Parasites and biological invasions: parallels, interactions, and control.

Species distributions are changing at an unprecedented rate owing to human activity. We examine how two key processes of redistribution - biological invasion and disease emergence - are interlinked. There are many parallels between invasion and emergence processes, and invasions can drive the spread of new diseases to wildlife. We examine the potential impacts of invasion and disease emergence, and discuss how these threats can be countered, focusing on biosecurity. In contrast with international policy on emerging diseases of humans and managed species, policy on invasive species and parasites of wildlife is fragmented, and the lack of international cooperation encourages individual parties to minimize their input into control. We call for international policy that acknowledges the strong links between emerging diseases and invasion risk.