MICHAEL BEGON, PHD, is Professor of Ecology in the Department of Evolution, Ecology and Behaviour at the University of Liverpool. He specialises in the ecology of infectious diseases in wildlife populations, focusing on diseases transmissible to humans.

COLIN R. TOWNSEND, is Professor Emeritus and Founding Director of the Ecology, Conservation and Biodiversity Research Group of Otago University. His research concerns the ecology of invasions and multiple stressors in stream ecosystems.