rock hyraxes (Procavia capensis) at the Dallas Zoo were confirmed with spontaneous diabetes mellitus from 1997-2000, whereas a third animal with a similar clinical presentation never became hyperglycemic. The pancreas in all three animals showed pancreatic islet fibrosis (PIF). Retrospective examination of medical records for rock hyraxes acquired by this collection or born into it from 1991-2002 identified eight more animals affected with PIE All affected animals, including three males and eight females, were 1-7 yr of age and presented either with vague clinical signs of soft feces and rough hair coat or were acutely moribund or dead. Clinical pathology data was available for seven of the animals before onset of overt clinical signs and revealed inappropriate hyperglycemia in six, as well as elevated serum concentrations of creatine phosphokinase, amylase, and lipase in all seven animals. Pedigree evaluation did not support a familial pattern for PIE Review of the histopathology findings from nine other zoologic collections with rock hyrax deaths during the study period identified six institutions with 12 additional cases genetically unrelated to the incident collection. Histopathology and viral serology did not support an infectious cause. Analysis of serum anti-islet and anti-insulin antibodies did not suggest autoimmune disease, and none of the animals had known exposure to toxic substances. Limited nutritional analyses did not support a nutritional basis for the condition, and the cause for PIF remains unknown.

Marsupial care and husbandry

Although startlingly different in anatomy and physiology from the placental mammals common to private veterinary practice, clinical care for marsupial mammals can be approached from similar perspectives. Marsupials remain undomesticated animals with challenging needs in diet and care that must consider their native environment to be successful. As wild animals, veterinary care and clinical problems of marsupials as pets can present from sources of stress, restraint, and husbandry. Veterinary professional scan prevent many of these concerns by advising caretakers on appropriate care and feeding of these species.

Idiopathic hemorrhagic vasculopathy syndrome in seven black rhinoceros

Idiopathic hemorrhagic vasculopathy syndrome (IHVS) was diagnosed in 7 black rhinoceros; this newly described syndrome is characterized by severe body swelling in conjunction with a rapid and profound decrease in Hct. The disorder may be acute or chronic, may recur, and is potentially fatal. Five of the rhinoceros survived an initial episode of IHVS, and 2 of these 5 survived a recurrent episode of IHVS. Two rhinoceros died during treatment of IHVS. Treatment protocols varied, but all 7 rhinoceros received broad-spectrum antibiotics, because an infectious cause was suspected. All rhinoceros also received nonsteroidal antiinflammatory drugs and supportive care. Idiopathic hemorrhagic vasculopathy syndrome has many similarities to other vasculopathies of domestic animals, such as equine purpura hemorrhagica, but it also appears to have unique identifying features. It has been hypothesized that IHVS may be an immune response to an as yet unidentified infectious agent. Thorough and extensive testing has not identified the potential causative agent, nor the factors that predispose some black rhinoceros to developing IHVS. Further research into the rhinoceros immune system is ongoing and should help elucidate the mechanisms through which IHVS develops.

Presumptive dirofilariasis in a pale-headed saki monkey (Pithecia pithecia)

A 6-yr-old male pale-headed saki monkey (Pithecia pithecia), born at the Dallas Zoo, reentered the collection in 1994 after it was housed for 4 yr in Rhode Island and 2 yr in Florida. The monkey tested negative for both Dirofilaria immitis microfilariae and D. immitis adult antigens (via commercially available tests) upon return. However, it tested positive for adult antigens 1 yr later, and additional testing, including ultrasonography, suggested a diagnosis of aberrant dirofilariasis. Relevant evidence of previous microfilaremia in pale-headed saki monkeys at the Dallas Zoo is reviewed. Dirofilaria immitis infection should be included in the differential diagnosis list for any nonhuman primate with cardiopulmonary disease wherever the parasite is enzootic.

Itraconazole plasma and tissue concentrations in the spiny lizard (Sceloporus sp.) following once-daily dosing

Mycotic infections in reptiles present as primary diseases and as secondary problems in healing wounds and immunocompromised animals. A triazole antimycotic drug, itraconazole is orally active and well distributed and is effective against many common fungal pathogens in humans. To assess plasma and tissues concentrations after oral dosing in reptiles, a 23.5-mg/kg (mean) itraconazole dose was administered orally with a standard food bolus once daily for 3 days to 10 groups of three or four spiny lizards (Sceloporus sp.). On days 0, 1, 2, 3, 4, 6, 9, 12, and 18, group samples of blood, liver, and muscle were collected. Microbiologic assay of itraconazole concentrations was performed on these pooled samples. Values from an elimination graph of the concentrations of area under the curve (377.21 micrograms.hr/ml) and terminal elimination half-life (48.3 hr) were obtained for itraconazole in spiny lizard plasma. Peak itraconazole concentration of 2.48 micrograms/ml was obtained in two half-lives and would be expected to achieve steady state at approximately 3.1 micrograms/ml plasma concentration in 10 days. Peak liver concentration of 4.27 micrograms/ml was attained in 89.95 hr. Muscle concentration did not exceed 0.63 micrograms/ml and declined by 97.3 hr. With this dosing regimen, itraconazole plasma and liver concentrations would persist within reported minimum inhibitory concentrations for many fungal pathogens for 6 days beyond the peak concentration.

Pharmacokinetics of a single intravenous enrofloxacin dose in scimitar-horned oryx (Oryx dammah)

Based on a 1.3 mg/kg mean dosage determined by metabolic energy scaling, enrofloxacin pharmacokinetics of a single i.v. dose of enrofloxacin in five adult scimitar-horned oryx (Oryx dammah) were determined. Drug concentration versus time curves were best fit by residual analysis to a one-compartment open model with a maximum (mean +/- SD) serum concentration after distribution of 1.887 +/- 0.632 micrograms/ml and an elimination half-life of 41.2 +/- 27.5 min. Model-independent parameters were area under the curve (173.63 +/- 147.5 micrograms.min/ml), mean volume of distribution (steady state) (0.80 +/- 0.30 L/kg), clearance (12.07 +/- 7.12 ml/min/kg), and residence time (77.22 +/- 72.8 min). Mean serum enrofloxacin concentrations reached the recommended minimum inhibitory concentration (1.0 micrograms/ml). Drug concentrations remained above the minimum inhibitory concentration of most sensitive bacteria (0.5 micrograms/ml) consistently for 90 min. Based on this study, enrofloxacin would have to be administered parenterally to scimitar-horned oryx at 1.6 mg/kg every 6-8 hr (minimally) to maintain appropriate serum concentrations against susceptible bacteria. The metabolic energy scaled dosed regiment from this study appeared to be too low for the oryx.