Hypertrophic osteopathy in South Australian koalas (Phascolarctos cinereus) with concurrent pulmonary actinomycosis.

Pulmonary actinomycosis is described in 17 South Australian koalas necropsied between 2016 and 2019. From these cases, four koalas had secondary hypertrophic osteopathy. Plain radiographical and computed tomography images demonstrated periosteal reaction on multiple appendicular skeletal bones in all cases, including scapula, humerus, ulna, radius, ilium, femur, tibia, fibula, metacarpus, metatarsus and phalanx. Grossly, periosteal surfaces of the metaphyses and diaphyses of long bones were thickened and roughened; microscopically, this was characterised by bi-layered proliferation of well-differentiated trabecular bony spicules oriented perpendicular to the cortex (pseudocortices) and separated by vascular connective tissue, typical for hypertrophic osteopathy. Well characterised in domestic species and rarely reported in marsupials, this is the first radiographical and pathological characterisation of hypertrophic osteopathy in koalas, associated with pulmonary actinomycosis in all cases.

Pathological Findings in Koala Retrovirus-positive Koalas (Phascolarctos cinereus) from Northern and Southern Australia.

Koala retrovirus (KoRV) infection shows differences in prevalence and load between northern and southern Australian koala populations; however, the effect of this on diseases such as lymphoma and chlamydial disease is unclear. This study compared clinicopathological findings, haematology and splenic lymphoid area of KoRV-positive koalas from northern (Queensland [Qld], n = 67) and southern (South Australia [SA], n = 92) populations in order to provide further insight into KoRV pathogenesis. Blood was collected for routine haematology and for measurement of KoRV proviral load by quantitative polymerase chain reaction (qPCR). Plasma samples were assessed for KoRV viral load by reverse transcriptase qPCR and conjunctival and cloacal swabs were collected for measurement of the load of Chlamydia pecorum (qPCR). During necropsy examination, spleen was collected for lymphoid area analysis. Lymphoma was morphologically similar between the populations and occurred in koalas with the highest KoRV proviral and viral loads. Severe ocular chlamydial disease was observed in both populations, but urinary tract disease was more severe in Qld, despite similar C. pecorum loads. No associations between KoRV and chlamydial disease severity or load were observed, except in SA where viral load correlated positively with chlamydial disease severity. In both populations, proviral and viral loads correlated positively with lymphocyte and metarubricyte counts and correlated negatively with erythrocyte and neutrophil counts. Splenic lymphoid area was correlated positively with viral load. This study has shown further evidence for KoRV-induced oncogenesis and highlighted that lymphocytes and splenic lymphoid tissue may be key sites for KoRV replication. However, KoRV infection appears to be highly complex and continued investigation is required to fully understand its pathogenesis.

Symmetric dimethylarginine values in koalas (Phascolarctos cinereus) based on oxalate nephrosis status.

Oxalate nephrosis is a prevalent renal disease in koalas (Phascolarctos cinereus) of the Mount Lofty Ranges population in South Australia. The symmetric dimethylarginine (SDMA) assay is widely used in companion animals to diagnose renal disease, particularly in the early stages. This study aimed to determine: (1) reference intervals for SDMA in koalas and (2) SDMA values of koalas with oxalate nephrosis. Blood samples were collected from 41 Mount Lofty Ranges koalas euthanased on welfare grounds. Koalas were necropsied and, based on renal histopathology, were classified as unaffected (n = 22) or affected (n = 19) by oxalate nephrosis. Serum or plasma samples were analysed for creatinine, urea and SDMA and urine samples for urine specific gravity (USG). The reference interval for SDMA in unaffected koalas was 2.4-22.9 µg/dL. In koalas with oxalate nephrosis, SDMA was elevated in 74% of cases above the upper limit of the confidence interval. SDMA was elevated in three affected koalas with normal creatinine values. A positive correlation was found between SDMA and creatinine (R = 0.775, P < 0.001) and SDMA and urea (R = 0.580, P < 0.001) and a negative correlation between SDMA and USG (R = -0.495, P = 0.027). In conclusion, SDMA correlates well with other commonly used tests of renal function in koalas and should be included as part of the standard diagnostic process to increase the accuracy of oxalate nephrosis diagnosis in koalas.

Haematological reference intervals of wild southern Australian koalas (Phascolarctos cinereus).

OBJECTIVE: Current haematology reference intervals (RIs) for koalas were developed in northern Australian koalas, using low numbers and/or individuals of unknown Chlamydia pecorum and koala retrovirus (KoRV) status. This study developed haematological RIs for wild, clinically healthy southern Australian koalas of known C. pecorum and KoRV infection status and investigated the effects of population, age and sex. METHODS: Haematological RIs were determined for 138 clinically healthy South Australian koalas (Mount Lofty Ranges [MLR], n = 68; Kangaroo Island, n = 70) examined in April 2016 and February 2017, respectively. C. pecorum and KoRV status were determined by PCR. RESULTS: RIs for southern koala haematological parameters were established for all koalas based on the finding that there were limited differences in haematological values in koalas with subclinical C. pecorum or KoRV infections (P > 0.05), except KoRV-infected koalas had a lower haematocrit than noninfected koalas. MLR koalas had significantly lower erythrocyte mass and leucocyte counts than Kangaroo Island koalas. Young koalas had significantly lower haemoglobin, haematocrit and higher mean cellular haemoglobin concentration and lymphocyte counts than adult koalas. MLR male koalas had elevated erythrocyte, leucocyte and neutrophil counts compared with MLR females. CONCLUSION: The haematological RIs developed in this study are based on a large number of clinically healthy koalas, where subclinical C. pecorum and KoRV infections had no effect on haematological values and will be a valuable tool during clinical examination and disease investigation by veterinarians and researchers Australia-wide.

Placenta Accreta in an Oragnutan (Pongo abelii) and a Chimpanzee (Pan troglodytes).

Placenta accreta is defined as abnormal adherence of the placenta to the uterine wall. Placenta accreta is recognized as a common problem in human medicine, but has apparently not been reported previously in great apes, despite similarity in their reproductive biology. A 36-year-old multiparous female Sumatran orangutan (Pongo abelii) and a 20-year-old nulliparous female chimpanzee (Pan troglodytes), with gross uterine and histological uterine vascular changes that are characteristic of placenta accreta, are presented.

Necropsy findings of koalas from the Mount Lofty Ranges population in South Australia.

OBJECTIVE: This study reports necropsy findings of koalas from the Mount Lofty Ranges region in order to identify health threats to this mainland South Australian population. METHODS: Koalas from the Mount Lofty Ranges region (n = 85) that had died or been euthanased on welfare grounds were examined at necropsy during 2012-13 at the School of Animal and Veterinary Sciences, University of Adelaide. Disease findings, approximate age, sex and body condition of koalas were recorded. Histopathological examination was undertaken on gross lesions and in suspect cases, skin scrapings taken for microscopy and PCR performed for Chlamydia pecorum detection. RESULTS: Traumatic injury was the most common necropsy finding (48/85; 57%), caused by motor vehicle accidents (35/48; 73%), canine attacks (11/48; 23%) or bushfire burns (2/48; 4%). Oxalate nephrosis (27/85; 32%) was also more common than other conditions. Infectious diseases included chlamydiosis (10/85; 12%) and sarcoptic mange (7/85; 8%). Marked testis asymmetry was evident in 11% (6/56) of males, with histopathology suggestive of atrophic change in four animals. Other pathological conditions included gastrointestinal disease (7/85; 8%) and respiratory disease (3/85; 4%). Almost half of the koalas (38/85; 45%) were found to have two or more abnormalities at necropsy. CONCLUSION: This study found trauma, mainly from motor vehicle accidents, and oxalate nephrosis to be the predominant causes of death and/or disease in koalas from the Mount Lofty Ranges region. Recent emergence of both clinical chlamydiosis and sarcoptic mange has also occurred, providing insight into the health status and causes of disease or injury in this South Australian mainland koala population.

Identification of stable reference genes for quantitative PCR in koalas.

To better understand host and immune response to diseases, gene expression studies require identification of reference genes with stable expression for accurate normalisation. This study describes the identification and testing of reference genes with stable expression profiles in koala lymph node tissues across two genetically distinct koala populations. From the 25 most stable genes identified in transcriptome analysis, 11 genes were selected for verification using reverse transcription quantitative PCR, in addition to the commonly used ACTB and GAPDH genes. The expression data were analysed using stable genes statistical software - geNorm, BestKeeper, NormFinder, the comparative ΔCt method and RefFinder. All 13 genes showed relative stability in expression in koala lymph node tissues, however Tmem97 and Hmg20a were identified as the most stable genes across the two koala populations.

Lymphoma, Koala Retrovirus Infection and Reproductive Chlamydiosis in a Koala (Phascolarctos cinereus).

Koala retrovirus (KoRV) infection, thought to be associated with lymphoid neoplasia, and Chlamydia pecorum-related ocular and urogenital disease are both highly prevalent in eastern Australian koala (Phascolarctos cinereus) populations. However, in South Australian koalas, little is known about KoRV infection and C. pecorum-associated disease. We report the first South Australian case of lymphoma in a KoRV-A-positive female koala also affected by severe reproductive chlamydiosis. The koala was from the Mount Lofty Ranges population and was presented with hindlimb lameness. Clinical examination identified right stifle crepitus, enlarged superficial lymph nodes and paraovarian cysts. Necropsy examination revealed extensive cartilage degeneration and loss over the medial femoral condyle, solid femoral bone marrow, mesenteric and ovarian tumours, paraovarian cysts and purulent metritis. Histopathology confirmed lymphoma in the bone marrow, mesenteric lymph nodes and ovary, with infiltration and parenchymal effacement in the pancreas, adrenal glands and other tissues. Lymphoma, KoRV and chlamydiosis are being investigated further in this population.

Outbreaks of sarcoptic mange in free-ranging koala populations in Victoria and South Australia: a case series.

OBJECTIVE: To describe outbreaks of sarcoptic mange caused by Sarcoptes scabiei in free-ranging koalas in Victoria (December 2008 to November 2015) and South Australia (October 2011 to September 2014). METHODS: Koalas affected by mange-like lesions were reported by wildlife carers, veterinary practitioners or State Government personnel to the Faculty of Veterinary and Agricultural Sciences at The University of Melbourne and the School of Animal and Veterinary Sciences at The University of Adelaide. Skin scrapings were taken from live and dead koalas and S. scabiei mites were identified. Tissues from necropsied koalas were examined histologically. RESULTS: Outbreaks of sarcoptic mange were found to occur in koalas from both Victoria (n = 29) and South Australia (n = 29) for the first time. The gross pathological and histopathological changes are described. CONCLUSION: We present the first reported cases of sarcoptic mange outbreaks in free-ranging koalas.

Morbillivirus-associated unusual mortality event in South Australian bottlenose dolphins is largest reported for the Southern Hemisphere.

Cases of morbillivirus have been recorded in the Southern Hemisphere but have not been linked to significant marine mammal mortality. Post-mortems were conducted on 58 carcasses (44 Indo-Pacific bottlenose dolphins, two common bottlenose dolphins, 12 short-beaked common dolphins) from South Australia during 2005-2013, including an unusual mortality event (UME) in St Vincent Gulf Bioregion (SVG) during 2013. Diagnostic pathology, circumstance of death, body condition, age and stomach contents were documented for Indo-Pacific bottlenose dolphins. At least 50 dolphins died during the UME, 41 were Indo-Pacific bottlenose dolphins and most were young. The UME lasted about seven months and had two peaks, the first being the largest. Effect on the population is unknown. Diagnostic testing for morbillivirus was conducted on 57 carcasses, with evidence for infection in all species during 2011-2013. All tested UME bottlenose dolphins were positive for cetacean morbillivirus (CeMV), and the pathology included interstitial pneumonia, lymphoid depletion and syncytia. Concurrent pathologies, including lung parasite and fungal infections, and severe cutaneous bruising were observed in many dolphins. The event coincided with elevated water temperatures, a diatom bloom and significant fish die-offs. We conclude that the cause for the UME was multifactorial and that CeMV was a major contributor.

Pathological findings in wild harvested dugongs Dugong dugon of central Torres Strait, Australia.

The dugong Dugong dugon is classified as Vulnerable to extinction but may be endangered in some regions. Cause of death in stranded dugongs has not been determined in a large proportion of animals examined, with investigations hindered by limited information on dugong health and diseases, and paucity of knowledge of common or endemic pathological findings. Here we describe pathological findings in harvested dugongs from the relatively pristine area of central Torres Strait, and we characterise lesions attributable to drowning. Other recorded lesions were mild and predominated by host reaction to the presence of trematodes within the gastrointestinal tracts, liver and pancreas. Ascarid worm burdens were low in comparison to dugongs from developed coastlines. Hepatocellular lipofuscin and ferritin pigmentation were commonly observed, more pronounced in livers of older animals and concurrent with periportal and bridging fibrosis. Lesions attributable to drowning included incomplete collapse of lungs, dorsal or diffuse pulmonary congestion, mild intra-alveolar haemorrhage and oedema, mild interstitial oedema and rupture of peripheral alveolar septae with acute myofibre fragmentation and degeneration. No accumulation of foam or aspiration of water or particulate matter was observed, suggesting that dugongs 'dry drown'. Morphometric features of normal spleen are also presented. Characterisation of common pathological findings and those attributable to drowning in this species will aid in the interpretation of post mortem findings for the significant number of dugongs found deceased along urbanised coastlines.

Unusual features in four canine meningiomas.

Several subtypes of canine meningioma are recognized. This report describes four canine meningiomas with previously unreported features. The four affected dogs were of different breeds. Three of the affected dogs were male and aged 7-10 years. In one dog, age and gender were not recorded. Meningiomas were located intracranially (three dogs) or within the vertebral canal (one dog). Two meningiomas resembled gemistocytic astrocytomas, while one had focal features of a rhabdoid tumour; these three meningiomas also contained amyloid deposits. The fourth tumour, a secretory meningioma, was rich in amianthoid fibres (i.e. unusual collagen deposits containing giant collagen fibres). All of these features are also described in human meningiomas.

Pathological features of oxalate nephrosis in a population of koalas (Phascolarctos cinereus) in South Australia.

The wild and captive koala population of the Mt Lofty Ranges in South Australia has a high level of renal dysfunction in which crystals consistent with calcium oxalate have been observed in the kidneys. This study aimed to describe the pathological features of the renal disease in this population, confirm the composition of renal crystals as calcium oxalate, and determine whether any age or sex predispositions exist for this disease. A total of 51 koalas (28 wild rescues, 23 captive) were examined at necropsy, of which 28 (55%) were found to have gross and/or histological evidence of oxalate nephrosis. Histopathological features included intratubular and interstitial inflammation, tubule dilation, glomerular atrophy, tubule loss, and cortical fibrosis. Calcium oxalate crystals were demonstrated using a combination of polarization microscopy, alizarin red S staining, infrared spectroscopy, and energy-dispersive X-ray analysis with scanning electron microscopy. Uric acid and phosphate deposits were also shown to be present but were associated with minimal histopathological changes. No significant differences were found between the numbers of affected captive and wild rescued koalas; also, there were no sex or age predispositions identified, but it was found that oxalate nephrosis may affect koalas <2 years of age. The findings of this study suggest that oxalate nephrosis is a leading disease in this koala population. Possible causes of this disease are currently under investigation.

Ventricular and extraventricular ependymal tumors in 18 cats.

Ependymal tumors are reported rarely in domestic animals. The aims of this study were to examine the clinical and pathologic features of ventricular and extraventricular ependymomas and subependymomas in 18 domestic cats examined between 1978 and 2011. Parameters examined included age, sex, breed, clinical signs, and macroscopic and histopathologic features. The mean age of affected cats was 9 years, 4 months; median age, 8.5 years. There were 8 female and 4 male cats, and 6 cats for which sex was not recorded. Breeds included 10 domestic shorthaired, 2 domestic longhaired, 1 Persian, and 1 Siamese. Clinical signs included altered mentation or behavior, seizures, circling, propulsive gait, generalized discomfort, and loss of condition. The tumors often formed intraventricular masses and usually arose from the lining of the lateral or third ventricles, followed by the fourth ventricle, mesencephalic aqueduct, and spinal cord central canal. Three tumors were extraventricular, forming masses within the cerebrum and adjacent subarachnoid space. Histologically, 15 tumors were classified as variants of ependymomas (classic, papillary, tanycytic, or clear cell) and 3 as subependymomas. Tumors were generally well demarcated; however, 6 ependymomas focally or extensively infiltrated the adjacent neural parenchyma. Characteristic perivascular pseudorosettes were observed in all ependymomas; true rosettes were less common. Some tumors had areas of necrosis, mineralization, cholesterol clefts, and/or hemorrhage. This cohort study of feline ependymal tumors includes subependymoma and primary extraventricular ependymoma, variants not previously described in the veterinary literature but well recognized in humans.

Identification of Actinomyces denticolens as a cause of a soft tissue abscess in a horse.

CASE REPORT: A 6-year-old Arabian mare had a 4-week history of a subcutaneous mass (15 × 15 cm) at the base of the neck, cranial and distal to the prescapular lymph node on the right side. The mass was solid and painful on deep palpation. Ultrasonographic examination showed a soft-tissue abscess. Purulent aspirate was submitted for bacterial culture, which showed a moderate growth of an Actinomyces species. 16S rRNA gene sequencing was performed for definitive identification. Gene sequencing demonstrated close nucleotide homology with A. denticolens. Prolonged therapeutic management resulted in resolution of the abscess with a small scar. CONCLUSIONS: Speciation of actinomycetes is not a routine diagnostic procedure and 16S rRNA gene sequencing to identify A. denticolens as a cause of soft-tissue abscessation in horses in Australia has not been previously described. Practitioners should include this bacterial species in their differential diagnosis, particularly if abscesses do not respond to drainage and lavage alone.

Fatal aortic oesophageal fistula following oesophageal foreign body removal in a dog.

An eight-month-old male Pomeranian was presented with hypovolaemic shock 7 days after successful oesophageal foreign body removal. On presentation the dog was anaemic and no coagulation abnormalities were detected. A fluid-filled oesophagus was visible on thoracic radiography and frank blood was aspirated from the oesophagus following oro-oesophageal intubation. Fluid resuscitation and blood transfusions were administered but attempts at stabilisation were unsuccessful and the dog died. At post-mortem examination, a 2-mm aortic oesophageal fistula was identified on the ventral aspect of the aorta at the level of heart base that communicated with the overlying oesophagus. Aortic oesophageal fistula has been reported in human medicine and occurs secondary to a number of conditions including oesophageal foreign bodies. These prove fatal without rapid stabilisation and surgery.

Pleuropulmonary blastoma in an equine fetus.

Pleuropulmonary blastoma (PPB) is a rare biphasic tumor of children formed by mixed epithelial-and-mesenchymal elements. In this article, the authors report a pulmonary mass in an equine fetus with characteristics of PPB. A soft multicystic broad-based pleural mass was identified in the right caudal lung lobe. The mass comprised solid areas of loose mesenchyme, fenestrated by small ducts or large cystic areas lined by cuboidal epithelium. Mesenchymal elements had moderate anisocytosis, anisokaryosis, and cellular pleomorphism and were immunoreactive for vimentin. Epithelial cells lining ducts and cystic lumina were nonciliated and cuboidal with central round nuclei, minimal cellular pleomorphism, and strong immunoreactivity for cytokeratin. Pertinent characteristics in common with human PPB were the pleural-based location, the dual solid or delicate multiloculated cystic structure, the primitive mesenchymatous stroma fenestrated by well-differentiated cuboidal epithelial-lined lumina, and the occurrence during gestation.

Cutaneous papillomatosis and carcinomatosis in the Western barred bandicoot (Perameles bougainville).

A progressive wart-like syndrome in both captive and wild populations of the Western barred bandicoot (WBB) is hindering conservation efforts to prevent the extinction of this endangered marsupial. In this study, 42 WBBs exhibiting the papillomatosis and carcinomatosis syndrome were examined. The disease was characterized by multicentric proliferative lesions involving cutaneous and mucosal surfaces, which were seen clinically to increase in size with time. Grossly and histologically the smaller skin lesions resembled papillomas, whereas the larger lesions were most commonly observed to be squamous cell carcinomas. Large amphophilic intranuclear inclusion bodies were observed in hyperplastic conjunctival lesions of 8 WBBs under light microscopy. Conjunctival lesions from 2 WBBs examined using transmission electron microscopy contained a crystalline array of spherical electron-dense particles of 45-nm diameter, within the nucleus of conjunctival epithelial cells, consistent with a papillomavirus or polyomavirus. Conjunctival samples from 3 bandicoots that contained intranuclear inclusion bodies also demonstrated a positive immunohistochemical reaction after indirect immunohistochemistry for papillomavirus structural antigens. Ultrastructural and/or immunohistochemical evidence of an etiologic agent was not identified in the nonconjunctival lesions examined. Here we describe the gross, histopathologic, ultrastructural, and immunohistochemical findings of a papillomatosis and carcinomatosis syndrome recently identified in the WBB.

Klossiella quimrensis (Apicomplexa: Klossiellidae) causes renal coccidiosis in western barred bandicoots Perameles bougainville (Marsupialia: Peramelidae) in Western Australia.

Previous studies have described a range of Klossiella species parasitic in marsupial hosts. Klossiella quimrensis is the etiologic agent of renal coccidiosis in the peramelid marsupial hosts Isoodon obesulus and Perameles gunnii in Eastern Australia, but there is no previous report of klossiellosis in Western Australian peramelids. This study describes klossiellosis diagnosed by histology of renal tissue sections collected during necropsy of 20 Perameles bougainville between 2000 and 2005. Sporonts, sporoblasts, and macrogametes were identified within parasitophorous vacuoles of epithelial cells located near the renal corticomedullary junction. The prevalence of renal coccidiosis in P. bougainville diagnosed by renal histology is estimated at 30%. Only a single unsporulated sporocyst was detected by examination of cystocentesis-collected urine, indicating that microscopic evaluation of urine samples is an insensitive diagnostic test for detection of K. quimrensis in P. bougainville. This infection in P. bougainville is indirectly associated with mild multifocal interstitial lymphohistiocytic nephritis and is likely to be only minimally pathogenic in otherwise healthy individuals. Our study also extends the host and geographic range of K. quimrensis to include P. bougainville and Western Australia.

A new eimeria species parasitic in western barred bandicoots, Perameles bougainville (Marsupialia: Peramelidae), in western Australia.

Feces from western barred bandicoots, Perameles bougainville, examined during routine monitoring of captive breeding colonies and wild populations were frequently found to contain oocysts. Fecal oocysts from 1 individual housed at Kanyana Wildlife Rehabilitation Centre were allowed to sporulate in 2% potassium dichromate (K2Cr2O7) at room temperature. Sporulated oocysts are subspheroidal 18.8 X 17.9 (16.9-21.0 x 16.0-19.9) microm, with length/width (L/W) ratio of 1.05 (1.00-1.15), lack a micropyle and oocyst residuum, but they usually have a polar granule within a smooth trilaminate oocyst wall 1.0 (0.7-1.3) microm thick. Sporocysts are ovoid, 9.1 x 7.0 (8.1-10.8 x 6.1-8.6) microm, with L/W ratio of 1.32 (1.04-1.51), have a Stieda body, sporocyst residuum, and 2 comma-shaped sporozoites, each containing 2 spheroidal refractile bodies. Sporulation takes 2-5 days at room temperature. This is the first formal description of an Eimeria species parasitic in the order Peramelemorphia.