Spontaneous proliferations in Australian marsupials--a survey and review. 2. Dasyurids and bandicoots.

This report catalogues all spontaneous proliferations in dasyurids and bandicoots held by the Comparative Pathology Registry at Taronga Zoo. Proliferative lesions were present in 70 dasyurids and three bandicoots. Hyperplastic or benign neoplastic masses in adrenals and livers were common in dasyurids. In addition, previously misdiagnosed splenic haematopoietic hyperplasia was common. A variety of mammary proliferations was present in dasyurids. Dasyurids often had multiple proliferative lesions. Lymphoid neoplasia was common, especially in the smaller dasyurids. No obvious aetiological factors have been identified in any of the tumour conditions in dasyurids although there is some evidence to suggest a genetic predisposition to lymphosarcoma in the fat-tailed antechinus.

Spontaneous proliferations in Australian marsupials--a survey and review. 1. Macropods, koalas, wombats, possums and gliders.

This report catalogues all spontaneous proliferations in macropods, koalas, wombats, and possums and gliders held by the Comparative Pathology Registry at Taronga Zoo. Proliferative lesions were present in 14 macropods, 26 koalas, two wombats and 22 possums and gliders. Most neoplasms recorded in macropods were singular and many were found incidentally. Lymphoid neoplasia, cranio-facial tumours and apparent mesotheliomas were common in koalas. Hyperplastic or benign neoplastic masses in adrenals and livers were common in possums. In addition, previously misdiagnosed splenic haematopoietic hyperplasia was common in these animals. Mammary proliferations were present in macropods and gliders. No obvious aetiological factors have been identified in any of the tumour conditions, although there is some evidence to suggest a viral involvement in lymphosarcoma in koalas.

Verminous bronchitis and bronchiolitis in potoroid marsupials associated with a new Capillaria sp.

We describe verminous bronchitis and bronchiolitis in potoroid marsupials associated with a new species of Capillaria resident in the epithelial lining of bronchi and bronchioles. The parasites was associated with alveolar oedema and emphysema, and a mixed inflammatory cell exudate within and surrounding the airways.

Systemic infection with a yeast-like organism in captive banded rock rattlesnakes (Crotalus lepidus klauberi).

Three captive banded rock rattlesnakes (Crotalus lepidus klauberi) died at Taronga Zoo, Sydney, Australia, between 1984 and 1987 with similar lesions in each case. Grossly, the liver and kidneys had multiple grey, fleshy nodules replacing much of the parenchyma. Histologically, these lesions were massive accumulations of yeast-like organisms, located mainly within macrophages in capillaries and sinusoids. There was little other inflammatory reaction. Organisms also were seen in the muscle and adventitial coats of the intestine, in the spleen, pancreas, brain, lungs, ovary, and fat body. Apparent budding was observed in fresh smears, and the organisms stained Gram-positive and periodic acid-Schiff positive but failed to grow on routine fungal media. Based on transmission electron microscopy, the organisms were typical yeast cells with thick, apparently single-layered cell walls showing evidence of enteroblastic proliferation. Two of the snakes had concurrent bacterial infections.

Mosaic 35,X/36,XY karyotype and intersex in a red panda (Ailurus fulgens fulgens).

A zoo-bred Himalayan red panda (Ailurus fulgens fulgens) was diagnosed as a presumptive intersex on clinical examination at 4-mo-of-age. The phenotype was predominantly female but showed a large anogenital distance and bilateral ischial swellings. Based on cytogenetic evaluation, the karyotype was mos35,X/36,XY, with 50% of each cell type. A grossly normal uterus and oviducts were seen with laparoscopic examination, while the gonads were smooth-surfaced, with a ramifying vascular pattern. On histopathologic examination the bulk of the gonads consisted of clumps of poorly differentiated cells, with just a thin rim of ovarian tissue under the region covered by the fimbriae of the oviduct.

Influence of environmental temperature on experimental infection of redfin perch (Perca fluviatilis) and rainbow trout (Oncorhynchus mykiss) with epizootic haematopoietic necrosis virus, an Australian iridovirus.

Experimental transmission of epizootic haematopoietic necrosis virus (EHNV) to adult redfin perch Perca fluviatilis and juvenile rainbow trout Oncorhynchus mykiss was undertaken at different water temperatures using intraperitoneal (IP) and bath inoculation. Redfin perch were highly susceptible to EHNV by both routes of infection. Bath inoculation with as few as 0.08 TCID50.mL-1 was lethal. The incubation period in redfin perch was about 11 days at a water temperature of 19-21 degrees C but was longer at colder temperatures and disease did not occur at temperatures below 12 degrees C. The longest incubation period recorded in redfin perch was 28 days. Rainbow trout were not susceptible to infection by bath inoculation but the disease was reproduced after IP inoculation with 10(5.6) TCID50 at water temperatures ranging from 8-21 degrees C. The incubation period was 3-10 days at 19-21 degrees C, but was up to 32 days at 8-10 degrees C. Persistent infection with EHNV was detected by virus isolation in a clinically unaffected rainbow trout after 63 days. The implications of these findings in the understanding of the epidemiology of EHNV infection are discussed.

Pathology of experimentally-induced, acute toxoplasmosis in macropods.

Thirteen Tammar wallabies (Macropus eugenii) were dosed orally with 500, 1000 or 10,000 oocysts of Toxoplasma gondii, as part of a vaccination trial. Eleven animals died of acute toxoplasmosis 9 to 15 days after challenge. The lesions were similar in all animals, consisting of foci of necrosis and inflammation in the intestines, lymphoid tissue, adrenal cortex, heart, skeletal muscle and brain, and severe generalised pulmonary congestion and oedema. Free and intracellular tachyzoites of Toxoplasma were associated with the lesions. The remaining 2 animals had shown no signs of disease when euthanased four months after challenge. Small, focal, non-suppurative inflammatory lesions were seen in brain, heart and skeletal muscle of these animals and chronic Toxoplasma infection was confirmed by mouse inoculation.