Haematological, biochemical and selected acute phase protein reference intervals for weaned female Merino lambs.

BACKGROUND: Merino lambs are currently the subject of much research into the welfare aspects of mulesing and mulesing alternatives. OBJECTIVE: Obtain haematology, biochemistry and acute phase protein reference intervals using modern methodologies for female Merino lambs. METHOD: Blood was collected from 50, weaned, 9- to 16-week-old, female Merino lambs. Haematology and biochemistry panels were performed using routine automated methods. The acute phase proteins, fibrinogen, serum amyloid A and haptoglobin, were also measured using commercially available techniques. The reference intervals were determined to be the central 95% of results. RESULTS: Differences in the concentrations for some analytes were seen when compared with reported studies in sheep, but may be explained by the use of sheep of a different signalment, as well as different methodologies for analyte measurement. Overall, most analytes gave similar values to those previously reported in other studies. Notable exceptions were alkaline phosphatase, phosphate and globulins, for which the different results were often attributed to the younger age of the sheep in the present study, and platelets and creatine kinase, for which the elevated levels may have been a result of stress and muscle exertion associated with blood collection and husbandry practices. CONCLUSION: Established haematological, biochemical and acute phase protein reference intervals are necessary for the investigation of the systemic impact of mulesing and mulesing alternatives and for the investigation of systemic diseases affecting weaned, 9- to 16-week-old, female Merino lambs in general.

Erythrocytic pyruvate kinase deficiency and AB blood types in Australian Abyssinian and Somali cats.

OBJECTIVE: To determine the frequency of the mutant pyruvate kinase (PK) allele, haematological parameters and AB blood types of Abyssinian and Somali cats in Australia. DESIGN: Complete blood cell and reticulocyte counts, DNA PK mutation testing and blood typing were performed in all cats. RESULTS: A total of 60 cats (36 Abyssinians, 24 Somalis) were included (37 females, 23 males). For the mutant PK allele, three female Somalis were homozygous (affected, 5%), 17 cats were heterozygous (carrier, 28%) and 40 cats tested negative (normal, 67%). Pedigree analysis revealed common ancestry of affected and many carrier cats. Of affected cats, two had regenerative anaemias and all had reticulocytosis (range 64-390 x 10(9)/L; P < 0.001 compared with normal or carrier cats). The only consistent historical sign was lethargy. One affected cat was euthanased 18 months after testing, because of anaemia, neutropenia, anorexia and weight loss. The mutant allele frequency was 0.19 overall (0.29 in Somalis, 0.13 in Abyssinians). All cats had blood type A. The commercial blood typing card method incorrectly identified 12 cats as having type AB blood. CONCLUSIONS: The frequency of the mutant PK allele is high in Australia. Screening for PK deficiency is indicated before mating and in individual cats of these breeds, even in the absence of anaemia and especially when there is reticulocytosis. Although all cats in the present study had blood type A, blood type B is common in these breeds worldwide. Retyping of any AB typed cats by a laboratory technique is recommended.

Potential Pathogens Reported in Species of the Family Viverridae and Their Implications for Human and Animal Health.

The Viverridae is a family of nocturnal carnivores including civets, genets and African linsangs. While a list of known organisms isolated from a species is an essential tool for population management, this review represents the first attempt to collate published reports of organisms isolated from viverrids. A wide range of organisms, including 11 viruses, eight bacterial species, one internal arthropod species, representatives from eight genera of protozoan, 21 genera of nematode, seven genera of cestode, eight genera of trematode and six genera of external arthropod (mites, ticks and louse), have been reported in literature spanning over a century of research. Many of these are capable of infecting multiple hosts, including humans. This is of concern given the anthropogenic factors that bring humans and domestic species into close contact with viverrids, facilitating transmission and spillover of organisms between groups. These factors include trade in viverrids for human consumption, captive management in zoos, rescue centres or on commercial breeding farms, and the increasing overlap of free-ranging viverrid distribution and human settlement.

Detection of Anaplasma platys and Babesia canis vogeli and their impact on platelet numbers in free-roaming dogs associated with remote Aboriginal communities in Australia.

OBJECTIVE: To detect Anaplasma platys and Babesia canis vogeli infection, using polymerase chain reaction (PCR)-based assays, in free-roaming dogs associated with eight Aboriginal communities in remote areas of Australia and to determine the impact of infection through the assessment of platelet numbers. PROCEDURES: Blood samples from 215 dogs were screened by PCR for A platys and B canis vogeli using established genus-specific DNA primers for the 16S and 18S rRNA genes respectively. Both A platys DNA and B canis vogeli DNA were confirmed from the screening PCR either by sequencing or by the use of species-specific primers. Peripheral blood films from 92 of the 215 dogs were used to estimate platelet numbers through an indirect method. RESULTS: Of 215 dogs, 69 (32%) were positive for A platys, 22 (10%) for B canis vogeli and 24 (11%) for both. The two organisms were detected singularly and as coinfection in all communities. For the 92 dogs in which peripheral blood films were examined, the mean estimated platelet counts for the non-infected dogs was 318 x 10(9)/L, those infected with A platys alone was 256 x 10(9)/L, those with B canis vogeli alone was 276 x 10(9)/L and those infected with both parasites was 169 x 10(9)/L. In young dogs, infection produced significantly decreased mean platelet counts when compared to uninfected dogs. Thrombocytopenia (< 200 x 10(9)/L) was detected in 18 (51%) dogs infected with A platys alone, 3 (33%) dogs infected with B canis vogeli alone, 13 (72%) dogs coinfected, and 8 (27%) uninfected dogs. CONCLUSIONS: A platys and B canis vogeli infection, either singularly or together, was widespread in free roaming dogs associated with remote Aboriginal communities in the Northern Territory and north-western New South Wales. Moreover, both A platys and B canis vogeli infections were associated with a reduction in mean platelet numbers in dog populations, particularly in young dogs. The fact that 51% of dogs infected with A platys alone and 72% dogs coinfected were thrombocytopenic compared to 27% of uninfected dogs suggests that the organism alone or in combination with B canis vogeli has the potential to cause thrombocytopenia and perhaps contribute to a clinical bleeding disorder in infected dogs.

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.

Characterization and histogenesis of tumors in the hairless mouse produced by low-dosage incremental ultraviolet radiation.

Tumors were induced in the HRA/Skh-1 hairless mouse by repeated irradiations of minimally erythemal and suberythemal doses of UV radiation. Aspects of tumor induction were recorded using a combined system of mapping and gross descriptive classification. Tumors of epithelial and dermal (mesenchymal) origin were confirmed histologically and their types correlated well with those reported by earlier investigators. Among those classified, however, appendage tumors and hemangiomas have rarely been described. The progression to malignancy of epithelial tumors was systematically characterized and was a consistent histogenic feature in our experiments. Squamous cell carcinomas represented a final stage for development arising ab initio or from other forms, in particular papillomas which commonly passed through intermediate forms toward definite malignancy. While confirming previous studies of UV-induced tumors, this report extends our knowledge of their dynamics as this bears upon any experimental objective which includes an assessment of tumorigenicity.

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.

Topical urocanic acid enhances UV-induced tumour yield and malignancy in the hairless mouse.

Epidermal urocanic acid has been postulated to be the mediator of the specific state of immunosuppression induced by UV irradiation, by which UV-initiated tumour cells are able to evade normal recognition and can survive to grow progressively into malignant tumours. These experiments demonstrate that topical application of UV-irradiated urocanic acid systemically suppresses the contact type hypersensitivity response to oxazolone in hairless mice. In addition, topically applied urocanic acid markedly increases the overt tumour yield and the degree of malignancy in hairless mice exposed chronically to daily minimally erythemal doses of simulated solar UV light. Topical urocanic acid also increases the number of latent UV-initiated tumours, detectable by croton oil promotion. Therefore UV photoproducts of urocanic acid can both systemically suppress contact hypersensitivity in the epidermis, and also enhance early survival of UV-initiated tumour cells resulting in augmentation of UV photocarcinogenesis.

Individual serum bile acids as early indicators of carbon tetrachloride- and chloroform-induced liver injury.

Individual serum bile acids (SBA) are emerging as potentially useful early indicators of liver injury. This study was undertaken to compare the usefulness of individual SBA with the routinely used assays for detecting the effects of the hepatotoxicants carbon tetrachloride (CCl4) and chloroform (CHCl3). Serum samples were assayed for liver injury by determination of alanine aminotransferase (ALT), aspartate amino-transferase (AST), alkaline phosphatase (ALP), bilirubin and total bile acid (by enzymatic kit). These results were compared with levels of individual SBA measured by high performance liquid chromatography (HPLC). Liver samples from CCl4-treated rats were taken for light and electron microscopic examination. The highest dose for each chemical caused increases in serum ALT and AST but not ALP. Chloroform at the highest dose increased bilirubin. Total SBA levels as assayed by the kit were elevated in response to CCl4 and CHCl3 at doses below which serum enzymes and bilirubin were increased. Some individual SBA were increased at a still lower dose for each of these two chlorinated solvents. At the lowest dose of CCl4 tested no consistent light microscopic or ultrastructural changes were found. At all the higher doses periacinar cells displayed typical accumulation of lipid droplets and degranulation and dilation of rough endoplasmic reticulum. The extent of the ultrastructural changes were dose-dependent. Thus individual SBA assayed by HPLC may be considered as a very sensitive indicator of liver injury induced by the classical hepatotoxicants carbon tetrachloride and chloroform.

The characterization of squamous cell carcinoma induced by ultraviolet irradiation in hairless mice.

Squamous cell carcinomas (SCCs) induced by ultraviolet irradiation in hairless mice were characterized according to their growth, gross appearance and light and transmission electron microscopic features. SCCs arose directly from irradiated skin (ab initio) or progressed from pre-existing epidermal tumours and lesions. SCCs could be graded using guidelines established for human tumours. SCCs comprised 60.8% of the tumours examined. Of these, 35.6% were designated as grade 1, 27.7% as grade 2, 7.9% as grade 3 and 28.7% as grade 4. Spindle cell tumours suspected of being SCCs were included in grade 4. Grades 1, 2 and 3 could not be distinguished on the basis of growth and gross appearance. Those arising ab initio presented as either red, ulcerated lesions or as raised, white, verrucose lesions. Grade 4 SCCs that arose ab initio presented as rapidly growing, red, spherical lesions. Those that arose from pre-existing tumours or lesions had no characteristic appearance, and variable growth. Light microscopically, grade 4 SCCs with an obvious point of origin from epidermis or other epidermal tumours, and putative grade 4 SCCs without such a point of origin, were characterized commonly by spindle cells, pleomorphic giant or multinucleated cells and individual cell reticular fibres. Ultrastructurally, spindle cells, although poorly differentiated, were distinct from flibroblastic proliferations and had few tonofilaments or desmosomes, and were inconsistently surrounded by basal lamina-like material. On the basis of these characteristics, and despite inconclusive positivity with immunoperoxidase staining for keratin and prekeratin, it was concluded that these spindle cell tumours were most probably of identical squamous cell origin.(ABSTRACT TRUNCATED AT 250 WORDS)

Characterization of UV induced keratoacanthoma-like lesions in HRA/Skh-1 mice and their comparison with keratoacanthomas in man.

UV induced keratoacanthoma-like lesions in mice were studied grossly, light microscopically and electron microscopically. The tumours varied in their degree of cell organization and keratinization but all exhibited downward growth and had a continuous basement membrane. Ultrastructurally, the keratinocytes displayed villous distortion of their plasma membranes, and at times the basal lamina of the epidermal-dermal junction showed focal discontinuation. The keratoacanthoma-like lesions in mice had similarities of appearance to keratoacanthoma in man but showed no regression and regularly progressed to squamous cell carcinoma. This clinical course is dissimilar to that of keratoacanthoma in man which suggests that the use of the term is inappropriate for these UV induced tumours. Moreover, in the context of our experimental system and a dynamic picture of tumour development where tumour types can be seen as stably arising and continuing entities or, a progressive sequence for which squamous cell carcinoma represents an end stage, it is not appropriate to view the keratoacanthoma-like lesion in mice as an entity distinct from the spectrum of UV induced tumours progressing from benignity to malignancy.

Ultrastructure of ultraviolet radiation-induced hairless mouse skin carcinogenesis, with special reference to the epidermal-dermal junction.

The ultrastructure of ultraviolet (UV)-induced skin pathology was studied in mice to complement previously reported gross and light microscopic findings, and to assess further the usefulness of the animal model for study of sunlight associated epidermal tumours in man. Hairless albino (HRA/Skh-1) mice were exposed to a minimal erythemal dose from a filtered light source emitting both UVA and UVB, approximating solar emission. Samples of normal and hyperplastic skin, pedunculated papillomas, carcinomas in situ and invasive squamous cell carcinomas were processed for transmission electron microscopy once their identity was confirmed by light microscopic examination. Keratinocyte pleomorphism became more marked and cell to cell contact diminished as malignancy developed. For papillomas, carcinomas in situ and invasive squamous cell carcinomas, there was a progressive disruption of the epidermal junction which became marked upon frank invasion. Most of the differences between the various categories of pathological change, therefore, were not absolute but rather of degree, supporting the notion that invasive squamous cell carcinoma represents an end stage for malignancy which may arise de novo, directly from hyperplastic skin, or proceed from other tumour types. The similarity in structure of the mouse tumours to comparable tumours in man supports the usefulness of the animal model and suggests that the results have implications for sunlight associated tumours in man.

Analysis of feline dual lymphocyte populations observed by flow cytometry.

Two discrete lymphocyte populations were observed commonly on flow cytometric analysis (FCM) of feline lymphocyte subsets. The identity of these populations as small and large lymphocytes was established by correlating data from FCM with that from peripheral blood films. Dual lymphocyte populations were more likely to be seen in feline immunodeficiency virus-positive (FIV(-)+ ve) cats but their occurrence was not affected by health status, age, gender or breed. FIV(-)+ ve cats had a significantly higher proportion of large lymphocytes than FIV-negative (FIV(-)- ve) cats. However, FIV(-)+ ve cats had significantly fewer small lymphocytes than FIV(-)- ve cats but similar numbers of large lymphocytes. Lymphocyte subset analysis revealed that small lymphocytes had a greater proportion of CD4+ cells than large lymphocytes, regardless of the FIV or health status of the cat. In FIV(-)- ve cats, small lymphocytes had a greater proportion of Pan T + lymphocytes than large lymphocytes, but the converse was seen in FIV(-)+ ve cats. The proportion of CD8 + cells was higher in small lymphocytes than large lymphocytes in well FIV(-)- ve cats but this distinction was not seen in sick FIV(-)- ve cats or FIV(-)+ ve cats of any health status. Regardless of health status, FIV(-)+ ve cats had a lower absolute count of small lymphocytes which were T cells (due to lower numbers of both CD4 + and CD8 + cells) than FIV(-)- ve cats. The numbers of small B cells were similar for both FIV(-)+ ve and FIV(-)- ve cats. However, there were no differences between FIV(-)+ ve and FIV(-)- ve cats in the absolute values of any subset of the large lymphocytes, which suggested that FIV may affect only small lymphocytes. Statistically, the inclusion or exclusion of the large lymphocyte population for routine lymphocyte subset analysis did not affect the overall results. However, because there were significant differences in subset distribution between small and large lymphocytes, analysis of both groups should be included in studies examining the role of lymphocytes in disease.

Analysis of leucocytes and lymphocyte subsets for different clinical stages of naturally acquired feline immunodeficiency virus infection.

We report alterations in leucocytes numbers and lymphocyte subset percentages, determined by flow cytometry, for three observed and previously defined clinical stages (asymptomatic carrier (AC), AIDS-related complex (ARC) and AIDS) of naturally occurring FIV infection. Unstaged FIV-positive cats had significantly lower numbers of total leucocytes (WCC) and neutrophils, lower percentages of PanT+ and CD4+, lower CD4:CD8 ratio and a higher percentage of B cells compared with unstaged FIV-negative cats. When FIV-positive cats were separated into clinical stages and compared with matched FIV-negative cats, AC FIV-positive cats had a significantly lower WCC, lower absolute numbers of neutrophils and lymphocytes, lower percentages of CD4+ and CD8+ cells, lower CD4:CD8 ratios and a higher percentage of B cells than healthy FIV-negative cats. ARC FIV-positive cats had lower percentages of PanT+ and CD4+ cells, lower CD4:CD8 ratios and higher percentages of B cells than matched FIV-negative cats. FIV-positive cats with AIDS had significantly lower percentages of CD4+ cells than matched FIV-negative cats. Comparisons among the three observed clinical stages of FIV-positive cats showed that AC FIV-positive cats had significantly lower WCC, significantly lower absolute numbers of neutrophils and a significantly lower percentage of CD8+ cells than ARC FIV-positive cats. AIDS FIV-positive cats had a significantly lower percentage of B cells than AC or ARC FIV-positive cats. FIV-positive cats had a similar leucocyte response to illness as FIV-negative cats but had consistently lower percentages of CD4+ lymphocytes. Thus, in the staging of FIV, a rise in the percentage of CD8+ lymphocytes could be used to distinguish between AC and ARC and a fall in the percentage of B lymphocytes could distinguish AIDS from AC and ARC.

Elevation of immunoglobulin deposition in the synovial membrane of dogs with cranial cruciate ligament rupture.

Synovial membrane biopsies were collected from 32 dogs with spontaneous cranial cruciate ligament rupture and seven control dogs. The subclasses of immunoglobulins in the synovial membrane of both the diseased and control dogs were examined with immunohistochemistry in combination with image analysis. IgG deposition was four-fold higher and IgM was eight-fold higher in dogs with spontaneous cranial crucial ligament (CrCL) rupture. These findings support the theory that there is an immune component to the inflammation associated with canine CrCL rupture. Further investigation is required to determine if these immune or inflammatory responses in CrCL rupture joints are the primary factor in ligament rupture or if they develop secondary to ligament rupture and instability.

Effect on topical 5-methoxypsoralen on tumorigenesis induced in albino and pigmented hairless mouse skin by UV irradiation.

A new line of the Skh:HRII hairless pigmented mouse (black juvenile coat) is described which has been selectively bred for the capacity to respond consistently to simulated solar UV radiation with a continuous and strong tan. This mouse demonstrates a degree of protection from chronic UV-induced tumorigenesis when compared with the Skh:HRI hairless albino mouse, and has been used here to study the effect of induced melanogenesis on phototumorigenesis. Mice were irradiated for 10 weeks with incremental doses of simulated solar UV radiation (UVA + B) from a fluorescent tube source which induced tumours in 100% of albino mice and 93% of black mice by 200 days (minimally oedemal), or with 60% of this dose (sub-oedemal) which induced tumours in 85% of albino mice and 65% of black mice. Mice were also exposed to the UVA component of these radiation sources, obtained by window glass filtration. The effect of topical 5-methoxypsoralen (5-MOP) was examined, at either 0.003% with minimally oedemal UVA + B or its UVA component alone, or at 0.01% with sub-oedemal UVA + B or its UVA component alone, in both albino and black mice. The 5-MOP concentrations were selected as the maximum concentration which did not increase the erythema and oedema responses after a single exposure to minimally oedemal or sub-oedemal UVA + B. At 200 days, the tumorigenic response to sub-oedemal UVA + B was significantly increased by topical 5-MOP, to 100% in albinos and 93% in black mice. In contrast, tumorigenesis in response to minimally oedemal UVA + B was unaffected by topical 5-MOP. The UVA component alone of either irradiation regime was not tumorigenic under these conditions. When combined with topical 5-MOP, the UVA of minimally oedemal UVA + B became moderately tumorigenic, and resulted in a tumour incidence of 23% in albinos and 14.5% in black mice. However, the UVA component of sub-oedemal UVA + B, when combined with topical 5-MOP, was highly tumorigenic specifically in albino mice, inducing tumours in 93% of albino mice but in only 27% of black mice. Tan intensity resulting from minimally oedemal UVA + B was not enhanced by topical 5-MOP, and its UVA component combined with 5-MOP resulted in only a minimal tan. However, the tan intensity resulting from sub-oedemal UVA + B with topical 5-MOP was strongly increased, although its UVA component combined with 5-MOP did not produce a perceptible tan.(ABSTRACT TRUNCATED AT 400 WORDS)

Chronic peritonitis and pancreatitis in a koala (Phascolarctos cinereus).

The gross, light microscopic and ultrastructural appearance of a nodular peritonitis accompanied by pancreatic changes in a Koala (Phascolarctos cinereus) is described. Its pathogenesis in relation to pancreatitis is discussed.

Tyzzer's disease (Bacillus piliformis) in Australian marsupials.

Tyzzer's disease (Bacillus piliformis infection) was diagnosed in nine marsupials (six possums, a koala, a wombat and a dasyurid). All but two of the possums were captive. Five of the seven marsupials, for which ages were recorded, were juvenile. Affected marsupials were either found dead or were showing non-specific illness for up to two days before death. Affected livers and hearts showed gross haemorrhage and scattered areas of white discolouration. Microscopically, areas of coagulative necrosis were often associated with neutrophilic infiltrates. Intracellular, slender, faintly basophilic rods were occasionally detected in HE-stained sections. Rods were shown by silver staining techniques to be associated with the lesions in all affected animals. These rods showed a beaded appearance when stained with methenamine silver and were consistently in packets within cells, on the peripheries of lesions and scattered sparsely and irregularly within the central necrotic regions.

Investigations of bone marrow dyscrasia in a poodle with macrocytosis.

A poodle-type dog with bone marrow dyscrasia and macrocytosis was investigated by clinicopathological, cytological and ultrastructural means. Peripheral blood analysis revealed macrocytosis and the presence of nucleated erythroid cells, some with nuclear/cytoplasmic asynchrony. Tendencies towards neutropenia and granulocytic hypersegmentation were observed. Bone marrow examination revealed low normal myeloid to erythroid ratio, the presence of megaloblasts and some giant metamyelocytes. In addition, there were abnormal mitoses, binuclearity and multinuclearity, incomplete nuclear membranes and nuclear clefts, intracytoplasmic parallel-sided membranes and apparent degenerate erythroid cells. Blood biochemical tests indicated normal to high concentrations of serum vitamin B12, serum folate and red cell folate. Transcobalamin I/IIIB12-binding capacity was similar to values for normal dogs, but transcobalamin II-binding capacity appeared high. It was concluded that the condition had similarities to both congenital dyserythropoietic disorders and true megaloblastic conditions, but until further investigations are reported it might be wise to refer to it as "bone marrow dyscrasia" in poodles.

A survey and review of hepatobiliary lesions in Australian macropods.

This report presents information on the range of diseases and lesions that occurred in sections of livers of macropods held in the Non-Domestic Animal Registry at Taronga Zoo. Of 142 affected livers, 52 were due to parasites, 24 to bacteria, nine to Macropod Herpesvirus, four to fungal agents and ten to tumours. In addition, 17 livers had acute degenerative or necrotic lesions, 22 were affected by fibrosis or other chronic lesions and four had miscellaneous degenerative lesions. Common parasitic diseases included toxoplasmosis, coccidial cholangitis, cestode cholangitis (Progamotaenia sp.), fascioliasis and capillarial hepatitis. Bacterial diseases were varied but lesions due to anaerobic bacteria or Mycobacteria spp. were most common. Many of the acute degenerative lesions were associated with cardio-respiratory disease. Chronic lesions were often of unknown origin, although it was speculated that parasitic and bacterial organisms contributed to the aetiology. There were four primary and six metastatic tumours.