The zoonotic potential of Tasmanian wildlife

Approximately eighty percent of all infectious diseases in hmnans are shared in nature by other animals. These diseases are termed as \zoonoses\". Most newly recognised human infections over the last fifty years have been zoonoses. As the continent of Australia is so isolated few diseases probably infected the Aborigines and most of the diseases that did infect them were in all likelihood zoonotic. Early explorers noted that Tasmanian Aborigines being even more isolated appeared to be relatively free from disease. With the arrival of the Europeans a whole new range of diseases affected the Aborigines including not only human diseases such as measles but also diseases of the domestic animals they brought with them. In Tasmania over the past two hundred years most of these imported diseases have either been eradicated or at least controlled. Examples are brucellosis and hydatid disease. With human activities moving into previously uninhabited areas we must therefore now look to the native animals as a potential source of human disease. A number of newly recognised zoonoses and potential zoonoses have emerged in recent times. Evidence is emerging of newly recognised parasitic diseases or diseases such as giardiasis previously thought to be specific to humans being actually zoonotic. This research project set out to examine what risk is posed by Tasmanian native animals in the spread disease to the human population. A survey of animals was carried out to determine what pathogenic bacteria and parasites were present. A number of Salmonella spp.( 4) were recorded along with 4 species of protozoa 2 species of nematode and 1 trematode. Due to reports of diarrhoea in bushwalkers a survey using an enzyme linked immunosorbent assay for Giardia species was carried out with surprising results antigens to Giardia sp. being detected in 5.5% of native animals.An indirect fluorescent antibody test was developed to survey the human population in an attempt to establish whether evidence existed to any widespread human infection with Trichinella pseudospiralis. The first human case of infection with this parasite thought to have originated in Tasmania having just been described. A number of positive samples were detected. The project has shown that although the risk is relatively low native animals do have the potential to serve as reservoirs for diseases of humans in Tasmania. This is especially so where humans eat meat from native animals or venture into more remote areas where water supplies may be contaminated."