Emerging zoonotic diseases have assumed increasing importance in public and animal health, as the last few years have seen a steady stream of new diseases, each emerging from an unsuspected quarter and causing severe problems for animals and humans. The reasons for disease emergence are multiple, but there are two main factors--expansion of the human population and globalisation of trade. Current issues such as the increasing movement of a variety of animal species, ecological disruption, uncultivatable organisms, and terrorism, all imply that emerging zoonotic diseases will in all probability, not only continue to occur, but will increase in the rate of their emergence. The recurring nature of the crises dictates that closer integration of veterinary and medical communities is warranted, along with improved education of the general public and policy makers.