Lung worm (Marsupostrongylus spp.) infection in common brushtail possums (Trichosurus vulpecula).

Marsupostrongylus spp. are the metastrongyloid nematodes most commonly associated with verminous pneumonia in Australian marsupials. Currently, there is a scarcity of information regarding this parasite in the common brushtail possum (Trichosurus vulpecula). Thirty-four free-living possums submitted to two wildlife hospitals in Sydney, Australia, between 2008 and 2015 were diagnosed with verminous pneumonia on postmortem examination. The majority of possums presented ill with multiple comorbidities. However, only five cases had clinical signs of respiratory disease. Necropsy and histopathology revealed extensive lung lesions characterised by diffuse, mixed interstitial infiltrates of macrophages, lymphocytes and plasma cells with mild to marked concentrations of eosinophils. Bronchopneumonia, pulmonary oedema, interstitial fibrosis, atelectasis and type II pneumocyte hyperplasia were also present in most cases. Adult nematodes, first-stage larvae and embryonating eggs were present in the large airways and alveolar spaces. The parasites were definitively identified as Marsupostrongylus spp. in eight cases with presumptive diagnoses based on histopathological characteristics reached in a further 26 cases. Twenty-nine of the 34 affected possums were adults with no sex predisposition. A review of the brushtail possum records at Taronga Wildlife Hospital from 1999 to 2015 revealed no lungworm infections were reported in the 45 possums examined before 2008. However, between 2008 and 2015, 30 of 47 possums (63.8%) examined were diagnosed with metastrongyloid lungworms. This case series is the first detailed report of Marsupostrongylus nematodes in common brushtail possums and highlights the clinical and pathological features, along with epidemiological findings.

Design and chemical evaluation of reduced machine-yield cigarettes.

Experimental cigarettes (ECs) were made by combining technological applications that individually reduce the machine measured yields of specific toxicants or groups of toxicants in mainstream smoke (MS). Two tobacco blends, featuring a tobacco substitute sheet or a tobacco blend treatment, were combined with filters containing an amine functionalised resin (CR20L) and/or a polymer-derived, high activity carbon adsorbent to generate three ECs with the potential for generating lower smoke toxicant yields than conventional cigarettes. MS yields of smoke constituents were determined under 4 different smoking machine conditions. Health Canada Intense (HCI) machine smoking conditions gave the highest MS yields for nicotine-free dry particulate matter and for most smoke constituents measured. Toxicant yields from the ECs were compared with those from two commercial comparator cigarettes, three scientific control cigarettes measured contemporaneously and with published data on 120 commercial cigarettes. The ECs were found to generate some of the lowest machine yields of toxicants from cigarettes for which published HCI smoke chemistry data are available; these comparisons therefore confirm that ECs with reduced MS machine toxicant yields compared to commercial cigarettes can be produced. The results encourage further work examining human exposure to toxicants from these cigarettes, including human biomarker studies.

Combination therapy with digoxin and diltiazem controls ventricular rate in chronic atrial fibrillation in dogs better than digoxin or diltiazem monotherapy: a randomized crossover study in 18 dogs.

BACKGROUND: Atrial fibrillation (AF) with excessively high ventricular rates (VR) occurs in dogs with advanced heart disease. Rate control improves clinical signs in these patients. Optimal drug therapy and target VR remain poorly defined. HYPOTHESIS: Digoxin-diltiazem combination therapy reduces VR more than either drug alone in dogs with high VR AF. ANIMALS: Eighteen client-owned dogs (>15 kg) with advanced heart disease, AF, and average VR on 24-hour Holter > 140 beats per minute (bpm). METHODS: After baseline Holter recording, dogs were randomized to digoxin or diltiazem monotherapy, or combination therapy. Repeat Holter evaluation was obtained after 2 weeks; dogs were then crossed over to the other arm (monotherapy or combination therapy) for 2 weeks and a third Holter was acquired. Twenty-four hour average VR, absolute and relative VR changes from baseline, and percent time spent within prespecified VR ranges (>140, 100-140, and <100 bpm) were compared. Correlations between serum drug concentrations and VR were examined. RESULTS: Digoxin (median, 164 bpm) and diltiazem (median, 158 bpm) decreased VR from baseline (median, 194 bpm) less than the digoxin-diltiazem combination (median, 126 bpm) (P < .008 for each comparison). With digoxin-diltiazem, VR remained <140 bpm for 85% of the recording period, but remained >140 bpm for 88% of the recording period with either monotherapy. Serum drug concentrations did not correlate with VR. CONCLUSIONS AND CLINICAL IMPORTANCE: At the dosages used in this study, digoxin-diltiazem combination therapy provided a greater rate control than either drug alone in dogs with AF.

Genetic analysis of ventricular arrhythmia in young German Shepherd Dogs.

BACKGROUND: Ventricular arrhythmias (VA) and sudden death are inherited in German Shepherd Dogs (GSDs). OBJECTIVES: To estimate the genetic parameters (heritabilities and correlations) of 3 traits of VA (single premature ventricular complexes (PVCs), 2 consecutive PVCs (couplets), and 3 or more consecutive PVCs-ventricular tachycardia [VT]). ANIMALS: Three hundred and ninety-eight GSDs. METHODS: Prospective, observational, case control study. Dogs were phenotyped by 24-hour ambulatory ECG from 6 to 45 weeks of age. Edited ECG records included the number of incidents of (1) single PVCs, (2) couplets, and (3) VT. RESULTS: A data set of 1,239 Holter records from 398 GSDs was used to estimate genetic variables. Phenotypic correlations for affectedness (binarily coded 0/1) of the 3 traits ranged from 0.55 to 0.74, whereas correlations for severity (continuous values of 24-hour VA counts) ranged from 0.26 to 0.39. Estimates of genetic correlation among the severity traits were 0.06 to 0.27. Estimated heritabilities were 0.54, 0.54, and 0.46 for affectedness and 0.33, 0.69, and 0.69 for severity of PVCs, couplets, and VT, respectively. Month and year of birth and age at ECG recording had significant effects on all 3 traits. Season of ECG recording had a significant effect on the number of single PVCs, but not couplets or incidents of VT. Age of onset differed, with single PVCs appearing an average of 4 days earlier than couplets and VT. CONCLUSION: These results imply a strong genetic component for this disease but suggest that differences in the 3 traits should be taken into consideration in studies to identify the underlying genes.

Immunophenotyping of lymphosarcoma in South American camelids on six British premises.

Six cases of lymphosarcoma (LSA) in South American camelids (SACs) were selected from submissions to a diagnostic laboratory network servicing England and Wales. Immunophenotyping was carried out using anti-human CD3 and anti-human CD5 for T-cells; and anti-human CD79a and anti-human CD79b for B-cells/plasma cells. On the basis of labelling with mainly anti-CD3, four of the tumours were classified as T-cell tumours. One case was labelled with anti-CD79a and anti-CD79b, and was classified as a B-cell tumour. In the other case the majority of cells were labelled with anti-CD3, anti-CD79a and anti-CD79b, and was classified as a mixed T- and B-cell tumour. To the authors' knowledge this is the first reported attempt at immunophenotyping LSA in SACs on British premises and is only the second time that a presumptive mixed T- and B-cell LSA has been reported in alpacas and the veterinary literature in general.

Lidocaine converts acute vagally associated atrial fibrillation to sinus rhythm in German Shepherd dogs with inherited arrhythmias.

BACKGROUND: Lidocaine is most frequently used to treat ventricular arrhythmias. However, lidocaine may have an antiarrhythmic effect for certain supraventricular arrhythmias. HYPOTHESIS: We hypothesized that lidocaine would be effective in converting experimentally induced atrial fibrillation (AF) to sinus rhythm and that a decrease in the dominant frequency (DF) and an increase in the organization as judged by the spectral entropy (SE) would occur over the course of the conversion. ANIMALS: Seven German Shepherd (GS) Dogs. METHODS: Dogs were anesthetized with fentanyl and pentobarbital. AF was induced with standard pacing protocols while left and right atrial monophasic action potentials (MAP) were recorded. The power spectra from the MAP recordings were analyzed to determine DF and SE during treatment with boluses of 2 mg/kg lidocaine. RESULTS: Lidocaine converted AF to sinus rhythm in all dogs and all episodes (n = 19). Conversion time was 27-87 seconds. After atropine, sustained AF was not induced; however, 5 episodes of atrial tachycardia resulted, and 3 were converted with lidocaine. Frequency domain analysis of 12 conversion sequences showed that left and right DF of the MAP signals decreased from the time of injection to conversion to sinus rhythm (P < .001). Mean SE indicated a gradient between the left and right atria (P = .003) that did not change during conversion. CONCLUSIONS AND CLINICAL IMPORTANCE: Vagally associated AF in GS dogs is terminated with lidocaine. Lidocaine is likely an effective treatment in clinical dogs with vagally associated AF.

Immuno-histochemical demonstration of the role of chlamydiaceae in renal, uterine and Salpingeal disease of the koala, and demonstration of chlamydiaceae in novel sites.

Numerous bacteria, including Chlamydophila pecorum and Chlamydophila pneumoniae, are known to occur in diseased sites in koalas. In the present study the significance of such organisms was investigated by demonstrating their distribution in situ, in tissues collected opportunistically from wild koalas. Chlamydiaceae were demonstrated in epithelial cells and macrophages in association with pyogranulomatous pyelonephritis (8/11 kidneys), focal interstitial nephritis (3/21), and active inflammation and fibrosis of the entire upper female reproductive tract (10/10). In one case of pyelonephritis, Gram-positive cocci were also demonstrated in association with Chlamydiaceae and, in another, haematogenous filamentous bacteria appeared to be the sole aetiological agent. Three cases of chlamydial metritis were also superficially co-infected by a mixture of other bacteria. Chlamydiaceae were also demonstrated in pulmonary alveolar macrophages and epithelial cells in association with pneumonitis, and in hepatic and splenic macrophages in one koala. The study illustrated the prominent role of Chlamydiaceae in renal disease and disease of the uterus, uterine tube and ovarian bursa, with implications for pathogenesis and therapy. In addition, macrophages appeared to be a potential site of latent persistence from which systemic spread of infection might occur.

The roles of histology and immunohistology in the investigation of marsupial disease and normal lymphoid tissue.

This review acquaints scientists with current information related to the application of histology and immunohistology to the studies of normal lymphoid tissues and specific diseases in marsupials. Histological examination of tissue is a necessary prerequisite for immunohistological examination because it establishes tissue structure and detects specific areas of disease which allow the selection of smaller areas for immunohistological examination. Information is provided on the basic techniques of histology. Immunohistology (immunohistochemistry) refers to the identification of antigenic determinants of specific substances (proteins) by the application of antibodies to histological sections. Information is provided on a technique for enzyme based, avidin-biotin enhanced immunohistology, and on antibodies that can be used to mark disease agents or marsupial tissues and cells. A summary is provided of the available information on studies of the histology and immunohistology of normal marsupial lymphoid tissue (thymus, spleen, lymph nodes and mucosa associated lymphoid tissue), and of selected marsupial diseases such as chlamydiosis and lymphosarcoma in koalas.

Histopathological and immunohistochemical investigation of naturally occurring chlamydial conjunctivitis and urogenital inflammation in koalas (Phascolarctos cinereus).

Formalin-fixed conjunctival and urogenital (urinary bladder, urogenital sinus and prostate or penis, or both) samples obtained from 29 free-living koalas were examined histopathologically and immunohistochemically for the presence and character of inflammation and for evidence of chlamydiae. Five koalas had no inflammation at any site examined and were chlamydia-negative. Twenty-four koalas had inflammation at one or more sites and 18 were positive for chlamydiae by serology or antigen detection tests, or both. Histopathological and immunohistochemical findings were consistent with those seen in chlamydial infections in other species. The inflammatory infiltrate was most dense in the lamina propria-submucosa and, in most tissues, predominantly consisted of lymphocytes and plasma cells. Neutrophils and macrophages were variable in number. Lymphocytes in uninflamed and inflamed tissues consisted largely of T cells. B lymphocytes and plasma cells were mainly distributed immediately beneath the epithelium, but T cells were widely distributed. MHC H-positive lymphoid cells were present in variable numbers and, in some inflamed tissue samples, epithelial cell labelling was also seen. Chlamydial inclusion bodies were uncommon in routinely stained sections. Immunoperoxidase labelling for chlamydiae was positive in 16 of 52 inflamed tissues. The proportion of positive test results for chlamydial antigen by any method was directly related to the severity of inflammation.

Immunohistochemical characterization of lymphosarcoma in two alpacas (Lama pacos).

Species cross-reactive anti-peptide antibodies were assessed in formalin-fixed tissue for use in immunophenotyping of lymphosarcoma in two alpacas. Diagnosis of lymphosarcoma was made by routine histopathological examination. Primary antibodies used for immunophenotyping were anti-human CD3 and anti-human CD5 for T cells; and anti-human CD79a and anti-human CD79b for B cells/plasma cells. In one case, most of the neoplastic cells were labelled with both anti-CD3 and anti-CD79b, and smaller numbers were labelled with anti-CD79a. The other case was classified as a B-cell tumour on the basis of labelling of the majority of neoplastic cells with anti-CD79b and anti-CD79a. This is the first recorded attempt at immunophenotyping lymphosarcoma in alpacas and, to our knowledge, the first record of presumptive co-expression of T- and B-cell-associated molecules in lymphosarcoma in the veterinary literature.

Protein microanalysis of animal tears.

Sub-microlitre volumes of normal koala, mouse, dog, rat and cat tears were fractionated using size exclusion-high performance liquid chromatography (SE - HPLC), giving reproducible profiles which were different for each species. Microlitre volumes of tears were also fractionated using sodium dodecylsulphate-polyacrylamide gel electrophoresis (SDS - PAGE), resulting in good separation of individual tear proteins with a species specific distribution. Tears from koalas with conjunctivitis and mice with keratitis were similarly examined and showed mostly quantitative changes. These simple, rapid techniques gave reproducible results and, in contrast to conventional separation techniques, used easily obtainable volumes (as little as 0.75 microl) of tears. Their expansion could allow isola tion, identification and quantitation of individual tear components, enabling effective investigation of changes occurring in disease.

Traumatic injuries occurring in possums and gliders in the Blue Mountains, New South Wales.

Twenty common brushtail possums (Trichosurus vulpecula), 23 ringtail possums (Pseudocheirus peregrinus) and five sugar gliders (Petaurus breviceps) from the Blue Mountains, New South Wales, Australia were evaluated for traumatic injuries between 1989 and 1990. Ten brushtail possums and five ringtail possums were hit by motor vehicles with injuries primarily to the anterior of the body. Fifteen ringtail possums and all sugar gliders were attacked by cats. Four brushtail possums were attacked by dogs. The remaining nine possums had evidence of intraspecific fighting (n = 2) or other types of trauma. Brushtail and ringtail possums were presented primarily during their main breeding seasons. There was no sex predilection. More ringtail than brushtail possums were subadults and these were injured primarily at the time of dispersal.

Management of peritonsillar abscess.

A prospective, randomized clinical trial was conducted on 60 patients with confirmed peritonsillar abscess to: (1) compare the safety and efficacy of permucosal needle aspiration with that of incision and drainage; (2) assess whether admission to hospital and treatment with intravenous antibiotics is necessary; (3) culture the pus obtained, in order to decide on a rational antibiotic regime. Of the 60 patients, 30 were randomized to the needle aspiration group, and 30 to the incision and drainage group. The initial success rate was 87 per cent (26 of 30 patients) with needle aspiration, and 90 per cent (27 of 30 patients) with incision and drainage. Two patients required hospital admission, for rehydration and intravenous antibiotics. The commonest organisms cultured were streptococci (62 per cent); 97 per cent of all patients responded to penicillin. This study indicates that most patients with peritonsillar abscess may successfully and safely be treated by permucosal needle aspiration, and oral penicillin, on an out-patient basis.

Proctitis associated with chlamydial infection in a koala.

OBJECTIVE: To describe proctitis associated with chlamydial infection in a koala. DESIGN: A pathological study. ANIMAL: A free living, male koala aged 17 years. PROCEDURE: Rectum was examined histologically and chlamydial organisms visualised using Giminez' stain and an immunoperoxidase staining method using an anti-Chlamydia lipopolysaccharide (genus specific) antibody. RESULTS: An aged koala presented for euthanasia was found to have asymptomatic chronic proctitis, cystitis, prostatitis, urethritis and conjunctivitis associated with chlamydial infection. Inflammation was severe in the terminal rectum and extended into the proximal common vestibule. Chlamydial organisms were visualised in the rectal surface epithelium using Giminez' stain and an immunoperoxidase staining method. Organisms were also detected in the epithelium of the bladder, prostate and urethra. CLINICAL IMPLICATIONS: Possible modes of transmission for the rectal infection are direct sexual transmission or ascending infection by organisms shed from the urogenital tract into the common vestibule. Previously unreported chlamydial proctitis in the koala may represent a potential reservoir of infection for other koalas.

Thymic lymphosarcoma of T cell lineage in a koala (Phascolarctos cinereus).

OBJECTIVE: To diagnose and characterise thymic lymphosarcoma in a koala. DESIGN: A pathological case. ANIMAL: Seven-year-old female koala. PROCEDURE: The neoplastic process was investigated macroscopically, haematologically, histologically and immunohistologically. RESULTS: The koala had difficulty swallowing because of a medial swelling in the lower neck. Biopsy of this mass and blood examination revealed lymphosarcoma with a leukaemic manifestation; necropsy and histopathological examination showed the mass to be thymus. Palatine tonsils, cervical, axillary and mesenteric lymph nodes, spleen, liver, gut, bronchi, genitalia and bone marrow were infiltrated by neoplastic cells. Immunohistological staining of the thymic mass, cervical and mesenteric lymph nodes, bone marrow, spleen and gut revealed the neoplastic cells to be of T lymphocyte origin (positive for both anti-human CD3 and CD5). CONCLUSIONS: It is speculated that the neoplastic process originated in the thymus and was disseminated by bloodborne neoplastic cells. This first report of thymic lymphosarcoma in a marsupial confirms that antibodies raised originally to investigate human lymphoid neoplasia can cross-react with neoplastic lymphocytes in koalas.

Diabetes mellitus in a koala (Phascolarctos cinereus).

OBJECTIVE: To describe a case of diabetes mellitus in a koala (Phascolarctos cinereus). DESIGN: A case report with controls. PROCEDURES: We describe clinical and laboratory findings in a 6-year-old, free-living, female koala presented with traumatic injury and subsequently found to have polydipsia, hyperglycaemia and glucosuria. Over a 5 week period, serum biochemical analyses, haematological examinations, urinalyses, measurement of serum insulin and fructosamine concentrations, necropsy, histopathological examination of a range of tissues and immunohistochemical examination of the pancreas for insulin-containing cells were done. For reference purposes, serum insulin and fructosamine concentrations were determined in four and two healthy koalas, respectively, and three healthy koalas' pancreases were examined histologically and immunohistochemically. RESULTS: The koala had persistent hyperglycaemia, hyperlipidaemia, hyponatraemia, hypochloraemia and glucosuria. Serum insulin concentration of the diabetic koala was only marginally smaller than that of healthy koalas, but all concentrations were smaller than reference concentrations in dogs and people. Fructosamine concentration did not allow the diabetic koala to be distinguished from healthy koalas and concentrations of all koala analytes were greater than expected for healthy dogs and people. Histopathological examination revealed extensive degeneration of pancreatic islet cells and fatty infiltration of hepatocytes. Immunoperoxidase staining revealed decreased or absent insulin in the beta calls of the affected koala. CONCLUSION: Clinical signs, clinicopathological results and histopathological changes were consistent with diabetes mellitus. The pathogenesis of the condition could not be determined but may have been related to the administration of a parenteral corticosteroid preparation, the stress of capture or tissue damage and inflammation.

Lymphoid neoplasia in the koala.

OBJECTIVE: Correlation of immunophenotype with history, anatomical and morphological features of lymphoid neoplasia in the koala. METHODS: Routine necropsies were performed on 51 koalas with suspected lymphoid neoplasia between 1986 and 1997 in New South Wales and Queensland. Immunophenotyping was by an immunoperoxidase method utilising species cross-reactive antibodies raised against human lymphocytes and an antibody raised against koala IgG. Cases were classified according to organs and tissues affected and the morphological features of neoplastic cells. RESULTS: Twenty-six (51%) of the cases were of the T cell immunophenotype, 12 (24%) were of B cell immunophenotype and 13 (25%) did not stain. The age and sex of koalas did not correlate with immunophenotype (P = 0.686 and P = 1.000, respectively). Thirty-two cases were leukaemic and 36 had multiple organ involvement, probably reflecting presentation of koalas at advanced stages of disease. Abdominal tissue involvement was most common (44 cases), followed by nodal (32), atypical (21) and cervicomediastinal (14). The T cell immunophenotype was over-represented among the leukaemic cases (P = 0.013). Generally, the T cell immunophenotype predominated except for many affected atypical tissues. Neoplastic cells were mostly of medium nuclear size with round to oval nuclei. No correlations were found for cell morphology, mitotic index and immunophenotype. CONCLUSION: The prognostic value of an immunophenotypic, anatomical and morphological basis for the classification of lymphoid neoplasia in the koala currently is limited by the need to detect these neoplasms at an early age, the requirement for freshly fixed tissues and the restricted range of available cross-reacting antibodies.

Nasopharyngeal cryptococcosis.

Naturally occurring cryptococcosis in five cats, a dog and a koala is described. Involvement of the nasopharynx was documented in all patients, and nasopharyngeal mass lesions accounted for the major presenting complaints in four. Signs referable to nasopharyngeal disease included snoring, stertor, inspiratory dyspnoea and aerophagia. Diagnoses were made by caudal rhinoscopy using a retroverted flexible endoscope, vigorous orthograde flushing with saline, or at necropsy. Concurrent cryptococcal rhinitis was present in all cases, although involvement appeared limited to the caudal nasal cavity in most cases. Typical signs of nasal cavity disease, such as sneezing and nasal discharge, were often absent. Treatment of nasopharyngeal cryptococcosis should include physical dislodgement or debulking of lesion(s) to provide immediate alleviation of upper airway obstruction, followed by systemic antifungal therapy to eliminate residual infection from the nasal cavity. Infections caused by Cryptococcus neoformans var gattii accounted for a disproportionately large number of these cases.

Low back pain in mineral sand mine workers. Incidence and management.

OBJECTIVES: To establish the prevalence of low back pain suffered by workers in three mineral sand mining companies operating in the south west of Western Australia; to determine what use was made of health care providers by those experiencing low back pain; to derive the perceptions of the value of the treatment for low back pain by health care providers. METHOD: A total of 350 questionnaires were distributed to sand mine workers who were asked to complete the questionnaires which were collected 1 week later. RESULTS: completed questionnaires were returned by 204 workers giving a 58% response rate. Seventy-seven percent of male workers and 60% of female workers could remember suffering low back pain sometime in their lives. Low back pain was experienced by 61% of male sufferers and 57% of female sufferers at least two to three times a month. A total of 16% of men and 12% of women experienced low back pain on a daily basis while 30% of men and 22% of women reported that the type of work they were doing increased their low back pain. Only 19% of all male workers and 6% of all female workers had ever taken time off work due to low back pain with the average time taken off work for an acute episode, being 14 days. Overall, 47% of respondents indicated that the treatment received from general practitioners was ineffective, and only 16% of respondents assessed GPs as being better than average. Chiropractors were rated higher than physiotherapists or general practitioners in providing the most effective treatment for low back pain. Mobilising exercises were considered to be better treatment than analgesics or anti-inflammatory medication. CONCLUSION: Low back pain is a common problem among mineral sand mine workers who preferred the services of the chiropractor or the physiotherapist to the general practitioner. Physical treatment modalities with stretching and mobilising exercises were preferred to pharmacological treatment.

Computed tomographic anatomy of the nasal cavity, paranasal sinuses and tympanic cavity of the koala.

OBJECTIVE: To use cross-sectional imaging (helical computed tomography (CT)) combined with conventional anatomical dissection to define the normal anatomy of the nasal cavity and bony cavitations of the koala skull. METHODS: Helical CT scans of the heads of nine adult animals were obtained using a multislice scanner acquiring thin slices reconstructed in the transverse, sagittal and dorsal planes. Subsequent anatomical dissection permitted confirmation of correct identification and further delineation of bony and air-filled structures visible in axial and multiplanar reformatted CT images. RESULTS: The nasal cavity was relatively simple, with little scrolling of nasal conchae, but bony cavitations were complex and extensive. A rostral maxillary recess and ventral conchal, caudal maxillary, frontal and sphenoidal paranasal sinuses were identified and characterised. Extensive temporal bone cavitation was shown to be related to a large epitympanic recess. CONCLUSIONS: The detailed anatomical data provided are applicable to future functional and comparative anatomical studies, as well as providing a preliminary atlas for clinical investigation of conditions such as cryptococcal rhinosinusitis, a condition more common in the koala than in many other species.