Aspects of the fatal malignant disease among the Tasmanian devil population (Sarcophilus laniarius)

The world's largest remaining marsupial carnivore, the Tasmanian devil (Sarcophilus laniarius, formerly harrisii) has over the last ten years been found to be suffering from a previously unknown and invariably fatal malignancy, now known as Devil Facial Tumour (DFT), which results in disfiguring and debilitating tumours of the facial skin and within the oral cavity. The disease has caused high mortality by apparently infectious spread and, with its high prevalence, seriously affects the continuing viability of the species. In the face of this epizootic, the devil has now been listed on Tasmania's and on Australia's threatened species registers as "vulnerable", below "endangered", "rare" and only one more step before "extinct". This paper describes the research challenges and outlines some approaches to the investigation of DFT pathobiology and aetiology. The environment of Tasmania is widely contaminated by human activities, whose residual health effects on native wildlife are unknown. The Tasmanien devil is the major carnivore at the head of a diverse native animal food chain of grazing herbivorous marsupials. The rôle of bioaccumulated persistent organic pollutants and possibly genotoxic chemicals requires investigation as do conventional infectious pathogens such as exogenous and endogenous viruses (or their genomes). Several potentially analogous conditions of known viral origin are described and recently the likelihood of infective cellular transmission from devil to devil has been reported. The risks inherent in any disease of unknown origin with potential to spread to other species cannot be overstressed.