Emerging infectious diseases can have major impacts on wildlife including causing severe decline and extinction. For potentially emerging pathogens, sufficient data on prior absence (or a prior difference in disease dynamics) are frequently lacking for wildlife. Improved surveillance, particularly for neglected host taxa, geographical regions and infectious agents, would enable more effective management should emergence occur. Exposure to domestic sources of infection and human-assisted exposure to exotic wild sources were identified as the two main drivers of emergence across host taxa; the domestic source was primary for fish while the exotic wild source was primary for other taxa. There was generally insufficient evidence for major roles of other hypothesized drivers of emergence.