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Infection with Chlamydia pecorum is one of the main causes of progressive decline of koala (Phascolarctos cinereus) populations in Eastern Australia. Pathological changes associated with the chlamydial infection in the genital tract of female and male koalas have been widely described with reports of acute and chronic lymphoplasmacytic inflammation and the description of the cystic dilatation of the ovarian bursa. Although these disease manifestations can result in severe chronic inflammation, structural changes and even sterility, only limited data is currently available on the organism's distribution and associated histopathological and ultrastructural changes within the upper genital tract of affected females. This study examined the pathogenesis of the most common pathological lesion associated with chlamydiosis in female koalas, the cystic dilation of the ovarian bursa starting from the evidence that Chlamydia spp. induces disruption of the intercellular junctions in the epithelium of the reproductive organs in humans. Histology, immunohistochemistry (IHC) and transmission electron microscopy (TEM) were performed to evaluate the structural features and the expression of epithelial cell and cellular junctions' markers in affected bursae from 39 Chlamydia-infected female koalas. Epithelial cells from the ovarian bursae of one affected animal examined by transmission electron microscopy showed severe widening of the intercellular space, as morphologic evidence of disrupted permeability of the epithelial barrier. The epithelial cell-cell junctions markers E-cadherin, β-catenin and ZO-1 expressions were significantly reduced in samples from cystic bursae when compared to normal tissue samples (P 0.0001). On the other end, a significantly higher expression of the proliferation marker Ki67 was observed in cystic bursae compared to control samples (P 0.0001). As these proteins are required to maintain epithelial functional integrity and cell-cell adhesive interactions, their loss may permanently impair and affect female koala fertility and suggest the molecular basis of the pathogenesis of the cystic accumulation of bursal fluid within this tissue.

Bladder pain syndrome (BPS) is a debilitating disease in humans, particularly women, with patients experiencing chronic, intractable, lower urinary and pelvic pain. Although rodent models have been used, feline idiopathic cystitis (FIC) is a naturally occurring bladder disease of cats that is frequently considered to be the preferred model for BPS. Histologically, FIC is most similar to the non-Hunner BPS subtype. Histology is unnecessary for the clinical diagnosis of FIC but is of great value in elucidating the pathogenesis of this disease so that prevention and therapeutic interventions can be optimized. Further study of the histological features of FIC and BPS is required to determine the significance of Von Brunn's nests, which are invaginations of hyperplastic urothelium that have been associated with irritative bladder stimuli in animals and have been observed in FIC. We review the possible pathogenesis, histopathological similarities and differences between FIC and BPS, and highlight the potential of FIC as a model of BPS.

The terminology applied to canine prostatic epithelial lesions, especially carcinomas, is currently not standardized and this hampers the ability of pathologists to study the biological and clinical significance of these lesions. The aim of this review is to present the essential histomorphological diagnostic attributes of a wide spectrum of prostatic epithelial lesions in dogs. In addition to the traditionally recognized prostatic hyperplasia, hormonal atrophy, prostatitis, squamous metaplasia, adenocarcinoma and transitional cell (urothelial) carcinoma, new entities are described and discussed in order to provide veterinary pathologists with a basic atlas of common histological lesions of the canine prostate that is comprehensive and easy to use.

Congenital heart diseases have rarely been described in rabbits. The purpose of the present case report is to describe the clinical, radiographic, echocardiographic, and pathological features of a partial atrioventricular septal defect in a pet rabbit. A 3-month-old, 380-g male vaccinated pet rabbit was presented for decreased activity, increased respiratory rate and effort, anorexia, and decreased fecal output of 2 days duration. Total body radiographic images revealed severe cardiomegaly associated with enlarged caudal pulmonary vessels and increased interstitial to alveolar lung pattern. Echocardiographic imaging showed evidence of distended heart chambers, abnormal flow through the atria, and mitral valve regurgitation. The rabbit was treated with furosemide and an angiotensin-converting enzyme inhibitor but rapidly deteriorated and died. Necropsy confirmed the dilation of both ventricles and the presence of a partial atrioventricular septal defect associated with an ostium primum atrial septal defect just over the tricuspid valve and the mitral valve.

Studies documenting the application of ultrasonography to depict normal and pathological changes in koalas (Phascolarctos cinereus), especially in the male, are scarce. Sixty-two wild koalas were used in this study to define ultrasonographic protocols and features for the assessment of the male koala reproductive tract. Testis, epididymis and spermatic cord were examined using a hockey stick transducer. The normal koala testis showed a homogeneous echogenicity and an obvious hyper-echoic band corresponding to the tunica albuginea. The cauda epididymis was characterised by hypo- and hyper-echoic regions and was most effectively imaged in sagittal section. The koala prostate was assessed using a micro-curved transducer positioned midline, caudal to the bladder. On transverse section, it showed distinct margins and a well-defined internal structure, although the prostatic urethra was not apparent on most scans. To image the bulbourethral glands (BGs), the hockey stick transducer was placed lateral to the cloaca. BGIII was located just below the skin, while BGII was located deeper than BGIII. BGI was too small and not sufficiently echogenic to be detected. The ultrasonographic appearance of the BGs was similar to that of the testes but with more obvious hypo-echoic stippling. This comprehensive review of the ultrasonographic appearance of normal male koala reproductive tract can be used by veterinarians and others, in zoos or those working with wild koalas, during assessment of the reproductive tract of male koalas in relation to seasonal changes in accessory gland function or for the pathological investigation of reproductive lesions and infertility problems.

Proliferative inflammatory atrophy (PIA), which is comprised of highly proliferative but atrophic prostate epithelial cells in association with chronic inflammation, is considered a risk lesion for prostate cancer in men, while its role in canine prostate carcinogenesis is still unknown. We evaluated the value of immunohistochemical labelling for the basal cell marker cytokeratin-5 (CK5) in identifying PIA lesions in 87 samples of formalin-fixed and paraffin wax-embedded canine prostate. Canine PIA showed cytological features identical to the human counterpart and in most cases was associated with chronic lymphoplasmacytic inflammation. PIA lesions were identified in a higher number of CK5-labelled slides (43 out of 87) compared with slides stained by haematoxylin and eosin (HE) (24 out of 87). This lesion was frequently present in normal, hyperplastic and neoplastic canine prostates, although it was underestimated on evaluation of HE-stained slides. Therefore, CK5 can be considered a useful basal cell marker with high sensitivity and specificity for PIA.

Signal transducer and activator of transcription 3 (STAT3) and phosphatase and tensin homologue (PTEN) are, respectively, an oncogene and tumour suppressor gene whose dysregulated expression in human prostate cancer is associated with increased malignancy and poor prognosis. Both markers were evaluated in 12 samples of canine benign prostatic hyperplasia (BPH) and 17 canine prostatic carcinomas (PCs) by immunohistochemistry, to understand their possible role in canine prostate carcinogenesis. STAT3 was expressed in 25% and 82.35% of BPH and PC, respectively, with a significantly higher number of STAT3-positive cells in malignant compared with hyperplastic lesions. Three PCs had occasional nuclear expression of STAT3. PTEN was expressed in BPH and PC with a similar distribution and percentage of positive cells; however, four PCs were PTEN negative. Solid PCs contained more STAT3-positive and fewer PTEN-positive cells compared with the other subtypes. A reduced number of PTEN-positive cells was observed in PCs with a high Gleason score (GS10), while no association was demonstrated between STAT3 expression and Gleason score. The data suggest that overexpression of STAT3 and downregulation of PTEN may be an important step in canine prostate carcinogenesis and both markers may be related to the histological subtypes of PC and the degree of differentiation of neoplastic cells.

This study reports the first documented clinical case of a spermatic granuloma and varicocele in a marsupial. Initial clinical presentation included gross morphological changes in the left scrotal cord, epididymis and testis. Ultrasonography of the scrotum and spermatic cord, and gross and histopathological examination after hemicastration, confirmed the condition as a spermatic granuloma affecting the left caput epididymis, with a varicocele in the left proximal spermatic cord, which was causing azoospermia and infertility. Semen quality and serum testosterone secretion following a GnRH challenge was assessed prior to, and following surgery. After hemi-castration, an increase in androgen secretion to within normal reference ranges for the koala was observed with a subsequent increase in semen production and sperm quality resulting in the sire of a pouch young, 12 months later.

An 8.5-year-old, neutered female ferret (Mustela putorius furo) was presented with tachypnoea, polyuria, polydipsia, anorexia and depression. Radiographs revealed multiple osteolytic lesions of the bone, characterized cytologically by the infiltration of medium- to large-sized lymphocytes. The animal was humanely destroyed and post-mortem examination revealed multifocal masses obliterating the bone marrow of the mandible, right and left humeri and femur, and consisting of an infiltrative population of neoplastic lymphocytes. Immunohistochemical labelling for CD3 and CD79a revealed a CD3-positive neoplastic population. A diagnosis of polyostotic T-cell lymphoma was made, which is the first report of this condition in a ferret.

Two adult koalas (Phascolarctos cinereus) were presented for necropsy examination without any clinical history. A diffuse, severe gelatinous effusion was found in the abdominal cavity, while numerous 1-3 mm diameter, round, well-demarcated, multifocal to coalescing, raised, firm nodules containing a clear gelatinous fluid were scattered on the surface of the parietal peritoneum, diaphragm, liver, gastrointestinal tract and mesentery. Microscopically, the nodular lesions consisted of spindle-shaped to stellate neoplastic cells, with scant eosinophilic cytoplasm and moderate anisocytosis and anisokaryosis. The neoplastic cells were admixed with and surrounded by abundant acellular pale eosinophilic material that was stained by Alcian blue and only weakly by the periodic acid-Schiff reaction. Serosal proliferations are described rarely in koalas and to the authors' knowledge this is the first reported case of serosal myxosarcoma. The significance and pathogenesis of this condition in the koala population is unknown.

The purpose of this retrospective study is to evaluate the frequency and further characterize the pathological features of common and uncommon histological lesions in 111 canine prostatic samples. Benign prostatic hyperplasia, suppurative and non-suppurative prostatitis, and prostate cancer were observed individually or in combination in 45, 11, 68 and 50 samples, respectively. Six growth patterns of prostatic carcinoma were differentiated: papillary, cribriform, solid, small acinar/ductal, signet ring, mucinous. In a few cases, perineurial invasion and collagenous micronodules were observed. Lesions considered preneoplastic in men, such as high-grade prostatic intraepithelial neoplasia (HGPIN) and prostatic inflammatory atrophy (PIA), were observed in 27 and 21 histological samples, respectively. This study represents a detailed characterization of the different histological subtypes of canine prostate cancer. The awareness of the unusual patterns might be critical in avoiding diagnostic misinterpretation. The high prevalence of PIA and HGPIN underlines the reasonable chance of their detection in routine biopsy specimens.

Sixteen captive adult horned vipers (Vipera ammodytes ammodytes) were submitted for necropsy examination following a 2-week history of lethargy, anorexia and dyspnoea. Gross lesions included widespread haemorrhage, serosanguineous effusions in the body cavities and multiple pinpoint white to yellow foci in the liver. Microscopically, there was multifocal hepatic coagulative necrosis associated with intranuclear acidophilic inclusion bodies in sinusoidal endothelial cells. Similar endothelial lesions were observed in the myocardium, fat bodies, kidneys and spleen. Transmission electron microscopy revealed numerous virions (100-110 nm) in the nuclei of endothelial cells and intracytoplasmic enveloped virions (140-150 nm) were also found. The gross and histological findings and the ultrastructural features of the intranuclear inclusions and viral particles were consistent with herpesviral infection. To the best of our knowledge, these are the first reported cases of a lethal herpesvirosis in horned vipers and the second report in snakes.

Summary Homeobox genes are known to be examples of the intimate relationship between embryogenesis and tumourigenesis. Specifically, the HOXA13 gene plays a fundamental role in the development of the urogenital tract and external genitalia and in prostate organogenesis. There are no reports on the expression of HOXA13 in normal, hyperplastic or neoplastic canine prostate tissue or in other types of tumours. Six normal, 16 hyperplastic and 12 neoplastic canine prostates were examined microscopically and immunohistochemically with a polyclonal antibody specific for human HOXA13. An immunohistochemical score was generated. HOXA13 was expressed in the cytoplasm of epithelial cells in normal, hyperplastic and neoplastic prostates. The percentage of immunolabelled cells in all prostatic carcinomas (PCs) was greatly increased, with a score of 85.3 (±5.25) compared with normal (2 ± 0.71) and hyperplastic prostates (6.08 ± 2.21). The increase in HOXA13 expression in canine PCs suggests the involvement of this transcription factor in carcinogenesis and promotion of tumour growth.

A 22-day-old dicephalic spur-thighed tortoise (Testudo graeca ibera) died following a history of lethargy, anorexia and absence of defecation. The two heads were anatomically similar with independent reaction to external stimuli. The carapace showed doubled first and extra second vertebral scutes. Radiography and transplastronal ultrasonography, performed when the animal was alive, revealed two symmetrical stomachs and two asynchronous hearts. These findings were confirmed by necropsy examination. Oesophagus, liver, gallbladder and trachea were also duplicated. Other malformations included pyloric valve atresia of the left stomach, focal stenosis of the transverse colon and liver hypoplasia. Dicephalism rarely occurs in Testudinidae and its pathogenesis, still unclear, is discussed.

A 7-week-old male Saker falcon died with a history of severe refractory dyspnoea and respiratory signs. Microscopical lesions included moderate to severe lymphoplasmacytic inflammation of the middle ears, conjunctivae, third eyelids, choanae, salivary glands of the tongue, turbinates, larynx, trachea, syrinx and bronchi. The lesions were associated with variable numbers of Cryptosporidium spp., further confirmed by transmission electron microscopy and in-situ hybridization. Cryptosporidium baileyi was identified by DNA sequence analysis. C. baileyi may therefore be a cause of otitis media in raptors as it is in man. It is most likely that the middle ears of the Saker falcon acquired the infection through the eustachian tubes that originate near the pharynx in the oral cavity. This is the first description of otitis media associated with C. baileyi in a bird or a mammal except man.

One hundred and twenty-three cases of mycobacterioses were diagnosed in psittacine birds from a total of 9,241 submissions for necropsy examination or histopathology made to the California Animal Health and Food Safety Laboratory System between 1990 and 2007. The species affected most commonly were Amazon parrots (Amazona spp.)(n = 32; 26%) and grey-cheeked parakeets Brotogeris pyrrophterus (n = 23; 18.7%). The main gross findings on necropsy examination were enlarged and mottled pale livers and spleens and thickening of the small intestinal wall with numerous pale miliary nodules on the mucosa. Microscopical examination revealed infiltration of foamy macrophages and giant cells containing acid-fast bacteria in various organs. The gene encoding mycobacterial 65 kDa heat shock protein (hsp65) was amplified by nested polymerase chain reaction (PCR) from DNA extracted from 22 cases. The species of Mycobacterium involved was determined by analysis of restriction endonuclease patterns of the PCR products. Mycobacterium genavense was detected in 19 cases and Mycobacterium avium in two cases. One parrotlet (Touit spp.) had a mixed infection of both species of mycobacteria. It is concluded that M. genavense is the primary cause of mycobacteriosis in psittacine birds and the potential for zoonotic disease should be considered, especially for immunocompromised owners.

This paper describes the histopathological features and cellular distribution of T lymphocytes (CD3), B cells (CD79), follicular dendritic cells (FDC) and macrophages (alpha-1-antitrypsin, lysozyme) in lymphoid aggregates (Kisselev nodules) found in the lung, kidney and liver of wild boar ( Sus scrofa L.). The distribution of immunoreactive cells, tested for antibodies, was similar to that found in the cortex of lymph nodes: lymphoid follicles with germinal centers mainly consisting of CD79 + B cells with sparse interfollicular tissue (CD3 + T lymphocytes). This finding and the association of these structures with helminthic infections suggests that local humoral immunity is central to the organism’s response to parasitic challenge. The presence of follicular dendritic cells confirms the high degree of organization of these lymphoid-like structures. The role of other pathogenic factors and the induction of chronic inflammatory reaction in these ectopic lymphoid sites is also discussed.

Ocular squamous cell carcinoma (OSCC) is a well-characterized tumour occurring spontaneously in cattle and other mammalian species but not previously reported in the goat. This report describes the histological features of well-differentiated OSCCs in twin goats. Biomolecular investigations led to the identification of Papillomavirus-related DNA sequences within the neoplastic ocular parenchyma of both animals, but immunohistochemical and ultrastructural studies failed to demonstrate viral particles. A putative role of Papillomavirus in the aetiology of OSCC is discussed, together with other possible causative factors.

A female domestic duck (Anas platyrhynchos domesticus) suddenly died with abdominal distension and a large multilobulated mass within the coelomic cavity was found. Histologically and immunohistochemically, a benign mature tridermic teratoma was diagnosed and epithelial structures, cartilage, bone, myxoid tissue, adipocytes, muscle cells, cystic spaces lined by squamous epithelium, feather follicles, melanocytes and variable neural and glial differentiation were recognized. By electron microscopy, desmosomes, keratin bundles, dense core neurosecretory granules, aberrant Z-line material and Luse bodies were found. To our knowledge, this is the first report of tridermic benign intracoelomic teratoma of a duck in which an extensive immunohistochemical and electron microscopic examination has been performed and in which a common neural and glial differentiation has been demonstrated.