Toxoplasmosis was introduced to Australia by cats, who also continue to spread the disease. It is known that the disease affects Australian mammals, and that many Australian mammals are suffering dramatic declines. It is completely unknown, however, whether toxoplasmosis is contributing to these declines and how it compares to other threats. This project will use field sampling, molecular work, lab experiments, and modelling to determine the impact of toxoplasmosis and its role in driving mammal declines across Australia.