Jaw disease in kangaroos and wallabies, while uncommon in animals living in the free state, is a major cause of death in captive macropods. There are two major schools of thought regarding its aetiology. The first accepts the findings of Fox (1923) and considers the disease to be actinomycosis while the second believes jaw disease to be one manifestation of necrobacillosis. Regardless of the belief of the authors the clinical and pathological descriptions indicate the condition attacking macropods throughout the world is a single disease. / Over one hundred affected macropods were examined during the course of this study and few species were found to be spared from jaw disease. Cases of lumpy jaw most commonly occurred in the winter months. All ages of macropods were affected although a higher prevalence was recorded in younger animals; however this may have been a reflection of the age of macropods in the zoo under study. The most common site of infection was the premolar and anterior molar region of the oral cavity, regardless of the age of the animal. The gross pathological findings were similar to the descriptions of affected animals by various authors throughout the world. The site of infection could generally be recognized at the gingival crevice, commonly between teeth, and excessive calculus formation associated with gingivitis and gingival recession was a common finding in affected animals. Penetration of the gingival mucosae by plant fibre was not found to be a significant predisposing factor in the initiation of the disease. (For complete abstract open document.)

This thesis describes a comprehensive study of the cellular responses of a number of endangered marsupial species with a principal focus on the tammar wallaby (Macropus eugenii) as a model macropod species. The development of in vitro experimental assays for the assessment of immune responses in this model species are described, which provided a set of benchmarks for comparisons with other members of the Macropodidae and with eutherian mammals. Once this data was collected and protocols were established, the study was extended to include investigations of the immune responses in opportunistic samples obtained from the Rufous Hare-wallaby (Lagorchestes hirsutus), the Long-footed potoroo ( Potorous longipes) and the more common, but nonetheless still vulnerable, Long-nosed potoroo (Potorous tridactylus) with a view to investigating their apparent susceptibility to infection with intracellular pathogens, particularly mycobacterial species. The findings from the application of these assays suggest that the cellular immune responses of these species are relatively complex and involve a level of sophistication that rivals their eutherian counterparts. Specifically peripheral blood and tissue leukocytes were morphologically similar to those of other mammals, with the exception of tammar wallaby monocytes that appeared to contain few lysosomal granules, and the basophils of the Rufous Hare-wallaby that contained very large atypical granules. The overall findings of this study suggest that the immune systems of macropod species possess most of the sophistication associated with that of eutherian mammals. Whilst some differences were apparent in cells and their products in the test species, no single factor common to all macropods was identified as a cause for immune dysfunction. It appears likely that as yet undefined factors related to their confinement rather than an inherent defect in their immunocapacity is responsible for the apparent disease susceptibility of these animals. / Doctor of Philosophy (PhD)