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Background Koalas are infected with the koala retrovirus (KoRV) that exists as exogenous or endogenous viruses. KoRV is genetically diverse with co-infection with up to ten envelope subtypes (A-J) possible; KoRV-A is the prototype endogenous form. KoRV-B, first found in a small number of koalas with an increased leukemia prevalence at one US zoo, has been associated with other cancers and increased chlamydial disease. To better understand the molecular epidemiology of KoRV variants and the effect of increased viral loads (VLs) on transmissibility and pathogenicity we developed subtype-specific quantitative PCR (qPCR) assays and tested blood and tissue samples from koalas at US zoos (n = 78), two Australian zoos (n = 27) and wild-caught (n = 21) in Australia. We analyzed PCR results with available clinical, demographic, and pedigree data. Results All koalas were KoRV-A-infected. A small number of koalas (10.3%) at one US zoo were also infected with non-A subtypes, while a higher non-A subtype prevalence (59.3%) was found in koalas at Australian zoos. Wild koalas from one location were only infected with KoRV-A. We observed a significant association of infection and plasma VLs of non-A subtypes in koalas that died of leukemia/lymphoma and other neoplasias and report cancer diagnoses in KoRV-A-positive animals. Infection and VLs of non-A subtypes was not associated with age or sex. Transmission of non-A subtypes occurred from dam-to-offspring and likely following adult-to-adult contact, but associations with contact type were not evaluated. Brief antiretroviral treatment of one leukemic koala infected with high plasma levels of KoRV-A, -B, and -F did not affect VL or disease progression. Conclusions Our results show a significant association of non-A KoRV infection and plasma VLs with leukemia and other cancers. Although we confirm dam-to-offspring transmission of these variants, we also show other routes are possible. Our validated qPCR assays will be useful to further understand KoRV epidemiology and its zoonotic transmission potential for humans exposed to koalas because KoRV can infect human cells.

To determine the diagnostic value of fecal bacterial enteric pathogen cultures (FBEPC) as part of routine preventive medicine protocols in terrestrial mammals housed in a zoological collection, this study investigated the clinical utility of FBEPC results in context of subsequent clinical actions and how its use was rationalized after adjunct use of fecal cytology as a first-line diagnostic tool. Retrospective results (n = 692) that included a routine FBEPC panel of a commercial diagnostic laboratory, including Aeromonas, Salmonella, Campylobacter, Plesiomonas, Shigella, Yersinia, and Edwardsiella, of 417 mammals were organized into preventive (P; n = 485), diagnostic (D; n = 177), or recheck (R; n = 30) samples; for P and D samples, findings were assigned a "clinical significance factor" of 1 to 5 according to culture results and subsequent clinical actions. A score of 3 or higher indicated positive growth of potentially pathogenic bacterial organisms, of which there were 50 FBEPC (P n = 27, D n = 20, R n = 3). The difference in mean clinical significance factor for P versus D samples was significant. Aeromonas spp. were most frequently isolated (n = 32), followed by Salmonella spp. (n = 8) and Plesiomonas shigelloides (n = 8), then Campylobacter spp. (n = 5). There was no growth of Yersinia enterocolitica, Shigella spp., or Edwardsiella spp. In the absence of clinical evidence of gastrointestinal disease, treatment was initiated in only two cases with isolated Campylobacter spp. Implementation of fecal cytology as an initial step in fecal evaluation resulted in a prompt, substantial reduction in number of ordered FBEPC (mean n = 12/month before and n = 5/month after implementation). The findings in this study suggest that FBEPC for these bacterial species has limited value as a screening tool in preventive medicine protocols for the mammalian orders best represented in this study. The use of fecal cytology led to a more targeted and cost-effective use of FBEPC. Fecal cytology as an initial step in preventative and diagnostic testing protocols is recommended.

Beginning 01 January 2016, for all animals transferred into the collection, Disney's Animal Kingdom used a risk-based process that relies on pathogen hazard identification and then assessment and mitigation of the risk for each identified pathogen hazard. Data on morbidity, mortality, and disease introduction was compared for birds transferred in pre– and post–risk-based processes used during the period 2013–2018. When assessing morbidity within 3 mo of acquisition, logistic regression revealed that birds entering “straight to collection” had lower morbidity rates than those entering with either “standard quarantine” or “risk-based standard quarantine” methods (P = 0.032). Mortality within 3 mo of acquisition was not significantly different between straight-to-collection and standard quarantine or risk-based standard quarantine methods (P = 0.40). In addition, no transmissible pathogens of concern were introduced with acquired birds using either method. Implementation of a risk-based approach to animal transfers between zoos and aquariums may be an alternative method that does not pose a greater risk to animal morbidity or mortality while still protecting the collection from disease introduction.

Wildlife health assessments at remote sites may lead to delayed testing of whole blood for complete blood counts (CBC) resulting in artifacts affecting clinical interpretation. Streck Cell Preservative (SCP) is a proprietary liquid stabilization reagent designed to preserve human leukocytes and may be applicable to wildlife health assessments when immediate processing of blood is not possible. The purpose of this study was to determine if SCP adequately preserved EDTA-anticoagulated whole blood from koalas ( Phascolarctos cinereus) for up to 14 days. Blood from 12 captive adult koalas was collected and combined with SCP in a 1 : 1 ratio and refrigerated. Paired samples of SCP treated and untreated blood had CBCs performed at five time-points over 14 days. Streck Cell Preservative extended koala EDTA-anticoagulated whole blood viability to 14 days by decreasing cellular lysis. Species- and method-specific reference intervals for SCP should be generated to avoid clinical misinterpretation, especially when evaluating anemia.

A 3-year-old female Bruce's green pigeon (

The preshipment examination, with associated transmissible disease testing, has become standard practice in the movement of animals between zoos. An alternative disease risk-based approach, based on a comprehensive surveillance program including necropsy and preventive medicine examination testing and data, has been in practice since 2006 between the San Diego Zoo and San Diego Zoo Safari Park. A retrospective analysis, evaluating comprehensive necropsy data and preshipment testing over a 5-yr study period, was performed to determine the viability of this model for use with sending animals to other institutions. Animals (607 birds, 704 reptiles and amphibians, and 341 mammals) were shipped to 116 Association of Zoos and Aquariums (AZA)-accredited and 29 non-AZA-accredited institutions. The evaluation showed no evidence of the specific transmissible diseases tested for during the preshipment exam being present within the San Diego Zoo collection. We suggest that a risk-based animal and institution-specific approach to transmissible disease preshipment testing is more cost effective and is in the better interest of animal welfare than the current industry standard of dogmatic preshipment testing.

Habitat loss and fragmentation threaten the survival of koalas in Queensland. In rural landscapes, remaining koala habitat is often in the form of scattered paddock trees, patches of vegetation and roadside vegetation. The aims of this study were to (1) quantify the use of these three habitat types; (2) determine whether there is an increased use of scattered trees during the breeding season; and (3) describe the movement characteristics (daily step-length and turning angle) of koalas in different habitat types. To do this, koalas were caught and fitted with global positioning system (GPS) loggers that recorded their daily locations. We found koalas utilised all three habitat types in both breeding and non-breeding seasons, but roadside vegetation and scattered trees were utilised significantly more than expected based on their availability within the landscape. We found no significant difference in step-length or turning angles in scattered trees compared with patches of vegetation. We conclude that scattered trees are a critical element of habitat in this rural landscape. This work provides evidence that retaining or planting scattered trees within the rural landscape would likely complement or possibly enhance the conservation value of rural landscapes for koalas.

As modern zoos evolved from menageries, quarantine practices were developed to protect animal collections from the introduction of diseases that might arrive with new animals from wild populations and, more recently, from other managed populations. As the understanding of, and ability to diagnose, diseases grew tremendously in recent decades, quarantine protocols became more stringent and standardized as the tolerance for disease introduction decreased. These practices resulted in healthier animal collections, and the introduction of transmissible pathogens of concern became rarer. Sustainable population management in zoos has further lessened the reliance on taking animals from the wild, and the knowledge of disease risk in such situations has deepened. Today animals being transferred between modern zoological institutions have well-documented medical histories complemented with robust collection health histories. This improved understanding has reduced concerns about disease transmission in many cases. Consequently, more formal use of risk analysis to drive transfer-related examination, diagnostic testing, and quarantine decision making was adopted by a number of zoos and aquariums that have modified their quarantine practices and use risk analysis to reduce quarantine requirements, in some cases moving animals directly into collections after transportation. This commentary discusses the rationale for and changes to quarantine processes for animal acquisitions in zoos and aquariums, using risk analysis to direct decision making.

An 11-year-old female sugar glider (Petaurus breviceps) was presented with a rapidly growing dermal mass at the lateral margin of the right patagium. The result of a biopsy was consistent with a dermal hemangiosarcoma, and findings of histopathologic examination of the abnormal tissue confirmed the tentative diagnosis following surgical excision of the mass. At 1 year postsurgery, there was no evidence of local recurrence or metastatic disease. There are published reports of sugar gliders diagnosed with neoplasia, and oncology cases affecting this species are occasionally seen in clinical practice. Based on an extensive literature search, the authors believe this is the first report of a dermal hemangiosarcoma in a sugar glider.

The recent classification as threatened status of the northern koala (Phascolarctos cinereus) by the Australian Government highlights the importance of the conservation and health management of this iconic Australian marsupial. This case series describes gastrointestinal torsion and intussusception in six northern koalas (three males, three females, 2-11 yr old) at the San Diego Zoo from 1976 to 2012. Two koalas died shortly after presentation. Diagnoses of ileocecal intussusception, resulting from enteritis in one case and cecal torsion in the other, were made at postmortem examination. One koala died 4 days after an exploratory laparotomy, with negative findings, and an acute double colonic intussusception was diagnosed at postmortem examination. Two small intestinal mesenteric torsion and one proximal colon mesenteric torsion cases were successfully corrected surgically. In the case of colonic mesenteric torsion, the koala had recurrent clinical signs 2 wk later, and a second surgery requiring resection and anastomosis of ischemic jejunum was performed, with the koala dying shortly afterward. One koala with small intestinal torsion had a recurrence of torsion 22 mo later and subsequently died. The koala with the second case of small intestinal torsion remains alive 14 mo postsurgical correction. All six koalas presented with signs of colic that included anorexia, lethargy, depression, acute abdominal distension, abdominal stretching, decreased fecal output, open-mouth gasping, or a combination of symptoms. Abdominal radiographs may show stacked gastrointestinal linear gas patterns and contrast stasis. Prevalence of torsion and intussusception is low at this institution (2%), although recurrence in individuals is common (50%) and overall survival is poor (83%), which emphasizes the importance of timely recognition, surgical correction, and postoperative management. While inciting etiologies were unable to be determined in these cases, monitoring generalized gastrointestinal health and differing Eucalyptus sp. effects on individual koala's gastrointestinal function, parasite control, and stress minimization through standardized husbandry practices are likely important.

As part of a health investigation on koalas at San Diego Zoo, serum samples were analyzed from 18 free-ranging and 22 zoo-based koalas, Phascolarctos cinereus. Serum concentrations of calcium, chloride, cobalt, copper, iron, magnesium, manganese, molybdenum, phosphorus, potassium, selenium, sodium, zinc, and vitamins A, E, and 25(OH)D3 were quantified. Calcium, chloride, molybdenum, selenium, and vitamin E concentrations were significantly higher in zoo-based koalas than in free-ranging koalas, whereas magnesium, manganese, phosphorus, and zinc concentrations were significantly higher in the free-ranging koalas. No significant differences were found between genders. The results from this study will help to establish a starting point for determining target circulating nutrient concentrations in koalas.

A 3-year-old female Bruce's green pigeon (Treron waalia) was presented with granulomatous inflammation of the cere and underlying tissues with osteomyelitis and bone proliferation of the dorsal premaxilla. Biopsy and culture revealed the presence of Mycobacterium avium-intracellulare complex, and multi-antimicrobial treatment was initiated with clarithromycin, ethambutol, rifabutin, and enrofloxacin. The cere lesion improved and no evidence of systemic granulomas was observed over 4 months of treatment, although leukocytosis and monocytosis persisted. Five months after discontinuation of antibiotic therapy, the white blood cell count had normalized, but distal beak irregularities and partial recurrence of the mass were present. The bird died 15 months after discontinuation of antibiotic therapy and necropsy revealed no evidence of active mycobacteriosis of the beak or cere. This report documents an unusual clinical presentation of mycobacteriosis, in addition to its successful resolution.

Due to climatic conditions in Northern America and Europe, koalas (Phascolarctos cinereus) are often housed indoors. Koala joeys raised in these environments are susceptible to the development of metabolic bone disease due to a lack of exposure to solar ultraviolet radiation to themselves and their dam. As an initial step toward describing vitamin D sufficiency and adequately measuring responses to supplementation, vitamin D values were calculated by using serum collected from 20 free-ranging koalas on St. Bees Island, Queensland, Australia. Vitamin D values ranged from 8.1 to 30.4 pg/ml (18.4 +/- 5.5 pg/ml) for 1, 25-hydroxyvitamin D, and from 1 to 14 nM/L (7.4 +/- 3.0 nM/L) for 25-hydroxyvitamin D. These koala serum vitamin D values are unusually low when compared with eutherian mammals. Although this study was limited in numbers and in the geographically range of the koalas sampled, it does suggest that the koala's requirement for vitamin D is low. Therefore, supplementation to prevent disease may be relatively easy to achieve because low doses will likely meet requirements. Caution should be taken to avoid intoxication if supplementing vitamin D in koalas.

Koala retrovirus (KoRV) is a gammaretrovirus that has been identified in both captive and free-ranging koalas ( Phascolarctos cinereus ) with variable geographic distribution in Australia. KoRV is capable of both exogenous and endogenous transmission, which provides an interesting research platform for scientists to study active retrovirus endogenization into a host genome and offers veterinary scientists an opportunity to examine the clinical consequences of KoRV infection in koalas. Causation between KoRV and frequently recognized clinical conditions associated with immune suppression and neoplasia in koalas has not been definitively established, however research continues to evaluate a potential association. Three KoRV variants, KoRV-A, KoRV-B, and KoRV-J, have been the most thoroughly described and preliminary evidence suggests KoRV variability may be fundamental in host pathogenicity. In addition to reviewing what is currently known about KoRV, this article discusses treatment, management, and future research directions.

Quarantine is designed primarily to prevent the introduction of transmissible diseases to zoological collections. Improvements in preventive medicine, disease eradication, and comprehensive pathology programs call into question current industry quarantine standards. Disease risk analysis was used at the San Diego Zoo (SDZ) and the SDZ Safari Park to eliminate quarantine isolation and transmissible disease testing for animals transferred between the two institutions. To determine if a risk-based approach might be valid between other institutions and SDZ, we reviewed quarantine data for animals arriving at SDZ from 81 Association of Zoos and Aquariums (AZA)-accredited and 124 other sources (e.g., non-AZA-accredited institutions, private breeders, private dealers, governmental bodies) over a 5-yr period (2009-2013). No mammal or herptile failed quarantine due to transmissible diseases of concern. Approximately 2.5% of incoming birds failed quarantine due to transmissible disease; however, all 14 failed individuals were obtained from three nonaccredited sources (private breeders, confiscation). The results of our study suggest that a risk-based approach could be used to minimize or eliminate quarantine for the transfer of animals from institutions with comprehensive disease surveillance programs and/or preshipment testing practices. Quarantine isolation with testing remains an essential defense against introducing transmissible diseases of concern when there is a lack of health knowledge about the animals being received.

In a clinical setting, especially with species of special interest, it is important to use all clinical pathology testing options for general health monitoring and diagnosis. Protein electrophoresis (EPH) has previously been shown to be an important adjunct tool in veterinary medicine. Serum samples from 18 free-ranging and 12 zoo-based koalas (Phascolarctos cinereus) were subject to EPH analysis. Significant differences were found between the two groups for the following values: total protein, albumin, beta globulins, and albumin-globulin ratio (P0.05). By using the combined data, the minimum-maximum values for the EPH fractions were as follows: total protein 5.0-7.8 g/dl, albumin 2.8-4.7 g/dl, alpha-1 globulins 0.5-1.1 g/dl, alpha-2 globulins 0.3-0.7 g/dl, beta globulins 0.4-1.0 g/dl, gamma globulins 0.2-1.0 g/dl, and albumin-globulin ratio 1.0-2.1.

The objective of this study is to describe computed tomography (CT) and magnetic resonance (MR) for the cross-sectional imaging of the normal anatomy of the nasal cavity and paranasal sinuses of the koala (Phascolarctos cinereus), to provide reference figures for gross anatomy with corresponding CT and MR images and to compare the features of the nasal cavity and paranasal sinuses of the normal koala with that reported in other domestic species. Advanced imaging can be used to aid in diagnosis, to plan surgical intervention, and to monitor therapeutic responses to diseases of the nasal passages in koalas. One clinically normal koala was anesthetized twice for the separate acquisition of dorsal CT scan images and transverse, dorsal, and sagittal MR images of its nasal cavity and paranasal sinuses. Sagittal and transverse CT planes were reformatted. Three fresh koala skulls were also transected in one of each transverse, sagittal, and dorsal planes and photographed. The CT and MR images obtained were matched with corresponding gross anatomic images and the normal bone, tissues and airway passages were identified. All anatomic structures were readily identifiable on CT, magnetic resonance imaging (MRI), and gross images. CT and MRI are both valuable diagnostic tools for imaging the nasal cavities and paranasal sinuses of koalas. Images obtained from this project can be used as baseline references for future comparison with diseased koalas to help with diagnosis, surgical intervention, and response to therapy.

Despite being a charismatic and well-known species, the social system of the koala (Phascolarctos cinereus - the only extant member of the family Phascolarctidae) is poorly known and much of the koala's sociality and mating behaviors remain un-quantified. We evaluated these using proximity logging-GPS enabled tracking collars on wild koalas and discuss their implications for the mating system of this species. The frequency and duration of malefemale encounters increased during the breeding season, with male-male encounters quite uncommon, suggesting little direct mating competition. By comparison, female-female interactions were very common across both seasons. Body mass of males was not correlated with their interactions with females during the breeding season, although male size is associated with a variety of acoustic parameters indicating individuality. We hypothesise that vocal advertising reduces the likelihood of male-male encounters in the breeding season while increasing the rate of male-female encounters. We suggest that male mating-season bellows function to reduce physical confrontations with other males allowing them to space themselves apart, while, at the same time, attracting females. We conclude that indirect male-male competition, female mate choice, and possibly female competition, mediate sexual selection in koalas.

Standing sedation was provided for 14 clinical procedures in three African elephants (Loxodonta africana) managed by combined protected and modified-protected contact and trained through operant conditioning. An initial hand-injection of detomidine hydrochloride and butorphanol tartrate at a ratio of 1:1 on a microg:microg basis was administered intramuscularly, with a dosage range of 50-70 mg (12.9-19.7 microg/kg) for each drug. The initial injection resulted in adequate sedation for initiation and completion of eight procedures, whereas supplemental doses were required for the remaining procedures. The dosage range for the supplemental injections of each drug was 4.0-7.3 microg/kg. Initial effect was noted within 3.0-25 min (mean = 11.6 min, SD +/- 5.9 min), with maximal effect occurring at 25-30 min for those procedures not requiring supplementation. In all but one procedure, this effect was maintained until the end of the procedure, which ranged from 47 to 98 min (mean = 74.7 min, SD +/- 18.8 min). No cardiac or respiratory depression was appreciated. Recovery after administration of reversal agents was rapid and complete, ranging from 2 to 20 min (mean = 9.0 min, SD +/- 7.0 min). On the basis of the authors' experience, recommended dosage ranges for reversal agents would be intravenous yohimbine (73.4-98.5 microg/kg), intravenous naltrexone (48.9-98.5 microg/kg), and intramuscular naltrexone (73.4-98.5 microg/kg). Approximately one-third to one-half of the total naltrexone dose should be administered intravenously. Mild adverse side effects limited to the gastrointestinal tract were observed in association with five procedures including abdominal distention with or without transient anorexia. Administration of reversal agents, encouraging exercise and water consumption, and administration of flunixin meglumine were helpful in the resolution of signs. In addition to gastrointestinal signs, slight ataxia was observed before initiation of surgical stimulation during one procedure in which 19.7 microg/kg of each drug was administered. On the basis of the procedures that did not require supplementation to initiate treatment and taking into consideration the potential for ataxia at higher doses, a starting dosage range of 14.7-16.2 microg/kg of both detomidine and butorphanol in a ratio of 1:1 on a microg:microg basis administered i.m. simultaneously is recommended.

Three koalas (Phascolarctos cinereus) presented with moderate to severe interproximal space accumulation with Eucalyptus spp. at the San Diego Zoo. Premise™ trimodal composite was used to create dental onlay bridge-like prostheses to eliminate open, enlarged interproximal spaces. The prostheses prevented further leaf material accumulation within the interproximal spaces and consequently reduced periodontal disease. Aesthetically, the prosthesis replicates normal tooth coloration and appearance and wears at a similar rate to surrounding teeth. Prosthetic repair or replacement may be required, so periodic examination every 3–6 mo is recommended.

A 42-year-old female Indian elephant (Elephas maximus indicus) developed a sudden onset of excessive salivation and dysphagia. Esophageal obstruction was suspected; possibly related to palm frond ingestion. Esophageal endoscopy revealed a mat of plant material in the distal esophagus. An initial attempt at relieving the obstruction was unsuccessful, but subsequent use of custom-made instruments along with insufflation and hydropulsion enabled partial removal of the material. Postimmobilization care included aggressive intravenous and rectal fluids, anti-inflammatory and antibiotic administration, and fasting. Despite treatment, the dysphagia persisted and the elephant was euthanized due to lack of improvement and grave prognosis. Postmortem examination revealed remaining plant material in the esophagus, complicated by an esophageal dissection, mural hematoma, and secondary bacterial infection. Iatrogenic trauma may have contributed to the extent of esophageal injury. Although treatment was ultimately unsuccessful, the supportive care employed could potentially aid recovery in cases of less severe esophageal trauma.

Female cockatiels (Nymphicus hollandicus) are prone to development of reproductive problems, especially overproduction of eggs and egg binding. Salpingohysterectomy is recommended for permanent control of these problems because removal of the oviduct and uterus seems to suppress ovulation. Salpingohysterectomy has not been used commonly as a preventative measure, in part because of concerns about surgical risk, especially with traditional surgical methods. In addition, clients may not perceive its value. In this study, endoscopic salpingohysterectomy was evaluated in 14 juvenile female cockatiels. Hemorrhage was negligible and all 14 procedures were successful. The positive outcomes suggest that the procedure is safe and simple when performed by veterinarians familiar with avian coelomic endoscopic techniques. Endoscopic salpingohysterectomy in juvenile cockatiels could be used to prevent future reproductive problems. Further study is required to evaluate long-term effects and the preventative va...

An outbreak of mycoplasmosis caused by Mycoplasma alligatoris resulted in the death or euthanasia of 60 American alligators (Alligator mississippiensis) from a population of 74 captive bull alligators in Florida in 1995. The natural reservoir, routes of transmission, and host range of M. alligatoris are unknown. This study was undertaken to determine whether crocodilian species other than American alligators are susceptible to M. alligatoris. Six broad-nosed caimans (Caiman latirostris) and six Siamese crocodiles (Crocodylus siamensis) were experimentally inoculated with 106 colony forming units (CFU) of M. alligatoris instilled through the glottis. Two caimans and two crocodiles were used as negative controls. Six and four American alligators were used as positive and negative controls, respectively. Three of six (50%) inoculated caimans died within 10 wk postinoculation (PI) of severe mycoplasmosis. Gross necropsy, histopathologic, and culture results were similar for broad-nosed caimans and Am...

This article covers the manual restraint and anesthesia of marsupials, insectivores, and chiroptera. Marsupials commonly kept as pets in the U.S. [e.g., eastern gray kangaroos ( Macropus giganteus ), Bennett's wallabies ( Macropus rufogriseus ), and sugar gliders ( Petamus breviceps )] are covered in detail. Marsupial species kept in zoological parks [e.g., Tasmanian devils, koalas ( Phascolarctos cinereus ), and common wombats ( Vombatus ursinus )] are covered in less detail. Of the insectivores, only the African hedgehog ( Atelerix albiventris ) and the European hedgehog ( Erinaceus europaeus ) are commonly kept as pets and, consequently, the insectivore section concentrates on discussing these two species. The section on chiropteran anesthesia is divided into two broad categories: the megachiropterans (flying foxes and fruit bats) and the microchiropterans (insectivorous bats). Most of the information on the species covered in this article is anecdotal, and this should be kept in mind when using the anesthesia protocols described.

During a preventive medicine examination on a 13-yr-old intact female African spot-necked otter (Lutra maculicollis), radiographs were obtained and a cranial thoracic mass was noted. Cytology from an ultrasound-guided fine-needle aspirate was suggestive of a thymoma. Surgical removal was performed and this diagnosis was confirmed by histopathology. At a recheck examination 6 mo postsurgery, there was no evidence of recurrence. This case highlights the value of a comprehensive preventive medicine program that resulted in the early detection of a subclinical thymoma and its successful removal.

Ten psittacine birds (3 African grey parrots [Psittacus erithacus], 3 blue and gold macaws [Ara ararauna], 2 scarlet macaws [Ara macao], a harlequin macaw [Ara ararauna × macao], and a yellow-naped Amazon parrot [Amazona ochrocephala auropalliata]) with histories of chronic sinusitis were referred for evaluation before possible surgical therapy. The duration of clinical signs in these birds ranged from 8 months to 11 years, and response to conventional medical therapy had been poor. Diagnostic procedures performed in each bird included a physical examination, complete blood count, plasma biochemical analysis, survey whole body and skull radiographs, and skull magnetic resonance imaging. In 7 of the 10 birds, a discrete lesion was localized by using magnetic resonance imaging. Six of these 7 birds had surgery performed to remove the lesion. Four granulomas, a mucocele, and a polyp were diagnosed by histopathologic examination. The chronic sinusitis resolved after surgery in 5 birds. Magnetic reson...

A 13-yr-old ring-tailed lemur (Lemur catta) was evaluated for depression, anorexia, polyuria, and polydipsia. The lemur was in poor body condition and was anemic, hypoalbuminemic, and hyponatremic. Cytologic examination of aspirates of the spleen, liver, and bone marrow and histopathologic examination of liver and bone marrow biopsies revealed a disseminated round cell tumor. After euthanasia, necropsy revealed hepatomegaly, splenomegaly, and mesenteric lymphadenomegaly. Neoplastic cells were present within the spleen, liver, kidneys, multiple lymph nodes, bone marrow, lung, small intestine, pancreas, and testicle and were composed of large anaplastic round cells in a background of small well-differentiated lymphocytes. Immunohistochemical analysis revealed that the small well-differentiated lymphocytes labeled for the anti-human T-cell marker, CD3, and the large anaplastic round cells labeled with the anti-human B-cell marker, CD79a. On the basis of the immunohistochemical staining results and morphologic appearance, a diagnosis of a T-cell-rich B-cell lymphoma was made.

A castrated adult male 1.0-kg domestic ferret (Mustela putorius furo) was referred for evaluation of a mass of >5 mo duration that was associated with the thoracic spine. The ferret had motor dysfunction and no conscious proprioception or pain perception in either hind limb. Segmental reflexes were present. Survey radiography, myelography, and magnetic resonance imaging showed a mass involving the ninth and 10 thoracic vertebrae and compressing the spinal cord. Decompressive surgery was performed, but clinical signs persisted. A diagnosis of chordoma was made using histopathology and immunohistochemistry. This is the first reported case of a chordoma involving the thoracic vertebrae in a domestic ferret.

A wild-caught gopher tortoise, Gopherus polyphemus, was examined on three occasions for evaluation and treatment of subcutaneous masses. Following histopathologic examination and microbiologic culture of the masses, a diagnosis of Serratia marcescens abscesses was made. Despite surgical excision of the abscesses followed by two courses of treatment with ceftazidime (20 mg/kg q 72 h for 2 wk) given two months apart, further abscess formation occurred. While radiography failed to reveal any internal masses, magnetic resonance imaging revealed masses within the lung parenchyma. The tortoise was euthanatized, necropsy revealed multiple abscesses in the liver, kidney, and lung. Magnetic resonance imaging was found to be a useful diagnostic tool in a case where abscesses within the coelom were suspected.

Due to climate restrictions in parts of North America and Europe, koalas (Phascolarctos cinereus) are housed indoors. Koala young (joeys) raised indoors are susceptible to the development of metabolic bone disease (MBD) due to a lack of exposure to natural ultraviolet light to themselves and their female parents (dams). In this retrospective study, radiographs from 27 koala joeys born at four zoos in North America and two zoos in Europe were evaluated for signs of MBD. Eight of the joeys were radiographically diagnosed with MBD and four additional joeys were considered suspect MBD cases; in two joeys absence or presence of MBD could not be determined. All joeys had mild to severe hip and shoulder dysplasia. There were significant associations between a lack of exposure to UV light and MBD development and between MBD and the degree of severity of hip and shoulder dysplasia. It is recommended to house breeding female koalas and their joeys outdoors whenever possible.

Leukemia and lymphoma account for more than 60% of deaths in captive koalas ( Phascolarctos cinereus ) in northeastern Australia. Although the endogenizing gammaretrovirus koala endogenous retrovirus (KoRV) was isolated from these koalas, KoRV has not been definitively associated with leukemogenesis. We performed KoRV screening in koalas from the San Diego Zoo, maintained for more than 45 y with very limited outbreeding, and the Los Angeles Zoo, maintained by continuously assimilating captive-born Australian koalas. San Diego Zoo koalas are currently free of malignant neoplasias and were infected with only endogenous KoRV, which we now term subtype “KoRV-A,” whereas Los Angeles Zoo koalas with lymphomas/leukemias are infected in addition to KoRV-A by a unique KoRV we term subtype “KoRV-B.” KoRV-B is most divergent in the envelope protein and uses a host receptor distinct from KoRV-A. KoRV-B also has duplicated enhancer regions in the LTR associated with increased pathology in gammaretroviruses. Whereas KoRV-A uses the sodium-dependent phosphate transporter 1 (PiT1) as a receptor, KoRV-B employs a different receptor, the thiamine transporter 1 (THTR1), to infect cells. KoRV-B is transmitted from dam to offspring through de novo infection, rather than via genetic inheritance like KoRV-A. Detection of KoRV-B in native Australian koalas should provide a history, and a mode for remediation, of leukemia/lymphoma currently endemic in this population.

Nasal masses in the koala (Phascolarctos cinereus) are not uncommon and can be challenging to diagnose and treat. Differential diagnoses for nasal masses in the koala are cryptococcal granulomas, nasal polyps, nasal adenocarcinoma, and osteochondromatosis. This report describes successful surgical approaches for two adult koalas with nasal masses and includes photodocumentation and description of the anatomy of the koala nasal passages from the postmortem transverse sectioning of a normal koala head. Surgical removal of the nasal masses in these koalas resulted in a rapid resolution of clinical signs.

At the San Diego Zoo (California, USA), 22 cases of megaesophagus were diagnosed in the parma wallaby (Macropus parma), yielding a prevalence of 21.1%. Parma wallabies often have no clinical signs until severe and chronic dilation of the esophagus is present. Clinical signs of advanced disease include weight loss, swelling of the cervical region, regurgitation without reswallowing of ingesta, short flight distance, depression, collapse, dyspnea, and sudden death. Retrospective and prospective studies at the San Diego Zoo and a multi-institutional survey in the United States were used to try to determine the cause of megaesophagus. The retrospective study did not identify an etiology. The prospective study revealed megaesophagus and severely delayed esophageal transit time in eight of eight animals. Myasthenia gravis, lead toxicosis, toxoplasmosis, and thyroid disease were eliminated as possible causes. Of 286 living and dead parma wallabies surveyed at other institutions, three cases of esophageal diverticulum and one case of megaesophagus were reported. The cause of megaesophagus in parma wallabies was not determined.

Koala retrovirus (KoRV)-related disease is a major suspected cause of death in koalas (Phascolarctos cinereus) in zoos in North America. There are currently eleven zoos exhibiting koalas in North America. A mortality survey of these institutions indicated that mortalities directly related to KoRV (e.g., lymphoma, leukemia, anemia, bone marrow hypoplasia, osteochondromatosis) and mortalities suspected to be KoRV-related (e.g., immunosuppression, unusual opportunistic infections (e.g., Coccidioidomycosis), potentially other neoplasia) account for 41% of deaths. Testing of the living North American koala population for a recently reported, exogenous koala retrovirus variant (KoRV-B) identified four KoRV-B-positive individuals in a population of 54 koalas (7.4%).

A 46-yr-old female Sumatran orangutan (Pongo abelli) was first diagnosed with pericardial effusion in July 2006. Pericardiocentesis performed in January 2007 only provided short-term relief. In May 2007, a pericardial-peritoneal window was created using a transabdominal subxiphoid pericardiostomy technique, providing immediate and long-term relief. Seven months later, the orangutan was euthanized due to worsening heart failure, and no pericardial effusion was present. Transabdominal subxiphoid pericardiostomy offers a straightforward surgical approach that can provide significant relief in cases of chronic pericardial effusion in great apes.

A retrospective/prospective radiographic study documented 55 cases of moderate to severe hip dysplasia, with varying degrees of shallowing of the acetabulum, flattening or loss of the femoral head, widening or loss of the femoral neck, and femoral diaphyseal abnormalities in northern koalas (Phascolarctos cinereus) in the San Diego Zoo (San Diego, California, USA) collection. For the retrospective study, historic radiographs were examined when availble. For the prospective study, three standard views (ventrodorsal extended leg, ventrodorsal frog leg, and lateral extended leg) were used. A scoring system was developed using four areas (acetabulum, femoral head, femoral neck, and femur) and ranges of 0 to 5 (0 = not affected to 5 = severely affected) for each area, creating a total score out of 40. Scores were graded as follows: 0-2 = normal dysplasia; 3-6 = mild dysplasia; 10-19 = moderate dysplasia; and 20-40 = severe dysplasia. Thirty koalas were graded as severe, 25 koalas as moderate, and 38 koalas as excellent or mild. Affected koalas may or may not demonstrate gait abnormalities. Mild to severe degenerative joint disease may develop and symptoms may be alleviated with glucosamine/chondroitin sulfate and nonsteroidal anti-inflammatory drugs. The etiology of hip dysplasia in koalas is not currently understood.

A juvenile ostrich (Struthio camelus) was castrated in 2 procedures (right and left hemicastrations) at 3 and 4 months of age. The bird had 3 episodes of depression, inappetence, and head-shaking with apparent dysphagia of 1-3 days duration during the 4 months after the first surgical procedure. It was found dead at 7.5 months of age with no clinical signs in the days immediately preceding the death. At necropsy, the intestine was found entrapped in the right pulmonary ostium. Death likely resulted from compression of the air sacs and heart by the dilated bowel. Care should be taken to avoid disrupting the air sac wall integrity between the thoracic and abdominal regions of the coelom during the castration of juvenile ostriches.

Mycoplasma alligatoris was the suspected etiology of an epidemic of acute multisystemic inflammatory disease which emerged in captive American alligators (Alligator mississippiensis) in Florida (USA) in 1995. In an experimental inoculation study conducted from April through October 1999, 18 alligators were inoculated with 10(2), 10(4), or 10(6) colony forming units (CFU) of M. alligatoris by instillation into the glottis. As early as 1 wk post-inoculation (PI), mycoplasma were cultured from blood of three of six alligators inoculated with 10(6) CFU. Two of those died and the third was euthanatized within 4 wk PI. Necropsy gross findings included fibrinous polyserositis and polyarthritis. Histopathologic changes in affected individuals included pulmonary edema, interstitial pneumonia, pericarditis, myocarditis, meningitis, and synovitis. Mycoplasma were cultured quantitatively in high numbers from trachea, lung, coelomic cavity, liver, spleen, interior of pericardial sac, heart, blood, brain, and limb joints. In alligators inoculated with 10(6) CFU, heterophilia and moderate hyperglycemia peaked about 4 wk PI, and seroconversion occurred by 6 to 8 wk PI. Necropsy gross and histologic findings were generally unremarkable for the surviving alligators inoculated with 10(6) CFU, alligators inoculated with 10(2) or 10(4) CFU, and four uninoculated control alligators. Mycoplasma were not cultured at any time point from those alligators. The findings confirm that M. alligatoris can cause fulminant inflammatory disease and rapid death of alligators.